IDENTIFICATION AND CHARACTERIZATION OF AN OPERON OF HELICOBACTER-PYLORI THAT IS INVOLVED IN MOTILITY AND STRESS-ADAPTATION

We identified a novel stress-responsive operon (sro) of Helicobacter p ylori that contains seven genes which are likely to be involved in cel lular functions as diverse as chemotaxis, heat shock response, ion tra nsport, and posttranslational protein modification, The products of th ree of these genes show amino acid homologies to known proteins, such as the flagellar motor switch protein CheY, a class of heat shock prot eins, and the ribosomal protein L11 methyltransferase, and to a phosph atidyltransferase. In addition to containing an open reading frame of unknown function, the product of which is predicted to be membrane ass ociated, the sro locus contains three open reading frames that have pr eviously been described as constituting two separate loci, the ftsH ge ne and the copAP operon of H. pylori, Knockout mutants showed that Che Y is essential for bacterial motility and that CopA, but not CopP, rel ieves copper toxicity, Transcriptional analyses indicated that this lo cus is regulated by a single promoter and that a positive effect on tr anscription is exerted by the addition of copper to the medium and by temperature upshift from 37 to 45 degrees C. The possible role of this locus in H. pylori virulence is discussed.