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Martin Lorenz Eisinger, Laiyin Nie, Aline Ricarda Dörrbaum, Julian David Langer, Hartmut Michel
Multidrug resistance (MDR) in bacterial pathogens has become a severe threat to public health. Membrane transporters of the multidrug and toxic compound extrusion (MATE) family contribute critically to MDR, making them promising drug targets. Despite recent advances, structures in different conformations and the mechanistic details of their antiport cycle are still elusive. Here we studied NorM_PS, a representative MATE transporter from Pseudomonas stutzeri, using biochemical assays in combination with hydrogen/deuterium exchange-mass spectrometry (HDX-MS)...
March 16, 2018: Journal of Molecular Biology
Laura J Byrnes, Yingrong Xu, Xiayang Qiu, Justin D Hall, Graham M West
Cystic Fibrosis (CF) is caused by mutations in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR). Mutations associated with CF cause loss-of-function in CFTR leading to salt imbalance in epithelial tissues. Kalydeco (also called VX-770 or ivacaftor) was approved for CF treatment in 2012 but little is known regarding the compound's interactions with CFTR including the site of binding or mechanisms of action. In this study we use hydrogen/deuterium exchange (HDX) coupled with mass spectrometry to assess the conformational dynamics of a thermostabilized form of CFTR in apo and ligand-bound states...
March 16, 2018: Scientific Reports
Kinga Nyíri, Haydyn D T Mertens, Borbála Tihanyi, Gergely N Nagy, Bianka Kőhegyi, Judit Matejka, Matthew J Harris, Judit E Szabó, Veronika Papp-Kádár, Veronika Németh-Pongrácz, Olivér Ozohanics, Károly Vékey, Dmitri I Svergun, Antoni J Borysik, Beáta G Vértessy
Human deoxyuridine 5'-triphosphate nucleotidohydrolase (dUTPase), essential for DNA integrity, acts as a survival factor for tumor cells and is a target for cancer chemotherapy. Here we report that the Staphylococcal repressor protein StlSaPIBov1 (Stl) forms strong complex with human dUTPase. Functional analysis reveals that this interaction results in significant reduction of both dUTPase enzymatic activity and DNA binding capability of Stl. We conducted structural studies to understand the mechanism of this mutual inhibition...
March 12, 2018: Scientific Reports
Yoshitomo Hamuro, Sook Yen E
The technological goal of hydrogen/deuterium exchange-mass spectrometry (HDX-MS) is to determine backbone amide hydrogen exchange rates. The most critical challenge to achieve this goal is obtaining the deuterium incorporation in single-amide resolution, and gas-phase fragmentation may provide a universal solution. The gas-phase fragmentation may generate the daughter ions which differ by a single amino acid and the difference in deuterium incorporations in the two analogous ions can yield the deuterium incorporation at the sub-localized site...
March 2, 2018: Journal of the American Society for Mass Spectrometry
Ravi G Kurumbail, Graham M West, Venkatasubramanian Dharmarajan, Kris A Borzilleri, Jane M Withka, Jessica Ward, Allan R Reyes, Francis Rajamohan, Patrick R Griffin, Matthew F Calabrese
Protein-ligand interactions can be evaluated by a number of different biophysical methods. Here we describe some of the experimental methods that we have used to generate AMPK protein reagents and characterize its interactions with direct synthetic activators. Recombinant heterotrimeric AMPK complexes were generated using standard molecular biology methods by expression either in insect cells via infection with three different viruses or more routinely in Escherichia coli with a tricistronic expression vector...
