Novel Computational Methods for Mass Spectrometry Based Protein Identification

Novel Computational Methods for Mass Spectrometry Based Protein Identification PDF Author: Rachana Jain
Publisher:
ISBN:
Category :
Languages : en
Pages : 129

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Book Description
Mass spectrometry (MS) is used routinely to identify proteins in biological samples. Peptide Mass Fingerprinting (PMF) uses peptide masses and a pre-specified search database to identify proteins. It is often used as a complementary method along with Peptide Fragment Fingerprinting (PFF) or de-novo sequencing for increasing confidence and coverage of protein identification during mass spectrometric analysis. At the core of a PMF database search algorithm lies a similarity measure or quality statistics that is used to gauge the level to which an experimentally obtained peaklist agrees with a list of theoretically observable mass-to-charge ratios for a protein in a database. In this dissertation, we use publicly available gold standard data sets to show that the selection of search criteria such as mass tolerance and missed cleavages significantly affects the identification results. We propose, implement and evaluate a statistical (Kolmogorov-Smirnov-based) test which is computed for a large mass error threshold thus avoiding the choice of appropriate mass tolerance by the user. We use the mass tolerance identified by the Kolmogorov-Smirnov test for computing other quality measures. The results from our careful and extensive benchmarks suggest that the new method of computing the quality statistics without requiring the end-user to select a mass tolerance is competitive. We investigate the similarity measures in terms of their information content and conclude that the similarity measures are complementary and can be combined into a scoring function to possibly improve the over all accuracy of PMF based identification methods. We describe a new database search tool, PRIMAL, for protein identification using PMF. The novelty behind PRIMAL is two-fold. First, we comprehensively analyze methods for measuring the degree of similarity between experimental and theoretical peaklists. Second, we employ machine learning as a means of combining the individual similarity measures into a scoring function. Finally, we systematically test the efficacy of PRIMAL in identifying proteins using highly curated and publicly available data. Our results suggest that PRIMAL is competitive if not better than some of the tools extensively used by the mass spectrometry community. A web server with an implementation of the scoring function is available at http://bmi.cchmc.org/primal. We also note that the methodology is directly extensible to MS/MS based protein identification problem. We detail how to extend our approaches to the more complex MS/MS data.

Novel Computational Methods for Mass Spectrometry Based Protein Identification

Novel Computational Methods for Mass Spectrometry Based Protein Identification PDF Author: Rachana Jain
Publisher:
ISBN:
Category :
Languages : en
Pages : 129

Get Book Here

Book Description
Mass spectrometry (MS) is used routinely to identify proteins in biological samples. Peptide Mass Fingerprinting (PMF) uses peptide masses and a pre-specified search database to identify proteins. It is often used as a complementary method along with Peptide Fragment Fingerprinting (PFF) or de-novo sequencing for increasing confidence and coverage of protein identification during mass spectrometric analysis. At the core of a PMF database search algorithm lies a similarity measure or quality statistics that is used to gauge the level to which an experimentally obtained peaklist agrees with a list of theoretically observable mass-to-charge ratios for a protein in a database. In this dissertation, we use publicly available gold standard data sets to show that the selection of search criteria such as mass tolerance and missed cleavages significantly affects the identification results. We propose, implement and evaluate a statistical (Kolmogorov-Smirnov-based) test which is computed for a large mass error threshold thus avoiding the choice of appropriate mass tolerance by the user. We use the mass tolerance identified by the Kolmogorov-Smirnov test for computing other quality measures. The results from our careful and extensive benchmarks suggest that the new method of computing the quality statistics without requiring the end-user to select a mass tolerance is competitive. We investigate the similarity measures in terms of their information content and conclude that the similarity measures are complementary and can be combined into a scoring function to possibly improve the over all accuracy of PMF based identification methods. We describe a new database search tool, PRIMAL, for protein identification using PMF. The novelty behind PRIMAL is two-fold. First, we comprehensively analyze methods for measuring the degree of similarity between experimental and theoretical peaklists. Second, we employ machine learning as a means of combining the individual similarity measures into a scoring function. Finally, we systematically test the efficacy of PRIMAL in identifying proteins using highly curated and publicly available data. Our results suggest that PRIMAL is competitive if not better than some of the tools extensively used by the mass spectrometry community. A web server with an implementation of the scoring function is available at http://bmi.cchmc.org/primal. We also note that the methodology is directly extensible to MS/MS based protein identification problem. We detail how to extend our approaches to the more complex MS/MS data.

