Technologies for bacterial surface proteomics

Proteins from bacterial membranes are notoriously difficult to analyze using the traditional technologies encompassed under the term ‘proteomics’. This is because of several factors, including the comparatively low abundance of most membrane proteins within a complex mixture containing cytoplasmic metabolic enzymes, the poor solubility of membrane components such as phospholipids, lipopolysaccharides and peptidoglycans, and the inherent hydrophobicity of many integral membrane proteins that contain up to 15 transmembrane-spanning regions. Recent advances in gel-based and chromatographic separations, coupled with protein and peptide labelling and the exquisite sensitivity of mass spectrometry, are finally beginning to overcome these problems. New technologies in membrane proteomics enable comparative analysis of these recalcitrant proteins from bacteria under a variety of biological conditions.