2018: Methods in Molecular Biology
Tom D Bunney, Alison J Inglis, Domenico Sanfelice, Brendan Farrell, Christopher J Kerr, Gary S Thompson, Glenn R Masson, Nethaji Thiyagarajan, Dmitri I Svergun, Roger L Williams, Alexander L Breeze, Matilda Katan
Receptor tyrosine kinase FGFR3 is involved in many signaling networks and is frequently mutated in developmental disorders and cancer. The Hsp90/Cdc37 chaperone system is essential for function of normal and neoplastic cells. Here we uncover the mechanistic inter-relationships between these proteins by combining approaches including NMR, HDX-MS, and SAXS. We show that several disease-linked mutations convert FGFR3 to a stronger client, where the determinant underpinning client strength involves an allosteric network through the N-lobe and at the lobe interface...
February 16, 2018: Structure
Gavin R Owen, Doris Le, Stoyan Stoychev, Nichole M Cerutti, Maria Papathanasopoulos
CD4, a membrane glycoprotein expressed by specific leukocytes, plays a vital role in the human immune response and acts as a primary receptor for HIV entry. Of its four ecto-domains (D1-D4), D1, D2, and D4 each contain a distinctive disulfide bond. Whereas the disulfides of D1 and D4 are more traditional in nature, providing structural functions, that of D2 is referred to as an "allosteric" disulfide due to its high dihedral strain energy and relative ease of reduction that is thought to regulate CD4 structure and function by shuffling its redox state...
February 19, 2018: Biochemical and Biophysical Research Communications
Vincent S Shaw, Hossein Mohammadiarani, Harish Vashisth, Richard R Neubig
Small-molecule inhibitor selectivity may be influenced by variation in dynamics among members of a protein family. Regulator of G-protein Signaling (RGS) proteins are a family that plays a key role in G-Protein Coupled Receptor (GPCR) signaling by binding to active Gα subunits and accelerating GTP hydrolysis, thereby terminating activity. Thiadiazolidinones (TDZDs) inhibit the RGS-Gα interaction by covalent modification of cysteine residues in RGS proteins. Some differences in specificity may be explained by differences in the complement of cysteines among RGS proteins...
February 20, 2018: Journal of the American Chemical Society
Yirui Guo, Anthony T Iavarone, Matthew M Cooper, Michael A Marletta
Heme-nitric oxide/oxygen binding (H-NOX) proteins are a group of hemoproteins that bind diatomic gas ligands such as nitric oxide (NO) and oxygen (O2 ). H-NOX proteins typically regulate histidine kinases (HK) located within the same operon. It has been reported that NO-bound H-NOXs inhibit cognate histidine kinase autophosphorylation in bacterial H-NOX/HK complexes, however, a detailed mechanism of NO-mediated regulation of the H-NOX/HK activity remains unknown. In this study, the binding interface of Vibrio cholerae (Vc) H-NOX/HK complex was characterized by hydrogen/deuterium exchange mass spectrometry (HDX-MS) and further validated by mutagenesis, leading to a new model for NO-dependent kinase inhibition...
February 19, 2018: Biochemistry
Jiantong Du, Yaqian Huang, Kun Li, Xiaoqi Yu, Hongfang Jin, Liu Yang
Endogenous sulfur dioxide (SO2) was found to be generated from the enzymatic reaction catalysed by aspartate transference 1 (AAT1) in the mammals and play importantly biological effects. In the present study, we explored the existence of endogenous SO2 pathway in mouse retinal tissues and 661w photoreceptor cell and investigated its possible pathophysiological role in the hydrogen peroxide (H2O2)-induced mouse photoreceptor cell apoptosis. The data showed that endogenous SO2 pathway including AAT1 expression and SO2 content was found to be presented in mouse photoreceptor cells...
February 2, 2018: Biochemical and Biophysical Research Communications
Nicholas I Brodie, Romain Huguet, Terry Zhang, Rosa Viner, Vlad Zabrouskov, Jingxi Pan, Evgeniy V Petrotchenko, Christoph H Borchers
Top-down hydrogen-deuterium exchange (HDX) analysis using electron capture or transfer dissociation Fourier transform mass spectrometry is a powerful method for the analysis of secondary structure of proteins in solution. The resolution of the method is a function of the extensive fragmentation of backbone bonds in the proteins. While fragmentation is usually extensive near the N- and C-termini, electron capture (ECD) or electron transfer dissociation (ETD) fragmentation methods sometimes lack good coverage of certain regions of the protein - most often in the middle of the sequence...
