@misc{BroekerBarbirz2017,
  author    = {Broeker, Nina K. and Barbirz, Stefanie},
  title     = {Not a barrier but a key: How bacteriophages exploit host's O\&\#8208;antigen as an essential receptor to initiate infection},
  series = {Molecular microbiology},
  volume    = {105},
  journal   = {Molecular microbiology},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {0950-382X},
  doi       = {10.1111/mmi.13729},
  pages     = {353 -- 357},
  year      = {2017},
  abstract  = {Tailed bacteriophages specific for Gram\&\#8208;negative bacteria encounter lipopolysaccharide (LPS) during the first infection steps. Yet, it is not well understood how biochemistry of these initial interactions relates to subsequent events that orchestrate phage adsorption and tail rearrangements to initiate cell entry. For many phages, long O\&\#8208;antigen chains found on the LPS of smooth bacterial strains serve as essential receptor recognized by their tailspike proteins (TSP). Many TSP are depolymerases and O\&\#8208;antigen cleavage was described as necessary step for subsequent orientation towards a secondary receptor. However, O\&\#8208;antigen specific host attachment must not always come along with O\&\#8208;antigen degradation. In this issue of Molecular Microbiology Prokhorov et al. report that coliphage G7C carries a TSP that deacetylates O\&\#8208;antigen but does not degrade it, whereas rough strains or strains lacking O\&\#8208;antigen acetylation remain unaffected. Bacteriophage G7C specifically functionalizes its tail by attaching the deacetylase TSP directly to a second TSP that is nonfunctional on the host's O\&\#8208;antigen. This challenges the view that bacteriophages use their TSP only to clear their way to a secondary receptor. Rather, O\&\#8208;antigen specific phages may employ enzymatically active TSP as a tool for irreversible LPS membrane binding to initiate subsequent infection steps.},
  language  = {en}
}
@article{DunsingIrmscherBarbirzetal.2019,
  author    = {Dunsing, Valentin and Irmscher, Tobias and Barbirz, Stefanie and Chiantia, Salvatore},
  title     = {Purely Polysaccharide-Based Biofilm Matrix Provides Size-Selective Diffusion Barriers for Nanoparticles and Bacteriophages},
  series = {Biomacromolecules : an interdisciplinary journal focused at the interface of polymer science and the biological sciences},
  volume    = {20},
  journal   = {Biomacromolecules : an interdisciplinary journal focused at the interface of polymer science and the biological sciences},
  number    = {10},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1525-7797},
  doi       = {10.1021/acs.biomac.9b00938},
  pages     = {3842 -- 3854},
  year      = {2019},
  abstract  = {Biofilms are complex mixtures of proteins, DNA, and polysaccharides surrounding bacterial communities as protective barriers that can be biochemically modified during the bacterial life cycle. However, their compositional heterogeneity impedes a precise analysis of the contributions of individual matrix components to the biofilm structural organization. To investigate the structural properties of glycan-based biofilms, we analyzed the diffusion dynamics of nanometer-sized objects in matrices of the megadalton-sized anionic polysaccharide, stewartan, the major biofilm component of the plant pathogen, Pantoea stewartii. Fluorescence correlation spectroscopy and single-particle tracking of nanobeads and bacteriophages indicated notable subdiffusive dynamics dependent on probe size and stewartan concentration, in contrast to free diffusion of small molecules. Stewartan enzymatic depolymerization by bacteriophage tailspike proteins rapidly restored unhindered diffusion. We, thus, hypothesize that the glycan polymer stewartan determines the major physicochemical properties of the biofilm, which acts as a selective diffusion barrier for nanometer-sized objects and can be controlled by enzymes.},
  language  = {en}
}
@article{SchmidtRabschBroekeretal.2016,
  author    = {Schmidt, Andreas and Rabsch, Wolfgang and Broeker, Nina K. and Barbirz, Stefanie},
  title     = {Bacteriophage tailspike protein based assay to monitor phase variable glucosylations in Salmonella O-antigens},
  series = {BMC microbiology},
  volume    = {16},
  journal   = {BMC microbiology},
  publisher = {BioMed Central},
  address   = {London},
  issn      = {1471-2180},
  doi       = {10.1186/s12866-016-0826-0},
  pages     = {11},
  year      = {2016},
  abstract  = {Background Non-typhoid Salmonella Typhimurium (S. Typhimurium) accounts for a high number of registered salmonellosis cases, and O-serotyping is one important tool for monitoring epidemiology and spread of the disease. Moreover, variations in glucosylated O-antigens are related to immunogenicity and spread in the host. However, classical autoagglutination tests combined with the analysis of specific genetic markers cannot always reliably register phase variable glucose modifications expressed on Salmonella O-antigens and additional tools to monitor O-antigen glucosylation phenotypes of S. Typhimurium would be desirable. Results We developed a test for the phase variable O-antigen glucosylation state of S. Typhimurium using the tailspike proteins (TSP) of Salmonella phages 9NA and P22. We used this ELISA like tailspike adsorption (ELITA) assay to analyze a library of 44 Salmonella strains. ELITA was successful in discriminating strains that carried glucose 1-6 linked to the galactose of O-polysaccharide backbone (serotype O1) from non-glucosylated strains. This was shown by O-antigen compositional analyses of the respective strains with mass spectrometry and capillary electrophoresis. The ELITA test worked rapidly in a microtiter plate format and was highly O-antigen specific. Moreover, TSP as probes could also detect glucosylated strains in flow cytometry and distinguish multiphasic cultures differing in their glucosylation state. Conclusions Tailspike proteins contain large binding sites with precisely defined specificities and are therefore promising tools to be included in serotyping procedures as rapid serotyping agents in addition to antibodies. In this study, 9NA and P22TSP as probes could specifically distinguish glucosylation phenotypes of Salmonella on microtiter plate assays and in flow cytometry. This opens the possibility for flow sorting of cell populations for subsequent genetic analyses or for monitoring phase variations during large scale O-antigen preparations necessary for vaccine production.},
  language  = {en}
}
@misc{SchmidtRabschBroekeretal.2017,
  author    = {Schmidt, Andreas and Rabsch, Wolfgang and Broeker, Nina K. and Barbirz, Stefanie},
  title     = {Bacteriophage tailspike protein based assay to monitor phase variable glucosylations in Salmonella O-antigens},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-103769},
  pages     = {11},
  year      = {2017},
