Interactions between C ring proteins and export apparatus components: a possible mechanism for facilitating type III protein export

摘要: The flagellar switch proteins of Salmonella, FliG, FliM and FliN, participate in the switching motor rotation, torque generation assembly/export. FliN has been implicated export process. To address this possibility, we constructed 10-amino-acid scanning deletions larger truncations over C-terminal domain FliN. Except for last deletion variant, all other variants were unable to complement a fliN null strain or restore proteins. Most showed strong negative dominance effects on wild-type cells. was found associate with FliH, component that regulates ATPase activity FliI. binding does not interfere FliN-FliH interaction. Furthermore, five-protein complex consisting His-tagged FliM, FliH FliI purified by nickel-affinity chromatography. FliJ, putative general chaperone, is bound even absence FliH. importance C ring as possible docking site substrates, chaperones through their efficient delivery membrane components apparatus discussed.