A FLAGELLAR-SPECIFIC ATPASE (FILI) IS NECESSARY FOR FLAGELLAR EXPORT IN HELICOBACTER-PYLORI

Although flagellar motility is essential for the colonisation of the s tomach by Helicobacter pylori, little is known about the regulation of flagellar biosynthesis in this organism. We have identified a gene in H. pylori, designated fliI, whose deduced amino acid sequence reveale d extensive homology with the FliI/LcrB/InvC family of proteins which energise the export of flagellar and other virulence factors in severa l bacterial species. An isogenic mutant of fliI was non-motile and syn thesised reduced amounts of flagellin and hook protein subunits. The m ajority (> 99%) of mutant cells were completely aflagellate. These res ults suggest that FliI is a novel ATPase involved in flagellar export in H. pylori.