3gz2

Publication Abstract from PubMed

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 an IpgC dimer bound to an IpaB fragment comprising both CBDs. Moreover, in the absence of this novel CBD the IpaB/IpgC complex aggregates. This dual-recognition of a domain in the protein by the chaperone in facilitating the correct chaperone-substrate organization describes a new function for the TTSS associated chaperone-substrate complexes.

Combination of two separate binding domains defines stoichiometry between type III secretion system chaperone IpgC and translocator protein IpaB.,Lokareddy RK, Lunelli M, Eilers B, Wolter V, Kolbe M J Biol Chem. 2010 Dec 17;285(51):39965-75. Epub 2010 Oct 11. PMID:20937829^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.