[PDF] Identification Of Protein Ligand Binding Sites By Top Down Mass Spectrometry eBook

Author : Piriya Wongkongkathep
Publisher :
Page : 170 pages
File Size : 27,47 MB
Release : 2015
Category :
ISBN :

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Mass spectrometry (MS) has made significant contributions to protein and proteomics analysis during the past decades from its advantages of speed, sensitivity, specificity, and low sample consumption. While the proteomics field grows rapidly to identify thousands of proteins in a single analysis, "native" mass spectrometry, exploiting the unique features of electrospray ionization (ESI) for delivering large macromolecules to the mass spectrometer, has provided many potential exciting capabilities and applications to structural biology and biochemistry. It can analyze proteins in their native states, i.e., structures present in their native configurations from physiological pH solutions, with minimal sample preparation. In this thesis, I describe the application of native ESI combined with top-down MS using electron capture dissociation (ECD) and ion mobility (IM) to characterize the molecular features of protein-ligand complexes. Binding and structural information can be comprehensively obtained from this experimental platform. Native ESI-MS alone provides molecular mass, stoichiometry, and binding affinity, all from a single analysis. We demonstrate that top-down MS, the fragmentation of intact proteins and protein complexes using MS, offers a powerful capability to elucidate the location of ligand binding on a protein's structure and for probing the surface topology of proteins. Ion mobility mass spectrometry, a recently developed technique that yields information on the structural conformation of molecules, was used to reveal structural changes of proteins upon ligand binding. My thesis focuses on several proteins, including -synuclein (AS), which is a small protein related to Parkinson's disease. AS is natively unfolded at physiological pH, which makes it difficult to study by standard methods such as X-ray crystallography or NMR. Using our mass spectrometry techniques, transition metal binding (copper, cobalt, and manganese) to AS that is associated with accelerating fibril formation was monitored. The binding of a small molecule amyloid inhibitor called molecular tweezer (MT or CLR01) on two model proteins important in neurodegenerative diseases, AS and superoxide dismutase (SOD1), was studied. Tandem mass spectrometry (MS/MS) techniques such as collisionally activated dissociation (CAD) along with ECD were used to characterize the sites of binding of small molecule ligands to proteins. Ion mobility mass spectrometry was implemented to reveal the conformational changes of AS upon metal binding. It was demonstrated that copper can induce the AS protein to collapse into a more compact state, which may provide a hint of the mechanisms behind amyloid fibrillation. Additionally, two new methods to extend the application of top-down MS for protein structure characterization were developed. First, the same molecular tweezer molecule, which has a specificity to bind lysine residues, was used to probe surface residues of proteins. The lysines found to bind to the molecular tweezers identified by top-down MS correlates well with solvent accessibility values, suggesting that the MT compound can be applied as a molecular probe to pinpoint surface active lysine residues. Lastly, supplemental activation methods by ultraviolet and infrared laser irradiation prior to ECD was applied to assist disulfide bond cleavage of complex multiple intermolecular and intramolecular disulfide bond-containing proteins. Backbone bond cleavage from top-down MS was significantly increased when the disulfide bonds were cleaved, allowing more sequence information to be obtained. The new methods described in this thesis extend the applicability of mass spectrometry to provide a more complete picture of a protein's structure.

Author : Michael Nshanian
Publisher :
Page : 175 pages
File Size : 46,79 MB
Release : 2018
Category :
ISBN :

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The advent of top-down protein mass spectrometry (MS), or direct analysis of intact proteins forgoing proteolysis, has transformed the field of protein mass spectrometry, ushering in a new era of protein identification and characterization together with a new set of challenges. The analysis of intact proteins and their direct fragmentation in tandem (MS/MS) mode helps overcome the "inference" problem associated with peptide-based bottom-up proteomics; that is, correctly assigning given peptide fragments and their modifications to the intact protein from which they originated. Despite its many advantages, however, the top-down approach requires extensive sample fractionation and suffers from low sensitivity but much progress has been made. From recently-developed cross-linked polyacrylamide gels, from which intact proteins can be more easily recovered, to the discovery of reagents that enhance protein charging in electrospray ionization (ESI), there have been considerable gains in detection and sensitivity, offering the potential for a more complete and accurate characterization of a "proteoform": the full complement of the combinatorial possibilities that could arise from a given gene product. Top-down MS also includes the study of proteins in their native or native-like states. This is especially important in characterizing disease-related proteins, particularly in the context of protein aggregation. Native MS, using electron-capture dissociation (ECD) and ion mobility spectrometry (IMS), enables the study of protein-inhibitor complexes in the gas phase, offering structural insight into stoichiometry, site of inhibitor binding and mechanism of inhibition. In addition, intact analysis and electron-based fragmentation enable the detection of thermally-labile post-translational modifications like phosphorylation, known to play key regulatory roles in shifting proteins towards cytotoxic states. Top-down method developments in protein recovery, separation and supercharging have led to improvements in detection and sensitivity, while top-down MS applications to structural characterization of disease-related proteins have shed more light on the mechanisms of cytotoxic aggregation, offering greater promise of therapeutic development.