January 16, 2018: Analytical Chemistry
Joey P Ting, Frances Tung, Stephen Antonysamy, Stephen Wasserman, Spencer B Jones, Feiyu F Zhang, Alfonso Espada, Howard Broughton, Michael J Chalmers, Michael E Woodman, Holly A Bina, Jeffrey A Dodge, Jordi Benach, Aiping Zhang, Christopher Groshong, Danalyn Manglicmot, Marijane Russell, Sepideh Afshar
To date, IL-17A antibodies remain the only therapeutic approach to correct the abnormal activation of the IL-17A/IL-17R signaling complex. Why is it that despite the remarkable success of IL-17 antibodies, there is no small molecule antagonist of IL-17A in the clinic? Here we offer a unique approach to address this question. In order to understand the interaction of IL-17A with its receptor, we combined peptide discovery using phage display with HDX, crystallography, and functional assays to map and characterize hot regions that contribute to most of the energetics of the IL-17A/IL-17R interaction...
2018: PloS One
B Setner, M Wierzbicka, L Jerzykiewicz, M Lisowski, Z Szewczuk
Recently, we developed a novel non-fragmenting quaternary ammonium ionization tag for the mass spectrometric sensitive sequencing of peptides, based on the N-spiro proline residue (5-azoniaspiro[4.4.]nonyl-carbonyl). Herein, we present an unexpected racemization and the hydrogen-deuterium exchange (HDX) at the α-C atom of the proline derivative under basic aqueous conditions (1% water solution of triethylamine). The deuterium atom, substituted for the α-C atom, does not undergo back-exchange under acidic aqueous conditions which makes the deuterated isotopologue a promising stabile isotope-coded internal standard for quantitative analysis by mass spectrometry...
January 12, 2018: Organic & Biomolecular Chemistry
Yoshitomo Hamuro, Stephen J Coales
The practice of HDX-MS remains somewhat difficult, not only for newcomers but also for veterans, despite its increasing popularity. While a typical HDX-MS project starts with a feasibility stage where the experimental conditions are optimized and the peptide map is generated prior to the HDX study stage, the literature usually reports only the HDX study stage. In this protocol, we describe a few considerations for the initial feasibility stage, more specifically, how to optimize quench conditions, how to tackle the carryover issue, and how to apply the pepsin specificity rule...
January 3, 2018: Journal of the American Society for Mass Spectrometry
Darragh P O'Brien, Dominique Durand, Alexis Voegele, Véronique Hourdel, Marilyne Davi, Julia Chamot-Rooke, Patrice Vachette, Sébastien Brier, Daniel Ladant, Alexandre Chenal
Once translocated into the cytosol of target cells, the catalytic domain (AC) of the adenylate cyclase toxin (CyaA), a major virulence factor of Bordetella pertussis, is potently activated by binding calmodulin (CaM) to produce supraphysiological levels of cAMP, inducing cell death. Using a combination of small-angle X-ray scattering (SAXS), hydrogen/deuterium exchange mass spectrometry (HDX-MS), and synchrotron radiation circular dichroism (SR-CD), we show that, in the absence of CaM, AC exhibits significant structural disorder, and a 75-residue-long stretch within AC undergoes a disorder-to-order transition upon CaM binding...
