@article{BoboneHilschStormetal.2017, author = {Bobone, Sara and Hilsch, Malte and Storm, Julian and Dunsing, Valentin and Herrmann, Andreas and Chiantia, Salvatore}, title = {Phosphatidylserine Lateral Organization Influences the Interaction of Influenza Virus Matrix Protein 1 with Lipid Membranes}, series = {Journal of virology}, volume = {91}, journal = {Journal of virology}, publisher = {American Society for Microbiology}, address = {Washington}, issn = {0022-538X}, doi = {10.1128/JVI.00267-17}, pages = {15}, year = {2017}, abstract = {Influenza A virus matrix protein 1 (M1) is an essential component involved in the structural stability of the virus and in the budding of new virions from infected cells. A deeper understanding of the molecular basis of virion formation and the budding process is required in order to devise new therapeutic approaches. We performed a detailed investigation of the interaction between M1 and phosphatidylserine (PS) (i.e., its main binding target at the plasma membrane [PM]), as well as the distribution of PS itself, both in model membranes and in living cells. To this end, we used a combination of techniques, including Forster resonance energy transfer (FRET), confocal microscopy imaging, raster image correlation spectroscopy, and number and brightness (N\&B) analysis. Our results show that PS can cluster in segregated regions in the plane of the lipid bilayer, both in model bilayers constituted of PS and phosphatidylcholine and in living cells. The viral protein M1 interacts specifically with PS-enriched domains, and such interaction in turn affects its oligomerization process. Furthermore, M1 can stabilize PS domains, as observed in model membranes. For living cells, the presence of PS clusters is suggested by N\&B experiments monitoring the clustering of the PS sensor lactadherin. Also, colocalization between M1 and a fluorescent PS probe suggest that, in infected cells, the matrix protein can specifically bind to the regions of PM in which PS is clustered. Taken together, our observations provide novel evidence regarding the role of PS-rich domains in tuning M1-lipid and M1-M1 interactions at the PM of infected cells. IMPORTANCE Influenza virus particles assemble at the plasma membranes (PM) of infected cells. This process is orchestrated by the matrix protein M1, which interacts with membrane lipids while binding to the other proteins and genetic material of the virus. Despite its importance, the initial step in virus assembly (i.e., M1-lipid interaction) is still not well understood. In this work, we show that phosphatidylserine can form lipid domains in physical models of the inner leaflet of the PM. Furthermore, the spatial organization of PS in the plane of the bilayer modulates M1-M1 interactions. Finally, we show that PS domains appear to be present in the PM of living cells and that M1 seems to display a high affinity for them.}, language = {en} } @article{DunsingLucknerZuehlkeetal.2018, author = {Dunsing, Valentin and Luckner, Madlen and Zuehlke, Boris and Petazzi, Roberto Arturo and Herrmann, Andreas and Chiantia, Salvatore}, title = {Optimal fluorescent protein tags for quantifying protein oligomerization in living cells}, series = {Scientific reports}, volume = {8}, journal = {Scientific reports}, publisher = {Nature Publ. Group}, address = {London}, issn = {2045-2322}, doi = {10.1038/s41598-018-28858-0}, pages = {12}, year = {2018}, abstract = {Fluorescence fluctuation spectroscopy has become a popular toolbox for non-disruptive analysis of molecular interactions in living cells. The quantification of protein oligomerization in the native cellular environment is highly relevant for a detailed understanding of complex biological processes. An important parameter in this context is the molecular brightness, which serves as a direct measure of oligomerization and can be easily extracted from temporal or spatial fluorescence fluctuations. However, fluorescent proteins (FPs) typically used in such studies suffer from complex photophysical transitions and limited maturation, inducing non-fluorescent states. Here, we show how these processes strongly affect molecular brightness measurements. We perform a systematic characterization of non-fluorescent states for commonly used FPs and provide a simple guideline for accurate, unbiased oligomerization measurements in living cells. Further, we focus on novel red FPs and demonstrate that mCherry2, an mCherry variant, possesses superior properties with regards to precise quantification of oligomerization.