Molecular evolution of the Helicobacter pylori vacuolating toxin gene vacA.

ABSTRACT: Helicobacter pylori is a genetically diverse organism that is adapted for colonization of the human stomach. All strains contain a gene encoding a secreted, pore-forming toxin known as VacA. Genetic variation at this locus could be under strong selection as H. pylori adapts to the host immune response, colonizes new human hosts, or inhabits different host environments. Here, we analyze the molecular evolution of VacA. Phylogenetic reconstructions indicate the subdivision of VacA sequences into three main groups with distinct geographic distributions. Divergence of the three groups is principally due to positively selected sequence changes in the p55 domain, a central region required for binding of the toxin to host cells. Divergent amino acids map to surface-exposed sites in the p55 crysta

SUBMITTER: Gangwer KA 

PROVIDER: S-EPMC2981223 | biostudies-literature | 2010 Dec

REPOSITORIES: biostudies-literature