  abstract  = {Background Non-typhoid Salmonella Typhimurium (S. Typhimurium) accounts for a high number of registered salmonellosis cases, and O-serotyping is one important tool for monitoring epidemiology and spread of the disease. Moreover, variations in glucosylated O-antigens are related to immunogenicity and spread in the host. However, classical autoagglutination tests combined with the analysis of specific genetic markers cannot always reliably register phase variable glucose modifications expressed on Salmonella O-antigens and additional tools to monitor O-antigen glucosylation phenotypes of S. Typhimurium would be desirable. Results We developed a test for the phase variable O-antigen glucosylation state of S. Typhimurium using the tailspike proteins (TSP) of Salmonella phages 9NA and P22. We used this ELISA like tailspike adsorption (ELITA) assay to analyze a library of 44 Salmonella strains. ELITA was successful in discriminating strains that carried glucose 1-6 linked to the galactose of O-polysaccharide backbone (serotype O1) from non-glucosylated strains. This was shown by O-antigen compositional analyses of the respective strains with mass spectrometry and capillary electrophoresis. The ELITA test worked rapidly in a microtiter plate format and was highly O-antigen specific. Moreover, TSP as probes could also detect glucosylated strains in flow cytometry and distinguish multiphasic cultures differing in their glucosylation state. Conclusions Tailspike proteins contain large binding sites with precisely defined specificities and are therefore promising tools to be included in serotyping procedures as rapid serotyping agents in addition to antibodies. In this study, 9NA and P22TSP as probes could specifically distinguish glucosylation phenotypes of Salmonella on microtiter plate assays and in flow cytometry. This opens the possibility for flow sorting of cell populations for subsequent genetic analyses or for monitoring phase variations during large scale O-antigen preparations necessary for vaccine production.},
  language  = {en}
}
@phdthesis{Barbirz2005,
  author    = {Barbirz, Stefanie},
  title     = {Konservierte Struktur bei genetischer Mosaizit{\"a}t : die Tailspike Proteine dreier Phagen der Familie Podviridae},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-6885},
  school      = {Universit{\"a}t Potsdam},
  year      = {2005},
  abstract  = {Die Tailspike Proteine (TSP) der Bakteriophagen P22, Sf6 und HK620 dienen der Erkennung von Kohlenhydratstrukturen auf ihren gram-negativen Wirtsbakterien und zeigen, von den ersten 110 Aminos{\"a}uren des N-Terminus abgesehen, keine Sequenz{\"u}bereinstimmung. Mit R{\"o}ntgenkristallstrukturanalyse konnte gezeigt werden, dass HK620TSP und Sf6TSP ebenfalls zu einer parallelen, rechtsg{\"a}ngigen beta-Helix falten, wie dies schon f{\"u}r P22TSP bekannt war. Die Kohlenhydratbindestelle ist bei Sf6TSP im Vergleich zu P22TSP zwischen die Untereinheiten verschoben.},
  subject      = {Bakteriophagen},
  language  = {de}
}
@article{GeorgievGrafmuellerBlegeretal.2018,
  author    = {Georgiev, Vasil N. and Grafm{\"u}ller, Andrea and Bl{\´e}ger, David and Hecht, Stefan and Kunstmann, Sonja and Barbirz, Stefanie and Lipowsky, Reinhard and Dimova, Rumiana},
  title     = {Area increase and budding in giant vesicles triggered by light},
  series = {Advanced science},
  volume    = {5},
  journal   = {Advanced science},
  number    = {8},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {2198-3844},
  doi       = {10.1002/advs.201800432},
  pages     = {9},
  year      = {2018},
  abstract  = {Biomembranes are constantly remodeled and in cells, these processes are controlled and modulated by an assortment of membrane proteins. Here, it is shown that such remodeling can also be induced by photoresponsive molecules. The morphological control of giant vesicles in the presence of a water-soluble ortho-tetrafluoroazobenzene photoswitch (F-azo) is demonstrated and it is shown that the shape transformations are based on an increase in membrane area and generation of spontaneous curvature. The vesicles exhibit budding and the buds can be retracted by using light of a different wavelength. In the presence of F-azo, the membrane area can increase by more than 5\% as assessed from vesicle electrodeformation. To elucidate the underlying molecular mechanism and the partitioning of F-azo in the membrane, molecular dynamics simulations are employed. Comparison with theoretically calculated shapes reveals that the budded shapes are governed by curvature elasticity, that the spontaneous curvature can be decomposed into a local and a nonlocal contribution, and that the local spontaneous curvature is about 1/(2.5 mu m). The results show that exo- and endocytotic events can be controlled by light and that these photoinduced processes provide an attractive method to change membrane area and morphology.},
  language  = {en}
}
@article{KunstmannGohlkeBroekeretal.2018,
  author    = {Kunstmann, Ruth Sonja and Gohlke, Ulrich and Br{\"o}ker, Nina Kristin and Roske, Yvette and Heinemann, Udo and Santer, Mark and Barbirz, Stefanie},
  title     = {Solvent networks tune thermodynamics of oligosaccharide complex formation in an extended protein binding site},
  series = {Journal of the American Chemical Society},
  volume    = {140},
  journal   = {Journal of the American Chemical Society},
  number    = {33},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {0002-7863},
  doi       = {10.1021/jacs.8b03719},
  pages     = {10447 -- 10455},
  year      = {2018},
  abstract  = {The principles of protein-glycan binding are still not well understood on a molecular level. Attempts to link affinity and specificity of glycan recognition to structure suffer from the general lack of model systems for experimental studies and the difficulty to describe the influence of solvent. We have experimentally and computationally addressed energetic contributions of solvent in protein-glycan complex formation in the tailspike protein (TSP) of E. coli bacteriophage HK620. HK620TSP is a 230 kDa native trimer of right-handed, parallel beta-helices that provide extended, rigid binding sites for bacterial cell surface O-antigen polysaccharides. A set of high affinity mutants bound hexa- or pentasaccharide O-antigen fragments with very similar affinities even though hexasaccharides introduce an additional glucose branch into an occluded protein surface cavity. Remarkably different thermodynamic binding signatures were found for different mutants; however, crystal structure analyses indicated that no major oligosaccharide or protein topology changes had occurred upon complex formation. This pointed to a solvent effect. Molecular dynamics simulations using a mobility-based approach revealed an extended network of solvent positions distributed over the entire oligosaccharide binding site. However, free energy calculations showed that a small water network inside the glucose-binding cavity had the most notable influence on the thermodynamic signature. The energy needed to displace water from the glucose binding pocket depended on the amino acid at the entrance, in agreement with the different amounts of enthalpy-entropy compensation found for introducing glucose into the pocket in the different mutants. Studies with small molecule drugs have shown before that a few active water molecules can control protein complex formation. HK620TSP oligosaccharide binding shows that similar fundamental principles also apply for glycans, where a small number of water molecules can dominate the thermodynamic signature in an extended binding site.},