Computational Methods for Mass Spectrometry Proteomics

Computational Methods for Mass Spectrometry Proteomics PDF Author: Ingvar Eidhammer
Publisher: John Wiley & Sons
ISBN: 9780470724293
Category : Medical
Languages : en
Pages : 296

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Book Description
Proteomics is the study of the subsets of proteins present in different parts of an organism and how they change with time and varying conditions. Mass spectrometry is the leading technology used in proteomics, and the field relies heavily on bioinformatics to process and analyze the acquired data. Since recent years have seen tremendous developments in instrumentation and proteomics-related bioinformatics, there is clearly a need for a solid introduction to the crossroads where proteomics and bioinformatics meet. Computational Methods for Mass Spectrometry Proteomics describes the different instruments and methodologies used in proteomics in a unified manner. The authors put an emphasis on the computational methods for the different phases of a proteomics analysis, but the underlying principles in protein chemistry and instrument technology are also described. The book is illustrated by a number of figures and examples, and contains exercises for the reader. Written in an accessible yet rigorous style, it is a valuable reference for both informaticians and biologists. Computational Methods for Mass Spectrometry Proteomics is suited for advanced undergraduate and graduate students of bioinformatics and molecular biology with an interest in proteomics. It also provides a good introduction and reference source for researchers new to proteomics, and for people who come into more peripheral contact with the field.

Computational and Statistical Methods for Protein Quantification by Mass Spectrometry

Computational and Statistical Methods for Protein Quantification by Mass Spectrometry PDF Author: Ingvar Eidhammer
Publisher: John Wiley & Sons
ISBN: 111849377X
Category : Mathematics
Languages : en
Pages : 290

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Book Description
The definitive introduction to data analysis in quantitative proteomics This book provides all the necessary knowledge about mass spectrometry based proteomics methods and computational and statistical approaches to pursue the planning, design and analysis of quantitative proteomics experiments. The author’s carefully constructed approach allows readers to easily make the transition into the field of quantitative proteomics. Through detailed descriptions of wet-lab methods, computational approaches and statistical tools, this book covers the full scope of a quantitative experiment, allowing readers to acquire new knowledge as well as acting as a useful reference work for more advanced readers. Computational and Statistical Methods for Protein Quantification by Mass Spectrometry: Introduces the use of mass spectrometry in protein quantification and how the bioinformatics challenges in this field can be solved using statistical methods and various software programs. Is illustrated by a large number of figures and examples as well as numerous exercises. Provides both clear and rigorous descriptions of methods and approaches. Is thoroughly indexed and cross-referenced, combining the strengths of a text book with the utility of a reference work. Features detailed discussions of both wet-lab approaches and statistical and computational methods. With clear and thorough descriptions of the various methods and approaches, this book is accessible to biologists, informaticians, and statisticians alike and is aimed at readers across the academic spectrum, from advanced undergraduate students to post doctorates entering the field.

Computational Methods in Mass Spectrometry-Based Protein 3D Studies

Computational Methods in Mass Spectrometry-Based Protein 3D Studies PDF Author: Rosa M. Vitale
Publisher:
ISBN:
Category : Computers
Languages : en
Pages :

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Book Description
Computational Methods in Mass Spectrometry-Based Protein 3D Studies.

Novel Computational Techniques in Mass Spectrometry Based Proteomics

Novel Computational Techniques in Mass Spectrometry Based Proteomics PDF Author: Lukas Mueller
Publisher:
ISBN: 9783838332307
Category : Mass spectrometry
Languages : en
Pages : 144

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Book Description


Computational Methods for Protein-protein Complex Structure Prediction and Mass Spectrometry-based Identification

Computational Methods for Protein-protein Complex Structure Prediction and Mass Spectrometry-based Identification PDF Author: Weiwei Tong
Publisher:
ISBN:
Category :
Languages : en
Pages : 282