December 29, 2017: PLoS Biology
Camille Martin, Claire Kizlik-Masson, André Pèlegrin, Hervé Watier, Marie-Claude Viaud-Massuard, Nicolas Joubert
The annual "Antibody Industrial Symposium", co organized by LabEx MAbImprove, MabDesign and Polepharma, was held in Tours, France on June 27-28, 2017. The focus was on antibody-drug-conjugates (ADCs), new entities which realize the hope of Paul Ehrlich's magic bullet. ADCs result from the bioconjugation of a highly cytotoxic drug to a selective monoclonal antibody, which acts as a vector. Building on knowledge gained during the development of three approved ADCs, brentuximab vedotin (Adcetris®), ado trastuzumab emtansine (Kadcyla®) and inotuzumab ozogamicin (Besponsa®), and the many ADCs in development, this meeting addressed strategies and the latest innovations in the field from fundamental research to manufacturing...
December 14, 2017: MAbs
Xiaofeng Li, Yeqing Tao, James W Murphy, Alexander N Scherer, TuKiet T Lam, Alan G Marshall, Anthony J Koleske, Titus J Boggon
The multi-domain protein, cortactin, contains a 37-residue repeating motif that binds to actin filaments. This cortactin repeat region comprises 6½ similar copies of the motif and binds actin filaments. To better understand this region of cortactin, and its fold, we conducted extensive biophysical analysis. Size exclusion chromatography with multi-angle light scattering (SEC-MALS) reveals that neither constructs of the cortactin repeats alone or together with the adjacent helical region homo-oligomerize. Using circular dichroism (CD) we find that in solution the cortactin repeats resemble a coil-like intrinsically disordered protein...
December 1, 2017: Scientific Reports
Altijana Hromić-Jahjefendić, Nina Jajčanin Jozić, Saša Kazazić, Marina Grabar Branilović, Zrinka Karačić, Jörg H Schrittwieser, Krishna Mohan Padmanabha Das, Marko Tomin, Monika Oberer, Karl Gruber, Marija Abramić, Sanja Tomić
Porphyromonas gingivalis, an asaccharolytic Gram-negative oral anaerobe, is a major pathogen associated with adult periodontitis, a chronic infective disease that a significant percentage of the human population suffers from. It preferentially utilizes dipeptides as its carbon source, suggesting the importance of dipeptidyl peptidase (DPP) types of enzyme for its growth. Until now DPP IV, DPP5, 7 and 11 have been extensively investigated. Here, we report the characterization of DPP III using molecular biology, biochemical, biophysical and computational chemistry methods...
2017: PloS One
Yicheng Long, Ben Bolanos, Lihu Gong, Wei Liu, Karen J Goodrich, Xin Yang, Siming Chen, Anne R Gooding, Karen A Maegley, Ketan S Gajiwala, Alexei Brooun, Thomas R Cech, Xin Liu
Polycomb repressive complex 2 (PRC2) is a key chromatin modifier responsible for methylation of lysine 27 in histone H3. PRC2 has been shown to interact with thousands of RNA species in vivo, but understanding the physiological function of RNA binding has been hampered by the lack of separation-of-function mutants. Here, we use comprehensive mutagenesis and hydrogen deuterium exchange mass spectrometry (HDX-MS) to identify critical residues for RNA interaction in PRC2 core complexes from Homo sapiens and Chaetomium thermophilum , for which crystal structures are known...
November 29, 2017: ELife
Peter Kochunov, Erin W Dickie, Joseph D Viviano, Jessica Turner, Peter B Kingsley, Neda Jahanshad, Paul M Thompson, Meghann C Ryan, Els Fieremans, Dmitry Novikov, Jelle Veraart, Elliot L Hong, Anil K Malhotra, Robert W Buchanan, Sofia Chavez, Aristotle N Voineskos
A novel mega-analytical approach that reduced methodological variance was evaluated using a multisite diffusion tensor imaging (DTI) fractional anisotropy (FA) data by comparing white matter integrity in people with schizophrenia to controls. Methodological variance was reduced through regression of variance captured from quality assurance (QA) and by using Marchenko-Pastur Principal Component Analysis (MP-PCA) denoising. N = 192 (119 patients/73 controls) data sets were collected at three sites equipped with 3T MRI systems: GE MR750, GE HDx, and Siemens Trio...
February 2018: Human Brain Mapping
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