  language  = {en}
}
@misc{DunsingIrmscherBarbirzetal.2019,
  author    = {Dunsing, Valentin and Irmscher, Tobias and Barbirz, Stefanie and Chiantia, Salvatore},
  title     = {Microviscosity of bacterial biofilm matrix characterized by fluorescence correlation spectroscopy and single particle tracking},
  series = {European biophysics journal : with biophysics letters ; an international journal of biophysics},
  volume    = {48},
  journal   = {European biophysics journal : with biophysics letters ; an international journal of biophysics},
  publisher = {Springer},
  address   = {New York},
  issn      = {0175-7571},
  doi       = {https://doi.org/10.1007/s00249-019-01373-4},
  pages     = {S115 -- S115},
  year      = {2019},
  language  = {en}
}
@article{BarbirzBeckerFreibergetal.2009,
  author    = {Barbirz, Stefanie and Becker, Marion and Freiberg, Alexander and Seckler, Robert},
  title     = {Phage tailspike proteins with beta-solenoid fold as thermostable carbohydrate binding materials},
  issn      = {1616-5187},
  doi       = {10.1002/mabi.200800278},
  year      = {2009},
  abstract  = {We have investigated the stability of three tailspike proteins (TSPs) from bacteriophages Sf6, P22, and HK620. Tailspikes are rod-like homotrimers with comparable beta-solenoid folds and similarly high kinetic stability in spite of different amino acid sequences. As tailspikes bind polysaccharides to recognize the bacterial host cell, their stability is required for maintenance of bacteriophage infectivity under harsh extracellular conditions. They resist denaturation by SDS at ambient temperature and their unfolding is slow even in 6 m guanidinium hydrochloride (GdmHCl). This makes them interesting candidates for very stable carbohydrate binding protein materials.},
  language  = {en}
}
@article{BarbirzMuellerUetrechtetal.2008,
  author    = {Barbirz, Stefanie and M{\"u}ller, J{\"u}rgen J. and Uetrecht, Charlotte and Clark, Alvin J. and Heinemann, Udo and Seckler, Robert},
  title     = {Crystal structure of Escherichia coli phage HK620 tailspike : podoviral tailspike endoglycosidase modules are evolutionarily related},
  issn      = {0950-382X},
  year      = {2008},
  abstract  = {Bacteriophage HK620 infects Escherichia coli H and is closely related to Shigella phage Sf6 and Salmonella phage P22. All three Podoviridae recognize and cleave their respective host cell receptor polysaccharide by homotrimeric tailspike proteins. The three proteins exhibit high sequence identity in the 110 residues of their N-terminal particle- binding domains, but no apparent sequence similarity in their major, receptor-binding parts. We have biochemically characterized the receptor-binding part of HK620 tailspike and determined its crystal structure to 1.38 {\AA} resolution. Its major domain is a right-handed parallel ;-helix, as in Sf6 and P22 tailspikes. HK620 tailspike has endo-N- acetylglucosaminidase activity and produces hexasaccharides of an O18A1-type O-antigen. As indicated by the structure of a hexasaccharide complex determined at 1.6 {\AA} resolution, the endoglycosidase-active sites are located intramolecularly, as in P22, and not between subunits, as in Sf6 tailspike. In contrast, the extreme C-terminal domain of HK620 tailspike forms a ;-sandwich, as in Sf6 and unlike P22 tailspike. Despite the different folds, structure-based sequence alignments of the C-termini reveal motifs conserved between the three proteins. We propose that the tailspike genes of P22, Sf6 and HK620 have a common precursor and are not mosaics of unrelated gene fragments.},
  language  = {en}
}
@article{MuellerBarbirzHeinleetal.2008,
  author    = {M{\"u}ller, J{\"u}rgen J. and Barbirz, Stefanie and Heinle, Karolin and Freiberg, Alexander and Seckler, Robert and Heinemann, Udo},
  title     = {An intersubunit active site between supercoiled parallel beta helices in the trimeric tailspike endorhamnosidase of Shigella flexneri phage Sf6},
  doi       = {10.1016/j.str.2008.01.019},
  year      = {2008},
  abstract  = {Sf6 belongs to the Podoviridae family of temperate bacteriophages that infect gram-negative bacteria by insertion of their double-stranded DNA. They attach to their hosts specifically via their tailspike proteins. The 1.25 {\AA} crystal structure of Shigella phage Sf6 tailspike protein (Sf6 TSP) reveals a conserved architecture with a central, right-handed ; helix. In the trimer of Sf6 TSP, the parallel ; helices form a left-handed, coiled;; coil with a pitch of 340 {\AA}. The C-terminal domain consists of a ; sandwich reminiscent of viral capsid proteins. Further crystallographic and biochemical analyses show a Shigella cell wall O-antigen fragment to bind to an endorhamnosidase active site located between two ;-helix subunits each anchoring one catalytic carboxylate. The functionally and structurally related bacteriophage, P22 TSP, lacks sequence identity with Sf6 TSP and has its active sites on single subunits. Sf6 TSP may serve as an example for the evolution of different host specificities on a similar general architecture.},
  language  = {en}
}
@article{AndresGohlkeBroekeretal.2013,
  author    = {Andres, Dorothee and Gohlke, Ulrich and Br{\"o}ker, Nina Kristin and Schulze, Stefan and Rabsch, Wolfgang and Heinemann, Udo and Barbirz, Stefanie and Seckler, Robert},
  title     = {An essential serotype recognition pocket on phage P22 tailspike protein forces Salmonella enterica serovar Paratyphi A O-antigen fragments to bind as nonsolution conformers},
  series = {Glycobiology},
  volume    = {23},
  journal   = {Glycobiology},
  number    = {4},
  publisher = {Oxford Univ. Press},
  address   = {Cary},
  issn      = {0959-6658},
  doi       = {10.1093/glycob/cws224},
  pages     = {486 -- 494},
  year      = {2013},