}, language = {en} } @article{GoetzSuopankiSchuleretal.2005, author = {Goetz, C. and Suopanki, J. and Schuler, Benjamin and Wanker, E. and Herrmann, Andreas}, title = {Perturbation of brain lipid membrane by soluble Huntingtin depends on its polyproline tract}, issn = {0006-3495}, year = {2005}, language = {en} } @article{GrimmMeyerCzaplaetal.2013, author = {Grimm, Christiane and Meyer, Thomas and Czapla, Sylvia and Nikolaus, J{\"o}rg and Scheidt, Holger A. and Vogel, Alexander and Herrmann, Andreas and Wessig, Pablo and Huster, Daniel and M{\"u}ller, Peter}, title = {Structure and dynamics of molecular rods in membranes application of a Spin-Labeled rod}, series = {Chemistry - a European journal}, volume = {19}, journal = {Chemistry - a European journal}, number = {8}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0947-6539}, doi = {10.1002/chem.201202500}, pages = {2703 -- 2710}, year = {2013}, abstract = {Molecular rods consisting of a hydrophobic backbone and terminally varying functional groups have been synthesized for applications for the functionalization of membranes. In the present study, we employ a spin-labeled analogue of a recently described new class of molecular rods to characterize their dynamic interactions with membranes. By using the different approaches of ESR and NMR spectroscopy, we show that the spin moiety of the membrane-embedded spin-labeled rod is localized in the upper chain/glycerol region of membranes of different compositions. The rod is embedded within the membrane in a tilted orientation to adjust for the varying hydrophobic thicknesses of these bilayers. This orientation does not perturb the membrane structure. The water solubility of the rod is increased significantly in the presence of certain cyclodextrins. These cyclodextrins also allow the rods to be extracted from the membrane and incorporated into preformed membranes. The latter will improve the future applications of these rods in cellular systems as stable membrane-associated anchors for the functionalization of membrane surfaces.}, language = {en} } @article{HaralampievMertensSchwarzeretal.2015, author = {Haralampiev, Ivan and Mertens, Monique and Schwarzer, Roland and Herrmann, Andreas and Volkmer, Rudolf and Wessig, Pablo and Mueller, Peter}, title = {Recruitment of SH-Containing peptides to lipid and biological membranes through the use of a palmitic acid functionalized with a Maleimide Group}, series = {Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition}, volume = {54}, journal = {Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition}, number = {1}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1433-7851}, doi = {10.1002/anie.201408089}, pages = {323 -- 326}, year = {2015}, abstract = {This study presents a novel and easily applicable approach to recruit sulfhydryl-containing biomolecules to membranes by using a palmitic acid which is functionalized with a maleimide group. Notably, this strategy can also be employed with preformed (biological) membranes. The applicability of the assay is demonstrated by characterizing the binding of a Rhodamine-labeled peptide to lipid and cellular membranes using methods of fluorescence spectroscopy, lifetime measurement, and microscopy. Our approach offers new possibilities for preparing biologically active liposomes and manipulating living cells.}, language = {en} } @inproceedings{HaralampievMertensSchwarzeretal.2015, author = {Haralampiev, Ivan and Mertens, Monique and Schwarzer, Roland and Herrmann, Andreas and Volkmer, Rudolf and Wessig, Pablo and M{\"u}ller, Peter}, title = {A palmitic acid functionalized with a maleimide group is used to recruit SH-containing peptides to lipid and biological membranes}, series = {The FEBS journal}, volume = {282}, booktitle = {The FEBS journal}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {1742-464X}, pages = {204 -- 204}, year = {2015}, language = {en} } @article{HeuvelingFrochauxZiomkowskaetal.2014, author = {Heuveling, Johanna and Frochaux, Violette and Ziomkowska, Joanna and Wawrzinek, Robert and Wessig, Pablo and Herrmann, Andreas and Schneider, Erwin}, title = {Conformational changes of the bacterial type I ATP-binding cassette importer HisQMP(2) at distinct steps of the catalytic cycle}, series = {Biochimica et biophysica acta : Biomembranes}, volume = {1838}, journal = {Biochimica et biophysica acta : Biomembranes}, number = {1}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0005-2736}, doi = {10.1016/j.bbamem.2013.08.024}, pages = {106 -- 116}, year = {2014}, abstract = {Prokaryotic solute binding protein-dependent ATP-binding cassette import systems are divided into type land type II and mechanistic differences in the transport process going along with this classification are under intensive investigation. Little is known about the conformational dynamics during the catalytic cycle especially concerning the transmembrane domains. The type I transporter for positively charged amino acids from Salmonella enterica serovar Typhimurium (1A0-Hi5QMP2) was studied by limited proteolysis in detergent solution in the absence and presence of co-factors including ATP, ADP, LAO/arginine, and Mg2+ ions. Stable peptide fragments could be obtained and differentially susceptible cleavage