1k3s
Type III Secretion Chaperone SigE
OverviewOverview
Several Gram-negative bacterial pathogens have evolved a type III secretion system to deliver virulence effector proteins directly into eukaryotic cells, a process essential for disease. This specialized secretion process requires customized chaperones specific for particular effector proteins. The crystal structures of the enterohemorrhagic Escherichia coli O157:H7 Tir-specific chaperone CesT and the Salmonella enterica SigD-specific chaperone SigE reveal a common overall fold and formation of homodimers. Site-directed mutagenesis suggests that variable, delocalized hydrophobic surfaces observed on the chaperone homodimers are responsible for specific binding to a particular effector protein. Isothermal titration calorimetry studies of Tir-CesT and enzymatic activity profiles of SigD-SigE indicate that the effector proteins are not globally unfolded in the presence of their cognate chaperones.
About this StructureAbout this Structure
1K3S is a Single protein structure of sequence from Salmonella enterica. Full crystallographic information is available from OCA.
ReferenceReference
Structural and biochemical characterization of the type III secretion chaperones CesT and SigE., Luo Y, Bertero MG, Frey EA, Pfuetzner RA, Wenk MR, Creagh L, Marcus SL, Lim D, Sicheri F, Kay C, Haynes C, Finlay BB, Strynadka NC, Nat Struct Biol. 2001 Dec;8(12):1031-6. PMID:11685226 Page seeded by OCA on Fri May 2 22:16:10 2008