  abstract  = {Bacteriophage P22 recognizes O-antigen polysaccharides of Salmonella enterica subsp. enterica (S.) with its tailspike protein (TSP). In the serovars S. Typhimurium, S. Enteritidis, and S. Paratyphi A, the tetrasaccharide repeat units of the respective O-antigens consist of an identical main chain trisaccharide but different 3,6-dideoxyhexose substituents. Here, the epimers abequose, tyvelose and paratose determine the specific serotype. P22 TSP recognizes O-antigen octasaccharides in an extended binding site with a single 3,6-dideoxyhexose binding pocket. We have isolated S. Paratyphi A octasaccharides which were not available previously and determined the crystal structure of their complex with P22 TSP. We discuss our data together with crystal structures of complexes with S. Typhimurium and S. Enteritidis octasaccharides determined earlier. Isothermal titration calorimetry showed that S. Paratyphi A octasaccharide binds P22 TSP less tightly, with a difference in binding free energy of similar to 7 kJ mol(-1) at 20 degrees C compared with S. Typhimurium and S. Enteritidis octasaccharides. Individual protein-carbohydrate contacts were probed by amino acid replacements showing that the dideoxyhexose pocket contributes to binding of all three serotypes. However, S. Paratyphi A octasaccharides bind in a conformation with an energetically unfavorable phi/epsilon glycosidic bond angle combination. In contrast, octasaccharides from the other serotypes bind as solution-like conformers. Two water molecules are conserved in all P22 TSP complexes with octasaccharides of different serotypes. They line the dideoxyhexose binding pocket and force the S. Paratyphi A octasaccharides to bind as nonsolution conformers. This emphasizes the role of solvent as part of carbohydrate binding sites.},
  language  = {en}
}
@inproceedings{SmithMattosBarbirz2013,
  author    = {Smith, Mychal Daijon and Mattos, Carla and Barbirz, Stefanie},
  title     = {The multiple solvent crystal structures method of P22TSP},
  series = {The FASEB journal : the official journal of the Federation of American Societies for Experimental Biology},
  volume    = {27},
  booktitle = {The FASEB journal : the official journal of the Federation of American Societies for Experimental Biology},
  number    = {11},
  publisher = {Federation of American Societies for Experimental Biology},
  address   = {Bethesda},
  issn      = {0892-6638},
  pages     = {1},
  year      = {2013},
  language  = {en}
}
@article{AndresRoskeDoeringetal.2012,
  author    = {Andres, Dorothee and Roske, Yvette and Doering, Carolin and Heinemann, Udo and Seckler, Robert and Barbirz, Stefanie},
  title     = {Tail morphology controls DNA release in two Salmonella phages with one lipopolysaccharide receptor recognition system},
  series = {Molecular microbiology},
  volume    = {83},
  journal   = {Molecular microbiology},
  number    = {6},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {0950-382X},
  doi       = {10.1111/j.1365-2958.2012.08006.x},
  pages     = {1244 -- 1253},
  year      = {2012},
  abstract  = {Bacteriophages use specific tail proteins to recognize host cells. It is still not understood to molecular detail how the signal is transmitted over the tail to initiate infection. We have analysed in vitro DNA ejection in long-tailed siphovirus 9NA and short-tailed podovirus P22 upon incubation with Salmonella typhimurium lipopolysaccharide (LPS). We showed for the first time that LPS alone was sufficient to elicit DNA release from a siphovirus in vitro. Crystal structure analysis revealed that both phages use similar tailspike proteins for LPS recognition. Tailspike proteins hydrolyse LPS O antigen to position the phage on the cell surface. Thus we were able to compare in vitro DNA ejection processes from two phages with different morphologies with the same receptor under identical experimental conditions. Siphovirus 9NA ejected its DNA about 30 times faster than podovirus P22. DNA ejection is under control of the conformational opening of the particle and has a similar activation barrier in 9NA and P22. Our data suggest that tail morphology influences the efficiencies of particle opening given an identical initial receptor interaction event.},
  language  = {en}
}
@inproceedings{DonohueSmithBroekeretal.2015,
  author    = {Donohue, Patrick and Smith, Mychal Daijon and Br{\"o}ker, Nina Kristin and Doering, Carolin and Mattos, Carla and Barbirz, Stefanie},
  title     = {Multiple Solvent Crystal Structures of phage P22 tailspike protein: An analysis of binding site hot spots and surface hydration},
  series = {The FASEB journal : the official journal of the Federation of American Societies for Experimental Biology},
  volume    = {29},
  booktitle = {The FASEB journal : the official journal of the Federation of American Societies for Experimental Biology},
  publisher = {Federation of American Societies for Experimental Biology},
  address   = {Bethesda},
  issn      = {0892-6638},
  pages     = {1},
  year      = {2015},
  language  = {en}
}
@article{ZaccheusBroekerLundborgetal.2012,
  author    = {Zaccheus, Mona V. and Br{\"o}ker, Nina Kristin and Lundborg, Magnus and Uetrecht, Charlotte and Barbirz, Stefanie and Widmalm, Goran},
  title     = {Structural studies of the O-antigen polysaccharide from Escherichia coli TD2158 having O18 serogroup specificity and aspects of its interaction with the tailspike endoglycosidase of the infecting bacteriophage HK620},
  series = {Carbohydrate research},
  volume    = {357},
  journal   = {Carbohydrate research},
  number    = {8},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0008-6215},
  doi       = {10.1016/j.carres.2012.05.022},
  pages     = {118 -- 125},
  year      = {2012},
  abstract  = {We have analyzed the O-antigen polysaccharide of the previously uncharacterized Escherichia coli strain TD2158 which is a host of bacteriophage HK620. This bacteriophage recognizes and cleaves the polysaccharide with its tailspike protein (TSP). The polysaccharide preparation as well as oligosaccharides obtained from HK620TSP endoglycosidase digests were analyzed with NMR spectroscopy. Additionally, sugar analysis was performed on the O-antigen polysaccharide and MALDI-TOF MS was used in oligosaccharide analysis. The present study revealed a heterogeneous polysaccharide with a hexasaccharide repeating unit of the following structure: alpha-D-Glcp-(1 -> 6) vertical bar vertical bar 2)-alpha-L-Rhap-(1 -> 6)-alpha-D-Glcp-(1 -> 4)-alpha-D-Galp-(1 -> 3)-alpha-D-GlcpNAc- (1 ->vertical bar beta-D-Glcp/beta-D-GlcpNAc-(1 -> 3) A repeating unit with a D-GlcNAc substitution of D-Gal has been described earlier as characteristic for serogroup O18A1. Accordingly, we termed repeating units with D-Glc substitution at D-Gal as O18A2. NMR analyses of the polysaccharide confirmed that O18A1- and O18A2-type repeats were present in a 1:1 ratio. However, HK620TSP preferentially bound the D-GlcNAc- substituted O18A1-type repeating units in its high affinity binding pocket with a dissociation constant of 140 mu M and disfavored the O18A2-type having a beta-D-Glcp-(1 -> 3)-linked group. As a result, in hexasaccharide preparations, O18A1 and O18A2 repeats were present in a 9: 1 ratio stressing the clear preference of O18A1- type repeats to be cleaved by HK620TSP.},
