@article{FolikumahBehlLendlein2021, author = {Folikumah, Makafui Y. and Behl, Marc and Lendlein, Andreas}, title = {Reaction behaviour of peptide-based single thiol-thioesters exchange reaction substrate in the presence of externally added thiols}, series = {MRS communications / a publication of the Materials Research Society}, volume = {11}, journal = {MRS communications / a publication of the Materials Research Society}, number = {4}, publisher = {Springer}, address = {Berlin}, issn = {2159-6859}, doi = {10.1557/s43579-021-00041-z}, pages = {402 -- 410}, year = {2021}, abstract = {Identification of patterns in chemical reaction pathways aids in the effective design of molecules for specific applications. Here, we report on model reactions with a water-soluble single thiol-thioester exchange (TTE) reaction substrate, which was designed taking in view biological and medical applications. This substrate consists of the thio-depsipeptide, Ac-Pro-Leu-Gly-SLeu-Leu-Gly-NEtSH (TDP) and does not yield foul-smelling thiol exchange products when compared with aromatic thiol containing single TTE substrates. TDP generates an alpha,omega-dithiol crosslinker in situ in a 'pseudo intramolecular' TTE. Competitive intermolecular TTE of TDP with externally added "basic" thiols increased the crosslinker concentration whilst "acidic" thiols decreased its concentration. TDP could potentially enable in situ bioconjugation and crosslinking applications.}, language = {en} } @article{UhrWielandHomannetal.2016, author = {Uhr, Linda and Wieland, Phillis and Homann, Thomas and Huschek, Gerd and Rawel, Harshadrai Manilal}, title = {Identification and LC-MS/MS-based analyses of technical enzymes in wheat flour and baked products}, series = {European food research and technology : official organ of the EuCheMS, Division of Food Chemistry}, volume = {242}, journal = {European food research and technology : official organ of the EuCheMS, Division of Food Chemistry}, publisher = {Springer}, address = {New York}, issn = {1438-2377}, doi = {10.1007/s00217-015-2536-5}, pages = {247 -- 257}, year = {2016}, abstract = {The use of technical enzymes in bakery industry is necessary for a consistent and good quality of baked products. Since the cultivation of cereals leads to low amounts of endogenous enzymes being present, a need of their commercial alternatives is becoming a routine process in order to meet the consumer quality demands. Targeted quantification proteomics-based methods are necessary for their detection to meet the regulatory criteria. Here, we initially report on the identification of Lipase FE-01, a lipase from fungus Thermomyces lanuginosus, as analyzed by SDS-PAGE, in-Gel digestion, and MALDI-TOF-MS. In further experiments, the focus of the study was directed toward an extensive use and optimization of in-solution enzymatic digestion in combination with LC-MS/MS techniques in identification of specific peptide markers and finally in utilization of the latter in delivering reproducible quantification data for several different technical enzymes (alpha-amylases, xylanase, and lipases from microbial origin) in complex matrices such as baked bread and wheat flour. Two digestion protocols (a fast option using thermocycler program and the well-established overnight method) were tested, and both of these can be successfully applied. The application of isotopically labeled analogs of the MRM targeted peptides as internal standards and the addition of an internal protein standard during the extraction/digestion experiment were compared to determine the optimal quantification algorithm of the recovered enzyme concentrations. Thus, a standardized sensitive LC-MS/MS method could be developed to determine technical enzymes as forthcoming ingredients in the prefabricated food formulations in concentrations lower than 10 ppm.