3gz2
Crystal structure of IpgC in complex with an IpaB peptide
Structural highlights
FunctionIPGC_SHIFL Assists the correct folding of nascent IpaB. Once it is bound to IpaB, it binds to IpaC and impedes their premature association that would lead to their degradation in the absence of IpcG. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedType 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. References
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