  language  = {en}
}
@article{BroekerGohlkeMuelleretal.2013,
  author    = {Br{\"o}ker, Nina Kristin and Gohlke, Ulrich and M{\"u}ller, J{\"u}rgen J. and Uetrecht, Charlotte and Heinemann, Udo and Seckler, Robert and Barbirz, Stefanie},
  title     = {Single amino acid exchange in bacteriophage HK620 tailspike protein results in thousand-fold increase of its oligosaccharide affinity},
  series = {Glycobiology},
  volume    = {23},
  journal   = {Glycobiology},
  number    = {1},
  publisher = {Oxford Univ. Press},
  address   = {Cary},
  issn      = {0959-6658},
  doi       = {10.1093/glycob/cws126},
  pages     = {59 -- 68},
  year      = {2013},
  abstract  = {Bacteriophage HK620 recognizes and cleaves the O-antigen polysaccharide of Escherichia coli serogroup O18A1 with its tailspike protein (TSP). HK620TSP binds hexasaccharide fragments with low affinity, but single amino acid exchanges generated a set of high-affinity mutants with submicromolar dissociation constants. Isothermal titration calorimetry showed that only small amounts of heat were released upon complex formation via a large number of direct and solvent-mediated hydrogen bonds between carbohydrate and protein. At room temperature, association was both enthalpy- and entropy-driven emphasizing major solvent rearrangements upon complex formation. Crystal structure analysis showed identical protein and sugar conformers in the TSP complexes regardless of their hexasaccharide affinity. Only in one case, a TSP mutant bound a different hexasaccharide conformer. The extended sugar binding site could be dissected in two regions: first, a hydrophobic pocket at the reducing end with minor affinity contributions. Access to this site could be blocked by a single aspartate to asparagine exchange without major loss in hexasaccharide affinity. Second, a region where the specific exchange of glutamate for glutamine created a site for an additional water molecule. Side-chain rearrangements upon sugar binding led to desolvation and additional hydrogen bonding which define this region of the binding site as the high-affinity scaffold.},
  language  = {en}
}
@phdthesis{Barbirz2017,
  author    = {Barbirz, Stefanie},
  title     = {Highly specific binders for bacterial polysaccharides},
  school      = {Universit{\"a}t Potsdam},
  pages     = {167},
  year      = {2017},
  language  = {en}
}
@article{SchmidtRabschBroekeretal.2016,
  author    = {Schmidt, Andreas and Rabsch, Wolfgang and Br{\"o}ker, Nina Kristin and Barbirz, Stefanie},
  title     = {Bacteriophage tailspike protein based assay to monitor phase variable glucosylations in Salmonella O-antigens},
  series = {BMC microbiology},
  volume    = {16},
  journal   = {BMC microbiology},
  publisher = {BioMed Central},
  address   = {London},
  issn      = {1471-2180},
  doi       = {10.1186/s12866-016-0826-0},
  pages     = {2214 -- 2226},
  year      = {2016},
  abstract  = {Background: Non-typhoid Salmonella Typhimurium (S. Typhimurium) accounts for a high number of registered salmonellosis cases, and O-serotyping is one important tool for monitoring epidemiology and spread of the disease. Moreover, variations in glucosylated O-antigens are related to immunogenicity and spread in the host. However, classical autoagglutination tests combined with the analysis of specific genetic markers cannot always reliably register phase variable glucose modifications expressed on Salmonella O-antigens and additional tools to monitor O-antigen glucosylation phenotypes of S. Typhimurium would be desirable. Results: We developed a test for the phase variable O-antigen glucosylation state of S. Typhimurium using the tailspike proteins (TSP) of Salmonella phages 9NA and P22. We used this ELISA like tailspike adsorption (ELITA) assay to analyze a library of 44 Salmonella strains. ELITA was successful in discriminating strains that carried glucose 1-6 linked to the galactose of O-polysaccharide backbone (serotype O1) from non-glucosylated strains. This was shown by O-antigen compositional analyses of the respective strains with mass spectrometry and capillary electrophoresis. The ELITA test worked rapidly in a microtiter plate format and was highly O-antigen specific. Moreover, TSP as probes could also detect glucosylated strains in flow cytometry and distinguish multiphasic cultures differing in their glucosylation state. Conclusions: Tailspike proteins contain large binding sites with precisely defined specificities and are therefore promising tools to be included in serotyping procedures as rapid serotyping agents in addition to antibodies. In this study, 9NA and P22TSP as probes could specifically distinguish glucosylation phenotypes of Salmonella on microtiter plate assays and in flow cytometry. This opens the possibility for flow sorting of cell populations for subsequent genetic analyses or for monitoring phase variations during large scale O-antigen preparations necessary for vaccine production.},
  language  = {en}
}
@misc{KunstmannScheidtBuchwaldetal.2018,
  author    = {Kunstmann, Ruth Sonja and Scheidt, Tom and Buchwald, Saskia and Helm, Alexandra and Mulard, Laurence A. and Fruth, Angelika and Barbirz, Stefanie},
  title     = {Bacteriophage Sf6 Tailspike Protein for Detection of Shigella flexneri Pathogens},
  series = {Viruses},
  journal   = {Viruses},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-417831},
  pages     = {18},
  year      = {2018},
  abstract  = {Bacteriophage research is gaining more importance due to increasing antibiotic resistance. However, for treatment with bacteriophages, diagnostics have to be improved. Bacteriophages carry adhesion proteins, which bind to the bacterial cell surface, for example tailspike proteins (TSP) for specific recognition of bacterial O-antigen polysaccharide. TSP are highly stable proteins and thus might be suitable components for the integration into diagnostic tools. We used the TSP of bacteriophage Sf6 to establish two applications for detecting Shigella flexneri (S. flexneri), a highly contagious pathogen causing dysentery. We found that Sf6TSP not only bound O-antigen of S. flexneri serotype Y, but also the glucosylated O-antigen of serotype 2a. Moreover, mass spectrometry glycan analyses showed that Sf6TSP tolerated various O-acetyl modifications on these O-antigens. We established a microtiter plate-based ELISA like tailspike adsorption assay (ELITA) using a Strep-tag®II modified Sf6TSP. As sensitive screening alternative we produced a fluorescently labeled Sf6TSP via coupling to an environment sensitive dye. Binding of this probe to the S. flexneri O-antigen Y elicited a fluorescence intensity increase of 80\% with an emission maximum in the visible light range. The Sf6TSP probes thus offer a promising route to a highly specific and sensitive bacteriophage TSP-based Shigella detection system.},
  language  = {en}
}