}, language = {en} } @article{ReichelHoenigLiebischetal.2015, author = {Reichel, Martin and Hoenig, Stefanie and Liebisch, Gerhard and L{\"u}th, Anja and Kleuser, Burkhard and Gulbins, Erich and Schmitz, Gerd and Kornhuber, Johannes}, title = {Alterations of plasma glycerophospholipid and sphingolipid species in male alcohol-dependent patients}, series = {Biochimica et biophysica acta : Molecular and cell biology of lipids}, volume = {1851}, journal = {Biochimica et biophysica acta : Molecular and cell biology of lipids}, number = {11}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1388-1981}, doi = {10.1016/j.bbalip.2015.08.005}, pages = {1501 -- 1510}, year = {2015}, abstract = {Background: Alcohol abuse is a major risk factor for somatic and neuropsychiatric diseases. Despite their potential clinical importance, little is known about the alterations of plasma glycerophospholipid (GPL) and sphingolipid (SPL) species associated with alcohol abuse. Methods: Plasma GPL and SPL species were quantified using electrospray ionization tandem mass spectrometry in samples from 23 male alcohol-dependent patients before and after detoxification, as well as from 20 healthy male controls. Results: A comparison of alcohol-dependent patients with controls revealed higher phosphatidylcholine (PC; P-value = 0.008) and phosphatidylinositol (PI; P-value = 0.001) concentrations in patients before detoxification, and higher PI (P-value = 0.001) and phosphatidylethanolamine (PE)-based plasmalogen (PEP; P-value = 0.003) concentrations after detoxification. Lysophosphatidylcholines (LPC) were increased by acute intoxication (P-value = 0.002). Sphingomyelin (SM) concentration increased during detoxification (P-value = 0.011). The concentration of SM 23:0 was lower in patients (P-value = 2.79 x 10(-5)), and the concentrations of ceramide Cer d18:1/16:0 and Cer d18:1/18:0 were higher in patients (P-value = 2.45 x 10(-5) and 3.73 x 10(-5)). Activity of lysosomal acid sphingomyelinase (ASM) in patients correlated positively with the concentrations of eight LPC species, while activity of secreted ASM was inversely correlated with several PE, PI and PC species, and positively correlated with the molar ratio of PC to SM (Pearson's r = 0.432; P-value = 0.039). Conclusion: Plasma concentrations of numerous GPL and SPL species were altered in alcohol-dependent patients. These molecules might serve as potential biomarkers to improve the diagnosis of patients and to indicate health risks associated with alcohol abuse. Our study further indicates that there are strong interactions between plasma GPL concentrations and SPL metabolism. (C) 2015 Elsevier B.V. All rights reserved.}, language = {en} } @article{UhrBuchholzHomannetal.2014, author = {Uhr, Linda and Buchholz, Tina and Homann, Thomas and Huschek, Gerd and Rawel, Harshadrai Manilal}, title = {Targeted proteomics-based analysis of technical enzymes from fungal origin in baked products}, series = {Journal of cereal science}, volume = {60}, journal = {Journal of cereal science}, number = {2}, publisher = {Elsevier}, address = {London}, issn = {0733-5210}, doi = {10.1016/j.jcs.2014.04.007}, pages = {440 -- 447}, year = {2014}, abstract = {The application of technical enzymes is a potential tool in modulating the dough and baking quality of cereal products. No endogenous amylases (alpha- and beta-forms) are present in mature wheat grains; they may be synthesized or activated during germination. Hence, microbial alpha-amylases are added to the dough, being resistant to the endogenous alpha-amylase/trypsin inhibitors. Here, we report on the initial identification of two technical enzymes from a commercial sample based on an in-gel tryptic digestion coupled with MALDI-MS analysis. The primary component of the protein fraction with 51.3 kDa was alpha-amylase from Aspergillus species. A second major protein with 24.8 kDa was identified as endo-1,4-xylanase from Thermomyces lanuginosus. In the following experimental work up, a targeted proteomics approach utilizing the combination of specific proteolytic digestion of the added amylase and xylanase in wheat flour, dough or baked products, solid phase extraction of released peptides and their detection using LC-MS/MS was optimized. The targeted (MRM) MS/MS peptide signals showed that the peptide "ALSSALHER" (MW = 983) originating from amylase and "GWNPGLNAR" (MW = 983) from xylanase can be used to identify the corresponding technical enzymes added. Consequently, locally available baked products were tested and found to contain these enzymes as supplementary ingredients. (C) 2014 Elsevier Ltd. All rights reserved.