Helicobacter pylori Outer Membrane Proteins
Yoshio Yamaoka and Richard A. Alm
from: Helicobacter pylori: Molecular Genetics and Cellular Biology (Edited by: Yoshio Yamaoka). Caister Academic Press, U.K. (2008)
Analysis of the three completed Helicobacter pylori genomes has confirmed the presence of five major outer membrane proteins (OMPs) families. However, there appears to be a trend within the protein families as to which two of the three orthologs are more closely related. H. pylori 26695 and HPAG1 proteins are the most closely related more often as H. pylori J99 and HPAG1 or H. pylori J99 and 26695. Whether this is because both HPAG1 and 26695 were isolated from gastritis patients and J99 from a duodenal ulcer patient is an intriguing, but untested possibility. It has been demonstrated that several OMPs in the largest family act as adhesions, and these include BabA, SabA, OipA, AlpAB and HopZ. This unusual set of specialized OMPs may be a reflection of the adaptation of H. pylori to the unique gastric environment where it is found. Many of these genes undergo phase variation such that not all strains will produce functional proteins, and the stability of expression with passage varied with OipA > BabA > BabB > SabA. In this chapter, as well as describing the general features of the H. pylori OMP families, we describe the well characterized OMPs (BabA, SabA and OipA) in detail. Each OMP appears to have specific functions, and further studies will be necessary for investigating the detailed analyses of these OMPs as well as many unstudied OMPs read more ...