@article{KunstmannScheidtBuchwaldetal.2018,
  author    = {Kunstmann, Ruth Sonja and Scheidt, Tom and Buchwald, Saskia and Helm, Alexandra and Mulard, Laurence A. and Fruth, Angelika and Barbirz, Stefanie},
  title     = {Bacteriophage Sf6 Tailspike Protein for Detection of Shigella flexneri Pathogens},
  series = {Viruses},
  volume    = {10},
  journal   = {Viruses},
  number    = {8},
  publisher = {Molecular Diversity Preservation International (MDPI)},
  address   = {Basel},
  issn      = {1999-4915},
  doi       = {10.3390/v10080431},
  pages     = {1 -- 18},
  year      = {2018},
  abstract  = {Bacteriophage research is gaining more importance due to increasing antibiotic resistance. However, for treatment with bacteriophages, diagnostics have to be improved. Bacteriophages carry adhesion proteins, which bind to the bacterial cell surface, for example tailspike proteins (TSP) for specific recognition of bacterial O-antigen polysaccharide. TSP are highly stable proteins and thus might be suitable components for the integration into diagnostic tools. We used the TSP of bacteriophage Sf6 to establish two applications for detecting Shigella flexneri (S. flexneri), a highly contagious pathogen causing dysentery. We found that Sf6TSP not only bound O-antigen of S. flexneri serotype Y, but also the glucosylated O-antigen of serotype 2a. Moreover, mass spectrometry glycan analyses showed that Sf6TSP tolerated various O-acetyl modifications on these O-antigens. We established a microtiter plate-based ELISA like tailspike adsorption assay (ELITA) using a Strep-tag®II modified Sf6TSP. As sensitive screening alternative we produced a fluorescently labeled Sf6TSP via coupling to an environment sensitive dye. Binding of this probe to the S. flexneri O-antigen Y elicited a fluorescence intensity increase of 80\% with an emission maximum in the visible light range. The Sf6TSP probes thus offer a promising route to a highly specific and sensitive bacteriophage TSP-based Shigella detection system.},
  language  = {en}
}
@misc{GeorgievGrafmuellerBlegeretal.2018,
  author    = {Georgiev, Vasil N. and Grafm{\"u}ller, Andrea and Bl{\´e}ger, David and Hecht, Stefan and Kunstmann, Ruth Sonja and Barbirz, Stefanie and Lipowsky, Reinhard and Dimova, Rumiana},
  title     = {Area increase and budding in giant vesicles triggered by light},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  volume    = {5},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {733},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-42629},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-426298},
  pages     = {9},
  year      = {2018},
  abstract  = {Biomembranes are constantly remodeled and in cells, these processes are controlled and modulated by an assortment of membrane proteins. Here, it is shown that such remodeling can also be induced by photoresponsive molecules. The morphological control of giant vesicles in the presence of a water-soluble ortho-tetrafluoroazobenzene photoswitch (F-azo) is demonstrated and it is shown that the shape transformations are based on an increase in membrane area and generation of spontaneous curvature. The vesicles exhibit budding and the buds can be retracted by using light of a different wavelength. In the presence of F-azo, the membrane area can increase by more than 5\% as assessed from vesicle electrodeformation. To elucidate the underlying molecular mechanism and the partitioning of F-azo in the membrane, molecular dynamics simulations are employed. Comparison with theoretically calculated shapes reveals that the budded shapes are governed by curvature elasticity, that the spontaneous curvature can be decomposed into a local and a nonlocal contribution, and that the local spontaneous curvature is about 1/(2.5 mu m). The results show that exo- and endocytotic events can be controlled by light and that these photoinduced processes provide an attractive method to change membrane area and morphology.},
  language  = {en}
}
@article{AndresHankeBaxaetal.2010,
  author    = {Andres, Dorothee and Hanke, Christin and Baxa, Ulrich and Seul, Anait and Barbirz, Stefanie and Seckler, Robert},
  title     = {Tailspike interactions with lipopolysaccharide effect DNA ejection from phage P22 particles in vitro},
  issn      = {0021-9258},
  doi       = {10.1074/jbc.M110.169003},
  year      = {2010},
  abstract  = {Initial attachment of bacteriophage P22 to the Salmonella host cell is known to be mediated by interactions between lipopolysaccharide (LPS) and the phage tailspike proteins (TSP), but the events that subsequently lead to DNA injection into the bacterium are unknown. We used the binding of a fluorescent dye and DNA accessibility to DNase and restriction enzymes to analyze DNA ejection from phage particles in vitro. Ejection was specifically triggered by aggregates of purified Salmonella LPS but not by LPS with different O-antigen structure, by lipid A, phospholipids, or soluble O-antigen polysaccharide. This suggests that P22 does not use a secondary receptor at the bacterial outer membrane surface. Using phage particles reconstituted with purified mutant TSP in vitro, we found that the endorhamnosidase activity of TSP degrading the O-antigen polysaccharide was required prior to DNA ejection in vitro and DNA replication in vivo. If, however, LPS was pre-digested with soluble TSP, it was no longer able to trigger DNA ejection, even though it still contained five O-antigen oligosaccharide repeats. Together with known data on the structure of LPS and phage P22, our results suggest a molecular model. In this model, tail-spikes position the phage particles on the outer membrane surface for DNA ejection. They force gp26, the central needle and plug protein of the phage tail machine, through the core oligosaccharide layer and into the hydrophobic portion of the outer membrane, leading to refolding of the gp26 lazo-domain, release of the plug, and ejection of DNA and pilot proteins.},
  language  = {en}
}
@article{AndresBaxaHankeetal.2010,
  author    = {Andres, Dorothee and Baxa, Ulrich and Hanke, Christin and Seckler, Robert and Barbirz, Stefanie},
  title     = {Carbohydrate binding of Salmonella phage P22 tailspike protein and its role during host cell infection},
  issn      = {0300-5127},
  doi       = {10.1042/Bst0381386},
  year      = {2010},