}, language = {en} } @article{BrendlerRiebeRitscheletal.2013, author = {Brendler, Christian and Riebe, Daniel and Ritschel, Thomas and Beitz, Toralf and L{\"o}hmannsr{\"o}ben, Hans-Gerd}, title = {Investigation of neuroleptics and other aromatic compounds by laser-based ion mobility mass spectrometry}, series = {Analytical \& bioanalytical chemistry}, volume = {405}, journal = {Analytical \& bioanalytical chemistry}, number = {22}, publisher = {Springer}, address = {Heidelberg}, issn = {1618-2642}, doi = {10.1007/s00216-012-6654-7}, pages = {7019 -- 7029}, year = {2013}, abstract = {Laser-based ion mobility (IM) spectrometry was used for the detection of neuroleptics and PAH. A gas chromatograph was connected to the IM spectrometer in order to investigate compounds with low vapour pressure. The substances were ionized by resonant two-photon ionization at the wavelengths lambda = 213 and 266 nm and pulse energies between 50 and 300 mu J. Ion mobilities, linear ranges, limits of detection and response factors are reported. Limits of detection for the substances are in the range of 1-50 fmol. Additionally, the mechanism of laser ionization at atmospheric pressure was investigated. First, the primary product ions were determined by a laser-based time-of-flight mass spectrometer with effusive sample introduction. Then, a combination of a laser-based IM spectrometer and an ion trap mass spectrometer was developed and characterized to elucidate secondary ion-molecule reactions that can occur at atmospheric pressure. Some substances, namely naphthalene, anthracene, promazine and thioridazine, could be detected as primary ions (radical cations), while other substances, in particular acridine, phenothiazine and chlorprothixene, are detected as secondary ions (protonated molecules). The results are interpreted on the basis of quantum chemical calculations, and an ionization mechanism is proposed.}, language = {en} } @article{RiebeLaudienBrendleretal.2013, author = {Riebe, Daniel and Laudien, Robert and Brendler, Christian and Beitz, Toralf and L{\"o}hmannsr{\"o}ben, Hans-Gerd}, title = {Laser ionization of H2S and ion-molecule reactions of H3S+ in laser-based ion mobility spectrometry and drift cell time-of-flight mass spectrometry}, series = {Analytical \& bioanalytical chemistry}, volume = {405}, journal = {Analytical \& bioanalytical chemistry}, number = {22}, publisher = {Springer}, address = {Heidelberg}, issn = {1618-2642}, doi = {10.1007/s00216-013-7186-5}, pages = {7031 -- 7039}, year = {2013}, abstract = {The detection of hydrogen sulfide (H2S) by 2 + 1 resonance-enhanced multi-photon ionization (REMPI) and the application of H2S as a laser dopant for the detection of polar compounds in laser ion mobility (IM) spectrometry at atmospheric pressure were investigated. Underlying ionization mechanisms were elucidated by additional studies employing a drift cell interfaced to a time-of-flight mass spectrometer. Depending on the pressure, the primary ions H2S+, HS+, S+, and secondary ions, such as H3S+, were observed. The 2 + 1 REMPI spectrum of H2S near lambda = 302.5 nm was recorded at atmospheric pressure. Furthermore, the limit of detection and the linear range were established. In the second part of the work, H2S was investigated as an H2O analogous laser dopant for the ionization of polar substances by proton transfer. H2S exhibits a proton affinity (PA) similar to that of H2O, but a significantly lower ionization energy facilitating laser ionization. Ion-molecule reactions (IMR) of H3S+ with a variety of polar substances with PA between 754.6 and 841.6 kJ/mol were investigated. Representatives of different compound classes, including alcohols, ketones, esters, and nitroaromatics were analyzed. The IM spectra resulting from IMR of H3S+ and H3O+ with these substances are similar in structure, i.e., protonated monomer and dimer ion peaks are found depending on the analyte concentration.}, language = {en} } @article{SramaKruegerYamaguchietal.2012, author = {Srama, Ralf and Krueger, H. and Yamaguchi, T. and Stephan, T. and Burchell, M. and Kearsley, A. T. and Sterken, V. and Postberg, F. and Kempf, S. and Gr{\"u}n, Eberhard and Altobelli, Nicolas and Ehrenfreund, P. and Dikarev, V. and Horanyi, M. and Sternovsky, Zoltan and Carpenter, J. D. and Westphal, A. and Gainsforth, Z. and Krabbe, A. and Agarwal, Jessica and Yano, H. and Blum, J. and Henkel, H. and Hillier, J. and Hoppe, P. and Trieloff, M. and Hsu, S. and Mocker, A. and Fiege, K. and Green, S. F. and Bischoff, A. and Esposito, F. and Laufer, R. and Hyde, T. W. and Herdrich, G. and Fasoulas, S. and Jaeckel, A. and Jones, G. and Jenniskens, P. and Khalisi, E. and Moragas-Klostermeyer, Georg and Spahn, Frank and Keller, H. U. and Frisch, P. and Levasseur-Regourd, A. C. and Pailer, N. and Altwegg, K. and Engrand, C. and Auer, S. and Silen, J. and Sasaki, S. and Kobayashi, M. and Schmidt, J. and Kissel, J. and Marty, B. and Michel, P. and Palumbo, P. and Vaisberg, O. and Baggaley, J. and Rotundi, A. and Roeser, H. P.