Title of article :
Structures of the Shigella flexneri Type 3 Secretion System Protein MxiC Reveal Conformational Variability Amongst Homologues
Author/Authors :
Janet E. Deane، نويسنده , , Pietro Roversi، نويسنده , , CAROLE KING، نويسنده , , W. Steven Johnson، نويسنده , , Susan M. Lea، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2008
Pages :
8
From page :
985
To page :
992
Abstract :
Many Gram-negative pathogenic bacteria use a complex macromolecular machine, known as the type 3 secretion system (T3SS), to transfer virulence proteins into host cells. The T3SS is composed of a cytoplasmic bulb, a basal body spanning the inner and outer bacterial membranes, and an extracellular needle. Secretion is regulated by both cytoplasmic and inner membrane proteins that must respond to specific signals in order to ensure that virulence proteins are not secreted before contact with a eukaryotic cell. This negative regulation is mediated, in part, by a family of proteins that are thought to physically block the entrance to the secretion apparatus until an appropriate signal is received following host cell contact. Despite weak sequence homology between proteins of this family, the crystal structures of Shigella flexneri MxiC we present here confirm the conservation of domain topology with the homologue from Yersinia sp. Interestingly, comparison of the Shigella and Yersinia structures reveals a significant structural change that results in substantial domain re-arrangement and opening of one face of the molecule. The conservation of a negatively charged patch on this face suggests it may have a role in binding other components of the T3SS.
Keywords :
type 3 secretion system , Mxi , membrane extrusion of invasion plasmid antigens , Yop , Yersinia outer protein , T3SS
Journal title :
Journal of Molecular Biology
Serial Year :
2008
Journal title :
Journal of Molecular Biology
Record number :
1256442
Link To Document :
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