  abstract  = {TSPs (tailspike proteins) are essential infection organelles of bacteriophage P22. Upon infection, P22TSP binds to and cleaves the O-antigen moiety of the LPS (lipopolysaccharide) of its Salmonella host To elucidate the role of TSP during infection, we have studied binding to oligosaccharides and polysaccharides of Salmonella enteric Typhimurium and Enteritidis in vitro. P22TSP is a trimeric beta-helical protein with a carbohydrate-binding site on each subunit. Octasaccharide O-antigen fragments bind to P22TSP with micromolar dissociation constants. Moreover, P22TSP is an endorhamnosidase and cleaves the host O-antigen. Catalytic residues lie at the periphery of the high-affinity binding site, which enables unproductive binding modes, resulting in slow hydrolysis. However, the role of this hydrolysis function during infection remains unclear. Binding of polysaccharide to P22TSP is of high avidity with slow dissociation rates when compared with oligosaccharides. In vivo, the infection of Salmonella with phage P22 can be completely inhibited by the addition of LPS, indicating that binding of phage to its host via TSP is an essential step for infection.},
  language  = {en}
}
@article{BroekerRoskeVallerianietal.2019,
  author    = {Broeker, Nina K. and Roske, Yvette and Valleriani, Angelo and Stephan, Mareike Sophia and Andres, Dorothee and Koetz, Joachim and Heinemann, Udo and Barbirz, Stefanie},
  title     = {Time-resolved DNA release from an O-antigen-specific Salmonella bacteriophage with a contractile tail},
  series = {The journal of biological chemistry},
  volume    = {294},
  journal   = {The journal of biological chemistry},
  number    = {31},
  publisher = {American Society for Biochemistry and Molecular Biology},
  address   = {Bethesda},
  issn      = {1083-351X},
  doi       = {10.1074/jbc.RA119.008133},
  pages     = {11751 -- 11761},
  year      = {2019},
  abstract  = {Myoviruses, bacteriophages with T4-like architecture, must contract their tails prior to DNA release. However, quantitative kinetic data on myovirus particle opening are lacking, although they are promising tools in bacteriophage-based antimicrobial strategies directed against Gram-negative hosts. For the first time, we show time-resolved DNA ejection from a bacteriophage with a contractile tail, the multi-O-antigen-specific Salmonella myovirus Det7. DNA release from Det7 was triggered by lipopolysaccharide (LPS) O-antigen receptors and notably slower than in noncontractile-tailed siphoviruses. Det7 showed two individual kinetic steps for tail contraction and particle opening. Our in vitro studies showed that highly specialized tailspike proteins (TSPs) are necessary to attach the particle to LPS. A P22-like TSP confers specificity for the Salmonella Typhimurium O-antigen. Moreover, crystal structure analysis at 1.63 angstrom resolution confirmed that Det7 recognized the Salmonella Anatum O-antigen via an E15-like TSP, DettilonTSP. DNA ejection triggered by LPS from either host showed similar velocities, so particle opening is thus a process independent of O-antigen composition and the recognizing TSP. In Det7, at permissive temperatures TSPs mediate O-antigen cleavage and couple cell surface binding with DNA ejection, but no irreversible adsorption occurred at low temperatures. This finding was in contrast to short-tailed Salmonella podoviruses, illustrating that tailed phages use common particle-opening mechanisms but have specialized into different infection niches.},
  language  = {en}
}
@inproceedings{StephanBarbirzRobinsonetal.2021,
  author    = {Stephan, Mareike Sophia and Barbirz, Stefanie and Robinson, Tom and Yandrapalli, Naresh and Dimova, Rumiana},
  title     = {Bacterial mimetic systems for studying bacterial inactivation and infection},
  series = {Biophysical journal : BJ / ed. by the Biophysical Society},
  volume    = {120},
  booktitle = {Biophysical journal : BJ / ed. by the Biophysical Society},
  number    = {3},
  publisher = {Cell Press},
  address   = {Cambridge},
  issn      = {0006-3495},
  doi       = {10.1016/j.bpj.2020.11.1087},
  pages     = {148A -- 148A},
  year      = {2021},
  language  = {en}
}
@article{StephanBroekerSaragliadisetal.2020,
  author    = {Stephan, Mareike Sophia and Br{\"o}ker, Nina K. and Saragliadis, Athanasios and Roos, Norbert and Linke, Dirk and Barbirz, Stefanie},
  title     = {In vitro analysis of O-antigen-specific bacteriophage P22 inactivation by Salmonella outer membrane vesicles},
  series = {Frontiers in microbiology},
  volume    = {11},
  journal   = {Frontiers in microbiology},
  publisher = {Frontiers Media},
  address   = {Lausanne},
  issn      = {1664-302X},
  doi       = {10.3389/fmicb.2020.510638},
  pages     = {12},
  year      = {2020},
  abstract  = {Bacteriophages use a large number of different bacterial cell envelope structures as receptors for surface attachment. As a consequence, bacterial surfaces represent a major control point for the defense against phage attack. One strategy for phage population control is the production of outer membrane vesicles (OMVs). In Gram-negative host bacteria, O-antigen-specific bacteriophages address lipopolysaccharide (LPS) to initiate infection, thus relying on an essential outer membrane glycan building block as receptor that is constantly present also in OMVs. In this work, we have analyzed interactions ofSalmonella(S.) bacteriophage P22 with OMVs. For this, we isolated OMVs that were formed in large amounts during mechanical cell lysis of the P22 S. Typhimurium host.In vitro, these OMVs could efficiently reduce the number of infective phage particles. Fluorescence spectroscopy showed that upon interaction with OMVs, bacteriophage P22 released its DNA into the vesicle lumen. However, only about one third of the phage P22 particles actively ejected their genome. For the larger part, no genome release was observed, albeit the majority of phages in the system had lost infectivity towards their host. With OMVs, P22 ejected its DNA more rapidly and could release more DNA against elevated osmotic pressures compared to DNA release triggered with protein-free LPS aggregates. This emphasizes that OMV composition is a key feature for the regulation of infective bacteriophage particles in the system.},
  language  = {en}
}
@article{KangGohlkeEngstroemetal.2016,
  author    = {Kang, Yu and Gohlke, Ulrich and Engstr{\"o}m, Olof and Hamark, Christoffer and Scheidt, Tom and Kunstmann, Ruth Sonja and Heinemann, Udo and Widmalm, G{\"o}ran and Santer, Mark and Barbirz, Stefanie},
  title     = {Bacteriophage Tailspikes and Bacterial O-Antigens as a Model System to Study Weak-Affinity Protein-Polysaccharide Interactions},
  series = {Journal of the American Chemical Society},
  volume    = {138},
  journal   = {Journal of the American Chemical Society},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {0002-7863},
  doi       = {10.1021/jacs.6b00240},
  pages     = {9109 -- 9118},
  year      = {2016},
