Comparative proteome analysis of Helicobacter pylori

Helicobacter pylori, the causative agent of gastritis, ulcer and stomach ca rcinoma, infects approximately half of the worlds population. After sequenc ing the complete genome of two strains, 26695 and J99, we have approached t he demanding task of investigating the functional part of the genetic infor mation containing macromolecules, the proteome. The proteins of three strai ns of H. pylori, 26695 and J99, and a prominent strain used in animal model s SS1, were separated by a high-resolution two-dimensional electrophoresis technique with a resolution power of 5000 protein spots. Up to 1800 protein species were separated from H. pylori which had been cultivated for 5 days on agar plates. Using matrix-assisted laser desorption/ionization mass spe ctrometry (MALDI-MS) peptide mass fingerprinting we have identified 152 pro teins, including nine known virulence factors and 28 antigens. The three st rains investigated had only a few protein spots in common. We observe that proteins with an amino acid exchange resulting in a net change of only one charge are shifted in the two-dimensional electrophoresis (2-DE) pattern. T he expression of 27 predicted conserved hypothetical open reading frames (O RFs) and six unknown ORFs were confirmed. The growth conditions of the bact eria were shown to have an effect on the presence of certain proteins. A pr eliminary immunoblotting study using human sera revealed that this approach is ideal for identifying proteins of diagnostic or therapeutic value. H. p ylori 2-DE patterns with their identified protein species were added to the dynamic 2D-PAGE database (http://www.mpiib-berlin.mpg.de/2D-PAGE/). This b asic knowledge of the proteome in the public domain will be an effective in strument for the identification of new virulence or pathogenic factors, and antigens of potentially diagnostic or curative value against H. pylori.