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Book Description
Abstract: Nearly all major processes in living cells are carried out by complex apparatus consisting of protein molecules. This thesis describes computational tools developed to help investigate two fundamental questions about proteins that underlie cell functions: how they interact with each other and form complex structures; and how they are expressed and modified in different cell states. In order to address the first question, several methods are developed to predict protein-protein complex structures. Protein interactions are energy driven processes. The prediction of protein complex structures is the search for the global minimum on the binding free-energy landscape. An approach is described that uses Van der Wools energy, desolvation energy and shape complementarity as the scoring functions and a five-dimensional fast Fourier transform algorithm to expedite the search. Two methods to screen and optimize the predicted protein complex structures are also introduced. They incorporate additional energy terms and clustering algorithms to provide more precise estimations of the binding free-energy. The same methods can also be used to predict hot spots, the mutations of which significantly alter the binding kinetics. To study the protein expression profiles, a two-step approach for protein identification using peptide mass fingerprinting data is developed. Peptide mass fingerprinting uses peptide masses determined by mass spectrometry to identify the peptides and subsequently, the proteins in the sample Peaks in the mass spectrum are associated with known peptide sequences in the database based on log-likelihood ratio test. A statistical algorithm is then used to identify proteins by comparing the probability of each protein's presence in the sample, given the peak assignments with the background probability. This method also discovers post-translational modifications in the identified proteins. The protein binding prediction program successfully predicts protein complex structures that closely resemble their native forms, as observed by x-ray crystallography or NMR. The refinements and hot spot predictions also give accurate and consistent results. The database search program that interprets mass spectrometry data is evaluated with artificial and experimental data. The program identifies proteins in the sample with high sensitivity and specificity. The results presented in this thesis demonstrate that computational methods help to better understand the structure and the composition of the protein machineries. All of the methods described herein have been implemented and made available for the research community over the Internet.

Mass Spectrometry Data Analysis in Proteomics

Mass Spectrometry Data Analysis in Proteomics PDF Author: Rune Matthiesen
Publisher:
ISBN: 9781627033923
Category : Mass spectrometry
Languages : en
Pages : 405

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Book Description
Since the publishing of the first edition, the methodologies and instrumentation involved in the field of mass spectrometry-based proteomics has improved considerably. Fully revised and expanded, Mass Spectrometry Data Analysis in Proteomics, Second Edition presents expert chapters on specific MS-based methods or data analysis strategies in proteomics. The volume covers data analysis topics relevant for quantitative proteomics, post translational modification, HX-MS, glycomics, and data exchange standards, among other topics. Written in the highly successful Methods in Molecular Biology series format, chapters include brief introductions to their respective subjects, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Updated and authoritative, Mass Spectrometry Data Analysis in Proteomics, Second Edition serves as a detailed guide for all researchers seeking to further our knowledge in the field of proteomics.

Novel Computational Techniques for Quantitative Mass Spectrometry Based Proteomics

Novel Computational Techniques for Quantitative Mass Spectrometry Based Proteomics PDF Author: Lukas Niklaus Müller
Publisher:
ISBN:
Category :
Languages : en
Pages : 145

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Book Description


Acceleration and Improvement of Protein Identification by Mass Spectrometry

Acceleration and Improvement of Protein Identification by Mass Spectrometry PDF Author: Willy Vincent Bienvenut
Publisher: Springer Science & Business Media
ISBN: 9781402033186
Category : Medical
Languages : en
Pages : 324

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Book Description
At present where protein identification and characterisation using mass spectrometry is a method of choice, this book is presenting a review of basic proteomic techniques. The second part of the book is related to the novel high throughput protein identification technique called the 'molecular scanner'. Several protein identification techniques are described, especially the peptide mass fingerprint with MALDI-MS based method. E.g. ionisation process, matrix available, signal reproducibility and suppression effect, as well as date treatment for protein identification using bioinformatics tools.

Introduction to Protein Mass Spectrometry

Introduction to Protein Mass Spectrometry PDF Author: Pradip K. Ghosh
Publisher: Academic Press
ISBN: 0128021128
Category : Science
Languages : en
Pages : 313

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Book Description
Introduction to Protein Mass Spectrometry provides a comprehensive overview of this increasingly important, yet complex, analytical technique. Unlike many other methods which automatically yield an absolutely unique protein name as output, protein mass spectrometry generally requires a deduction of protein identity from determination of peptide fragmentation products. This book enables readers to both understand, and appreciate, how determinations about protein identity from mass spectrometric data are made. Coverage begins with the technical basics, including preparations, instruments, and spectrometric analysis of peptides and proteins, before exploring applied use in biological applications, bioinformatics, database, and software resources. Citing the most recent and relevant work in the field of biological mass spectrometry, the book is written for researchers and scientists new to the field, but is also an ideal resource for those hoping to hone their analytical abilities. Offers introductory information for scientists and researchers new to the field, as well as advanced insight into the critical assessment of computer-analyzed mass spectrometric results and their current limitations Provides examples of commonly-used MS instruments from Bruker, Applied Biosystems, JEOL, Thermo Scientific/Thermo Fisher Scientific, IU, and Waters Includes biological applications and exploration of analytical tools and databases for bioinformatics