Author : Irena Roterman-Konieczna
Publisher : Springer Science & Business Media
Page : 173 pages
File Size : 11,72 MB
Release : 2012-10-19
Category : Medical
ISBN : 9400752849

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This volume presents a review of the latest numerical techniques used to identify ligand binding and protein complexation sites. It should be noted that there are many other theoretical studies devoted to predicting the activity of specific proteins and that useful protein data can be found in numerous databases. The aim of advanced computational techniques is to identify the active sites in specific proteins and moreover to suggest a generalized mechanism by which such protein-ligand (or protein-protein) interactions can be effected. Developing such tools is not an easy task – it requires extensive expertise in the area of molecular biology as well as a firm grasp of numerical modeling methods. Thus, it is often viewed as a prime candidate for interdisciplinary research.

Author : Colin Kleanthous
Publisher : Frontiers in Molecular Biology
Page : 370 pages
File Size : 48,97 MB
Release : 2000
Category : Carrier proteins
ISBN : 9780199637607

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The purpose of Protein-Protein Recognition is to bring together concepts and systems pertaining to protein-protein interactions in a single unifying volume. In the light of the information from the genome sequencing projects and the increase in structural information it is an opportune time totry to make generalizations about how and why proteins form complexes with each other. The emphasis of the book is on heteromeric complexes (complexes in which each of the components can exist in an unbound state) and will use well-studied model systems to explain the processes of formingcomplexes. After an introductory section on the kinetics, thermodynamics, analysis, and classification of protein-protein interactions, weak, intermediate, and high affinity complexes are dealt with in turn. Weak affinity complexes are represented by electron transfer proteins and integrincomplexes. Anti-lysozyme antibodies, the MHC proteins and their interactions with T-cell receptors, and the protein interactions of eukaryotic signal transduction are the systems used to explain complexes with intermediate affinities. Finally, tight binding complexes are represented by theinteraction of protein inhibitors with serine proteases and by nuclease inhibitor complexes. Throughout the chapters common themes are the technologies which have had the greatest impact, how specificity is determined, how complexes are stabilized, and medical and industrial applications.

Author : Richard B. Cole
Publisher : John Wiley & Sons
Page : 900 pages
File Size : 20,56 MB
Release : 2011-09-26
Category : Science
ISBN : 1118211553

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Discover how advances in mass spectrometry are fueling new discoveries across a broad range of research areas Electrospray and MALDI Mass Spectrometry brings both veteran practitioners and beginning scientists up to date with the most recent trends and findings in electrospray ionization and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. In particular, this Second Edition highlights how advances in electrospray and MALDI mass spectrometry are supporting important discoveries in new and emerging fields such as proteomics and metabolomics as well as in traditional areas of chemistry and physics research. Electrospray AND MALDI Mass Spectrometry, SECOND EDITION is divided into five parts: Part A, Fundamentals of ES, explains the fundamental phenomena underlying the electrospray process, including selectivity in ionization and inherent electrochemistry, and concludes with a chapter offering a comparative inventory of source hardware Part B, Fundamentals of MALDI, confronts ionization mechanisms, instrument development, and matrix selection, and includes a final chapter that explores the special application of MALDI to obtain two-dimensional images of spatial distributions of compounds on surfaces Part C, ES and MALDI Coupling to Mass Spectrometry Instrumentation, examines the coupling of these ionization techniques to various mass analyzers, including quadrupole ion trap, time-of-flight, Fourier transform ion cyclotron resonance, and ion mobility mass spectrometers Part D, Practical Aspects of ES and MALDI, investigates analytical issues including quantification, charge-state distributions, noncovalent interactions in solution that are preserved as gas-phase ions, and various means of ion excitation in preparation for tandem mass spectrometry, and offers a guide to the interpretation of even-electron mass spectra Part E, Biological Applications of ES and MALDI, examines the role of mass spectrometry in such areas as peptide and protein characterization, carbohydrate analysis, lipid analysis, and drug discovery Written by a team of leading experts, the book not only provides a critical review of the literature, but also presents key concepts in tutorial fashion to help readers take full advantage of the latest technological breakthroughs and applications. As a result, Electrospray and MALDI Mass Spectrometry will help researchers fully leverage the power of electrospray and MALDI mass spectrometry. The judicious compartmentalization of chapters, and the pedagogic presentation style throughout, render the book highly suitable for use as a text for graduate-level courses in advanced mass spectrometry.