  abstract  = {Understanding interactions of bacterial surface polysaccharides with receptor protein scaffolds is important for the development of antibiotic therapies. The corresponding protein recognition domains frequently form low-affinity complexes with polysaccharides that are difficult to address with experimental techniques due to the conformational flexibility of the polysaccharide. In this work, we studied the tailspike protein (TSP) of the bacteriophage Sf6. Sf6TSP binds and hydrolyzes the high-rhamnose, serotype Y O-antigen polysaccharide of the Gram-negative bacterium Shigella flexneri (S. flexneri) as a first step of bacteriophage infection. Spectroscopic analyses and enzymatic cleavage assays confirmed that Sf6TSP binds long stretches of this polysaccharide. Crystal structure analysis and saturation transfer difference (STD) NMR spectroscopy using an enhanced method to interpret the data permitted the detailed description of affinity contributions and flexibility in an Sf6TSP-octasaccharide complex. Dodecasaccharide fragments corresponding to three repeating units of the O-antigen in complex with Sf6TSP were studied computationally by molecular dynamics simulations. They showed that distortion away from the low-energy solution conformation found in the octasaccharide complex is necessary for ligand binding. This is in agreement with a weak-affinity functional polysaccharide protein contact that facilitates correct placement and thus hydrolysis of the polysaccharide close to the catalytic residues. Our simulations stress that the flexibility of glycan epitopes together with a small number of specific protein contacts provide the driving force for Sf6TSP-polysaccharide complex formation in an overall weak-affinity interaction system.},
  language  = {en}
}
@inproceedings{KangBarbirzGohlkeetal.2014,
  author    = {Kang, Yu and Barbirz, Stefanie and Gohlke, Ulrich and Santer, Mark},
  title     = {Molecular dynamics study on the interaction of O-antigen polysaccharides of the gram-negative bacterium Shigella flexneri with the tail-spike-protein of bacteriophage Sf6},
  series = {Abstracts of papers : joint conference / The Chemical Institute of Cananda, CIC, American Chemical Society, ACS},
  volume    = {248},
  booktitle = {Abstracts of papers : joint conference / The Chemical Institute of Cananda, CIC, American Chemical Society, ACS},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {0065-7727},
  pages     = {1},
  year      = {2014},
  language  = {en}
}
@article{KangBarbirzLipowskyetal.2014,
  author    = {Kang, Yu and Barbirz, Stefanie and Lipowsky, Reinhard and Santer, Mark},
  title     = {Conformational Diversity of O-Antigen Polysaccharides of the Gram-Negative Bacterium Shigella flexneri Serotype Y},
  series = {The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces \& biophysical chemistry},
  volume    = {118},
  journal   = {The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces \& biophysical chemistry},
  number    = {9},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1520-6106},
  doi       = {10.1021/jp4111713},
  pages     = {2523 -- 2534},
  year      = {2014},
  language  = {en}
}
@inproceedings{KangBarbirzLipowskyetal.2013,
  author    = {Kang, Y. and Barbirz, Stefanie and Lipowsky, Reinhard and Santer, Mark},
  title     = {Conformational Insights into Recognition Mechanism of O-Antigen Polysaccharides by Tailspike Protein},
  series = {European biophysics journal : with biophysics letters ; an international journal of biophysics},
  volume    = {42},
  booktitle = {European biophysics journal : with biophysics letters ; an international journal of biophysics},
  number    = {1},
  publisher = {Springer},
  address   = {New York},
  issn      = {0175-7571},
  pages     = {S112 -- S112},
  year      = {2013},
  language  = {en}
}
@misc{KunstmannEngstroemWehleetal.2020,
  author    = {Kunstmann, Ruth Sonja and Engstr{\"o}m, Olof and Wehle, Marko and Widmalm, G{\"o}ran and Santer, Mark and Barbirz, Stefanie},
  title     = {Increasing the affinity of an O-Antigen polysaccharide binding site in Shigella flexneri bacteriophage Sf6 tailspike protein},
  series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {32},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-51941},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-519418},
  pages     = {13},
  year      = {2020},
  abstract  = {Broad and unspecific use of antibiotics accelerates spread of resistances. Sensitive and robust pathogen detection is thus important for a more targeted application. Bacteriophages contain a large repertoire of pathogen-binding proteins. These tailspike proteins (TSP) often bind surface glycans and represent a promising design platform for specific pathogen sensors. We analysed bacteriophage Sf6 TSP that recognizes the O-polysaccharide of dysentery-causing Shigella flexneri to develop variants with increased sensitivity for sensor applications. Ligand polyrhamnose backbone conformations were obtained from 2D H-1,H-1-trNOESY NMR utilizing methine-methine and methine-methyl correlations. They agreed well with conformations obtained from molecular dynamics (MD), validating the method for further predictions. In a set of mutants, MD predicted ligand flexibilities that were in good correlation with binding strength as confirmed on immobilized S. flexneri O-polysaccharide (PS) with surface plasmon resonance. In silico approaches combined with rapid screening on PS surfaces hence provide valuable strategies for TSP-based pathogen sensor design.},
  language  = {en}
}
@article{KunstmannEngstroemWehleetal.2020,
  author    = {Kunstmann, Ruth Sonja and Engstr{\"o}m, Olof and Wehle, Marko and Widmalm, G{\"o}ran and Santer, Mark and Barbirz, Stefanie},
  title     = {Increasing the affinity of an O-Antigen polysaccharide binding site in Shigella flexneri bacteriophage Sf6 tailspike protein},
  series = {Chemistry - A European Journal},
  volume    = {26},
  journal   = {Chemistry - A European Journal},
  number    = {32},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {0947-6539},
  doi       = {10.1002/chem.202000495},
  pages     = {7263 -- 7273},
  year      = {2020},
  abstract  = {Broad and unspecific use of antibiotics accelerates spread of resistances. Sensitive and robust pathogen detection is thus important for a more targeted application. Bacteriophages contain a large repertoire of pathogen-binding proteins. These tailspike proteins (TSP) often bind surface glycans and represent a promising design platform for specific pathogen sensors. We analysed bacteriophage Sf6 TSP that recognizes the O-polysaccharide of dysentery-causing Shigella flexneri to develop variants with increased sensitivity for sensor applications. Ligand polyrhamnose backbone conformations were obtained from 2D H-1,H-1-trNOESY NMR utilizing methine-methine and methine-methyl correlations. They agreed well with conformations obtained from molecular dynamics (MD), validating the method for further predictions. In a set of mutants, MD predicted ligand flexibilities that were in good correlation with binding strength as confirmed on immobilized S. flexneri O-polysaccharide (PS) with surface plasmon resonance. In silico approaches combined with rapid screening on PS surfaces hence provide valuable strategies for TSP-based pathogen sensor design.},
  language  = {en}
}