}, title = {SARIM PLUS-sample return of comet 67P/CG and of interstellar matter}, series = {EXPERIMENTAL ASTRONOMY}, volume = {33}, journal = {EXPERIMENTAL ASTRONOMY}, number = {2-3}, publisher = {SPRINGER}, address = {DORDRECHT}, issn = {0922-6435}, doi = {10.1007/s10686-011-9285-7}, pages = {723 -- 751}, year = {2012}, abstract = {The Stardust mission returned cometary, interplanetary and (probably) interstellar dust in 2006 to Earth that have been analysed in Earth laboratories worldwide. Results of this mission have changed our view and knowledge on the early solar nebula. The Rosetta mission is on its way to land on comet 67P/Churyumov-Gerasimenko and will investigate for the first time in great detail the comet nucleus and its environment starting in 2014. Additional astronomy and planetary space missions will further contribute to our understanding of dust generation, evolution and destruction in interstellar and interplanetary space and provide constraints on solar system formation and processes that led to the origin of life on Earth. One of these missions, SARIM-PLUS, will provide a unique perspective by measuring interplanetary and interstellar dust with high accuracy and sensitivity in our inner solar system between 1 and 2 AU. SARIM-PLUS employs latest in-situ techniques for a full characterisation of individual micrometeoroids (flux, mass, charge, trajectory, composition()) and collects and returns these samples to Earth for a detailed analysis. The opportunity to visit again the target comet of the Rosetta mission 67P/Churyumov-Gerasimeenternko, and to investigate its dusty environment six years after Rosetta with complementary methods is unique and strongly enhances and supports the scientific exploration of this target and the entire Rosetta mission. Launch opportunities are in 2020 with a backup window starting early 2026. The comet encounter occurs in September 2021 and the reentry takes place in early 2024. An encounter speed of 6 km/s ensures comparable results to the Stardust mission.}, 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{HenzeAumerGrabneretal.2011, author = {Henze, Andrea and Aumer, Franziska and Grabner, Arthur and Raila, Jens and Schweigert, Florian J.}, title = {Genetic differences in the serum proteome of horses, donkeys and mules are detectable by protein profiling}, series = {The British journal of nutrition : an international journal devoted to the science of human and animal nutrition}, volume = {106}, journal = {The British journal of nutrition : an international journal devoted to the science of human and animal nutrition}, publisher = {Cambridge Univ. Press}, address = {Cambridge}, issn = {0007-1145}, doi = {10.1017/S0007114511000845}, pages = {S170 -- S173}, year = {2011}, abstract = {Although horses and donkeys belong to the same genus, their genetic characteristics probably result in specific proteomes and post-translational modifications (PTM) of proteins. Since PTM can alter protein properties, specific PTM may contribute to species-specific characteristics. Therefore, the aim of the present study was to analyse differences in serum protein profiles of horses and donkeys as well as mules, which combine the genetic backgrounds of both species. Additionally, changes in PTM of the protein transthyretin (TTR) were analysed. Serum protein profiles of each species (five animals per species) were determined using strong anion exchanger ProteinChips (R) (Bio-Rad, Munich, Germany) in combination with surface-enhanced laser desorption ionisation-time of flight MS. The PTM of TTR were analysed subsequently by immunoprecipitation in combination with matrix-assisted laser desorption ionisation-time of flight MS. Protein profiling revealed species-specific differences in the proteome, with some protein peaks present in all three species as well as protein peaks that were unique for donkeys and mules, horses and mules or for horses alone. The molecular weight of TTR of horses and donkeys differed by 30Da, and both species revealed several modified forms of TTR besides the native form. The mass spectra of mules represented a merging of TTR spectra of horses and donkeys. In summary, the present study indicated that there are substantial differences in the proteome of horses and donkeys. Additionally, the results probably indicate that the proteome of mules reveal a higher similarity to donkeys than to horses.}, language = {en} }