Reductive evolution in outer membrane protein biogenesis has not compromised cell surface complexity in Helicobacter pylori

摘要

Abstract Helicobacter pylori is a gram-negative bacterial pathogen that chronically inhabits the human stomach. To survive and maintain advantage, it has evolved unique host?￠????pathogen interactions mediated by Helicobacter -specific proteins in the bacterial outer membrane. These outer membrane proteins (OMPs) are anchored to the cell surface via a C-terminal ???2-barrel domain, which requires their assembly by the ???2-barrel assembly machinery (BAM). Here we have assessed the complexity of the OMP C-terminal ???2-barrel domains employed by H. pylori, and characterized the H. pylori BAM complex. Around 50 Helicobacter -specific OMPs were assessed with predictive structural algorithms. The data suggest that H. pylori utilizes a unique ???2-barrel architecture that might constitute H. pylori -specific Type V secretions system. The structural and functional diversity in these proteins is encompassed by their extramembrane domains. Bioinformatic and biochemical characterization suggests that the low ???2-barrel-complexity requires only minimalist assembly machinery. The H. pylori proteins BamA and BamD associate to form a BAM complex, with features of BamA enabling an oligomerization that might represent a mechanism by which a minimalist BAM complex forms a larger, sophisticated machinery capable of servicing the outer membrane proteome of H. pylori .