Implementation of nano-liquid chromatography hyphenated to tandem mass spectrometry for protein identification in gel and non-gel based proteomics

This thesis is divided into three parts. Part I deals with the current status of large scale strategies for the analysis of proteins in biological systems. In Chapter I, genomics and the need to shift towards proteomic approaches are outlined. An overview of key technologies used in functional and structural proteomics is provided in Chapter II, whereas mass spectrometry and the strategies for profiling of proteins are discussed in detail in the final chapter of this part (Chapter III). Part II describes the analysis of cytosolic proteins by two-dimensional polyacrylamide gel electrophoresis and mass spectrometry. First, the techniques are highlighted that were used to identify gel separated proteins, i.e. the implementation of nano-liquid chromatography and mass spectrometry (Chapter IV). The next two chapters are applications of the developed methodology in two case studies: the protein composition of the dissimilatory iron-reducing bacterium Shewanella oneidensis MR-1 grown on ferric oxide (Chapter V) and the effect of a short-term heat shock on the plant barley (Chapter VI). Part III deals with the development of alternative strategies for the analysis of membrane proteins. A special electrophoretic technique, i.e. blue-native polyacrylamide gel electrophoresis, in combination with mass spectrometry, was used for profiling the different subunits of the oxidative phosphorylation system (Chapter VII), while multi-dimensional liquid chromatography coupled to MALDI tandem mass spectrometry was used for the profiling of the proteins present in the murine myelin sheath (Chapter VIII)

Myelin Proteomics: Molecular Anatomy of an Insulating Sheath

Fast-transmitting vertebrate axons are electrically insulated with multiple layers of nonconductive plasma membrane of glial cell origin, termed myelin. The myelin membrane is dominated by lipids, and its protein composition has historically been viewed to be of very low complexity. In this review, we discuss an updated reference compendium of 342 proteins associated with central nervous system myelin that represents a valuable resource for analyzing myelin biogenesis and white matter homeostasis. Cataloging the myelin proteome has been made possible by technical advances in the separation and mass spectrometric detection of proteins, also referred to as proteomics. This led to the identification of a large number of novel myelin-associated proteins, many of which represent low abundant components involved in catalytic activities, the cytoskeleton, vesicular trafficking, or cell adhesion. By mass spectrometry-based quantification, proteolipid protein and myelin basic protein constitute 17% and 8% of total myelin protein, respectively, suggesting that their abundance was previously overestimated. As the biochemical profile of myelin-associated proteins is highly reproducible, differential proteome analyses can be applied to material isolated from patients or animal models of myelin-related diseases such as multiple sclerosis and leukodystrophies