Author : Raj Bawa
Publisher : CRC Press
Page : 1426 pages
File Size : 14,84 MB
Release : 2023-10-18
Category : Medical
ISBN : 1000602044

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Medical care is the most critical issue of our time and will be so for the foreseeable future. In this regard, the pace and sophistication of advances in medicine in the past two decades have been truly breathtaking. This has necessitated a growing need for comprehensive reference resources that highlight current issues in specific sectors of medicine. Keeping this in mind, each volume in the Current Issues in Medicine series is a stand‐alone text that provides a broad survey of various important topics in a focused area of medicine—all accomplished in a user-friendly yet interconnected format. This volume addresses advances in medical imaging, detection, and diagnostic technologies. Technological innovations in these sectors of medicine continue to provide for safer, more accurate, and faster diagnosis for patients. This translates into superior prognosis and better patient compliance, while reducing morbidity and mortality. Hence, it is imperative that practitioners stay current with these latest advances to provide the best care for nursing and clinical practices. While recognizing how expansive and multifaceted these areas of medicine are, Advances in Medical Imaging, Detection, and Diagnosis addresses crucial recent progress, integrating the knowledge and experience of experts from academia and the clinic. The multidisciplinary approach reflected makes this volume a valuable reference resource for medical practitioners, medical students, nurses, fellows, residents, undergraduate and graduate students, educators, venture capitalists, policymakers, and biomedical researchers. A wide audience will benefit from having this volume on their bookshelf: health care systems, the pharmaceutical industry, academia, and government.

Author : Alberto Podjarny
Publisher : Royal Society of Chemistry
Page : 373 pages
File Size : 47,19 MB
Release : 2011
Category : Science
ISBN : 1849730091

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This book provides a complete overview of current techniques to identify ligands, characterize their binding sites, and understand binding mechanisms. Suitable for biomolecular scientists at graduate or post-doctoral level in academia and industry.

Author : Chi Ho Ngan
Publisher :
Page : 352 pages
File Size : 46,92 MB
Release : 2012
Category :
ISBN :

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Abstract: Ligand binding sites in proteins generally include "hot spots" that contribute a large fraction of the binding free energy and, therefore, are of prime interest in drug design. To find hot spots on the protein surface, a protein can be screened against libraries of small organic molecules to identify interaction sites using nuclear magnetic resonance (NMR) spectroscopy or the X-ray crystallographic technique Multiple Solvent Crystal Structures (MSCS). Small organic molecules can bind at several locations on the surface of a protein, but many different molecules congregate only in "consensus sites" identifying the hot spots. The mapping algorithm FTMAP is a computational analogue of experimental fragment screening methods. The principles of computational mapping were used for the development and testing of the binding site identification algorithm FTSITE, implemented as a web-based server. Finding ligand binding sites in silico is a classical challenge, and the success rate of identifying the ligand binding site as the first predicted site has increased to 83% during the last decade. FTSITE, based on biophysical modeling of protein-ligand interactions, increased the success rate to 94% on the same established test sets. Critical to the success of FTSITE is the use of multiple small molecules as probes; screening by X-ray crystallography and NMR spectroscopy had demonstrated a tendency of ligand binding sites to bind small organic compounds ranging in shapes, sizes, and polarities. Further, FTSITE does not use surrogate measures of ligand binding propensity such as site geometries and dimensions. It was shown that FTSITE can also successfully identify allosteric ligand binding sites that can serve as candidates for drug design. Furthermore, the hot spot information provided by FTMAP was shown to guide the development of core fragments, found by experimental fragment screening, into optimal ligands for a number of drug target proteins. Computational mapping can also be used for fragment-based drug design by finding fragments with preference for some regions of the binding site. To facilitate this analysis, a server enabling the fast generation of force field parameters for user-specified small molecules or fragments was developed.