Kinetic characterization of Salmonella FliK-FlhB interactions demonstrates complexity of the Type III secretion substrate-specificity switch.

ABSTRACT: The bacterial flagellum is a complex macromolecular machine consisting of more than 20 000 proteins, most of which must be exported from the cell via a dedicated Type III secretion apparatus. At a defined point in flagellar morphogenesis, hook completion is sensed and the apparatus switches substrate specificity type from rod and hook proteins to filament ones. How the switch works is a subject of intense interest. FliK and FlhB play central roles. In the present study, two optical biosensing methods were used to characterize FliK-FlhB interactions using wild-type and two variant FlhBs from mutants with severe flagellar structural defects. Binding was found to be complex with fast and slow association and dissociation components. Surprisingly, wild-type and variant FlhBs had similar kineti

SUBMITTER: Morris DP 

PROVIDER: S-EPMC2912450 | biostudies-literature | 2010 Aug

REPOSITORIES: biostudies-literature