Proteome analysis of Helicobacter pylori: Major proteins of type strain NCTC 11637

Proteome analysis involves the simultaneous resolution and display of prote ins produced by an organism, followed by the quantitation, characterisation and identification of these proteins. As part of an ongoing study mapping and comparing the proteins expressed by various strains of the pathogenic b acterium Helicobacter pylori, we have resolved and identified 93 of the mos t abundant proteins expressed by type reference strain NCTC 11637. Proteins were separated by two-dimensional gel electrophoresis and stained with Coo massie G250. Intensely-stained spots were excised and digested with trypsin , and the resulting peptides were characterised by mass spectrometry. Prote ins were then identified by correlating actual peptide profiles with theore tical profiles generated from published nucleotide sequences. Ninety-three of the most intensely-stained protein spots were identified as the products of 35 genes, giving a ratio of 2.7 protein gene-products per gene. The pro ducts of the tsaA, pfr, ureA and ureB genes were amongst several proteins p resent in multiple isoforms. Peptide mass fingerprinting data were used to identify probable post-translational protein modifications. These results s uggest that H. pylori proteins are subject to a high degree of post-transla tional modification. Comparative proteomics of H. pylori strains should gre atly assist in investigating the pathogenic properties of this bacterium.