sites were determined by mass spectrometry as Lys-258 in the nucleotide-binding subunit, HisP, and Arg-217/Arg-218 in the transmembrane subunit, HisQ In contrast, transmembrane subunit HisM was gradually degraded but no stable fragment could be detected. HisP and HisQ were equally resistant under pre- and post-hydrolysis conditions in the presence of arginine-loaded solute-binding protein LAO and ATP/ADP. Some protection was also observed with LAO/arginine alone, thus reflecting binding to the transporter in the apo-state and transmembrane signaling. Comparable digestion patterns were obtained with the transporter reconstituted into proteoliposomes and nanodiscs. Fluorescence lifetime spectroscopy confirmed the change of HisQ(R218) to a more apolar microenvironment upon ATP binding and hydrolysis. Limited proteolysis was subsequently used as a tool to study the consequences of mutations on the transport cycle. Together, our data suggest similar conformational changes during the transport cycle as described for the maltose ABC transporter of Escherichia coli, despite distinct structural differences between both systems.}, language = {en} } @article{KloseGuillemoteauVignolietal.2023, author = {Klose, Tim and Guillemoteau, Julien and Vignoli, Giulio and Walter, Judith and Herrmann, Andreas and Tronicke, Jens}, title = {Structurally constrained inversion by means of a Minimum Gradient Support regularizer: examples of FD-EMI data inversion constrained by GPR reflection data}, series = {Geophysical journal international}, volume = {233}, journal = {Geophysical journal international}, number = {3}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {0956-540X}, doi = {10.1093/gji/ggad041}, pages = {1938 -- 1949}, year = {2023}, abstract = {Many geophysical inverse problems are known to be ill-posed and, thus, requiring some kind of regularization in order to provide a unique and stable solution. A possible approach to overcome the inversion ill-posedness consists in constraining the position of the model interfaces. For a grid-based parameterization, such a structurally constrained inversion can be implemented by adopting the usual smooth regularization scheme in which the local weight of the regularization is reduced where an interface is expected. By doing so, sharp contrasts are promoted at interface locations while standard smoothness constraints keep affecting the other regions of the model. In this work, we present a structurally constrained approach and test it on the inversion of frequency-domain electromagnetic induction (FD-EMI) data using a regularization approach based on the Minimum Gradient Support stabilizer, which is capable to promote sharp transitions everywhere in the model, i.e., also in areas where no structural a prioriinformation is available. Using 1D and 2D synthetic data examples, we compare the proposed approach to a structurally constrained smooth inversion as well as to more standard (i.e., not structurally constrained) smooth and sharp inversions. Our results demonstrate that the proposed approach helps in finding a better and more reliable reconstruction of the subsurface electrical conductivity distribution, including its structural characteristics. Furthermore, we demonstrate that it allows to promote sharp parameter variations in areas where no structural information are available. Lastly, we apply our structurally constrained scheme to FD-EMI field data collected at a field site in Eastern Germany to image the thickness of peat deposits along two selected profiles. In this field example, we use collocated constant offset ground-penetrating radar (GPR) data to derive structural a priori information to constrain the inversion of the FD-EMI data. The results of this case study demonstrate the effectiveness and flexibility of the proposed approach.}, language = {en} } @misc{LucknerDunsingChiantiaetal.2017, author = {Luckner, Madlen and Dunsing, Valentin and Chiantia, Salvatore and Herrmann, Andreas}, title = {Influenza virus vRNPs: quantitative investigations via fluorescence cross-correlation spectroscopy}, series = {European biophysics journal : with biophysics letters ; an international journal of biophysics}, volume = {46}, journal = {European biophysics journal : with biophysics letters ; an international journal of biophysics}, publisher = {Springer}, address = {New York}, issn = {0175-7571}, pages = {S368 -- S368}, year = {2017}, language = {en} } @inproceedings{MemczakLausterHerrmannetal.2013, author = {Memczak, Henry and Lauster, Daniel and Herrmann, Andreas and St{\"o}cklein, Walter F. M. and Bier, Frank Fabian}, title = {Novel hemagglutinin-binding peptides for biosensing and inhibition of Influenza Viruses}, series = {Biopolymers}, volume = {100}, booktitle = {Biopolymers}, number = {3}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0006-3525}, pages = {255 -- 255}, year = {2013}, language = {en} }