Combination of two separate binding domains defines stoichiometry between type III secretion system chaperone IpgC and translocator protein IpaB.

ABSTRACT: Type III secretion systems (TTSSs) utilized by enteropathogenic bacteria require the presence of small, acidic virulence-associated chaperones for effective host cell infection. We adopted a combination of biochemical and cellular techniques to define the chaperone binding domains (CBDs) in the translocators IpaB and IpaC associated with the chaperone IpgC from Shigella flexneri. We identified a novel CBD in IpaB and furthermore precisely mapped the boundaries of the CBDs in both translocator proteins. In IpaC a single binding domain associates with IpgC. In IpaB, we show that the binding of the newly characterized CBD is essential in maintaining the ternary arrangement of chaperone-translocator complex. This hitherto unknown function is reflected in the co-crystal structure as well, with

SUBMITTER: Lokareddy RK 

PROVIDER: S-EPMC3000978 | biostudies-literature | 2010 Dec

REPOSITORIES: biostudies-literature