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A proteolytically truncated form of Shigella Flexneri IpaD
Structural highlights
FunctionIPAD_SHIFL Required for bacterial invasion of host cells. Controls IpaB and IpaC secretion, and the efficiency with which they are physically inserted into target cell membranes. These proteins are exported via TTSS to form a pore in the host membrane that allows the translocation of the other effectors into the host cytoplasm. Along with IpaB, is essential for both blocking secretion through the Mxi/Spa translocon in the absence of a secretion-inducing signal, and for controlling the level of secretion in the presence of this signal.[1] [2] 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 PubMedBacteria expressing type III secretion systems (T3SS) have been responsible for the deaths of millions worldwide, acting as key virulence elements in diseases ranging from plague to typhoid fever. The T3SS is composed of a basal body, which traverses both bacterial membranes, and an external needle through which effector proteins are secreted. We report multiple crystal structures of two proteins that sit at the tip of the needle and are essential for virulence: IpaD from Shigella flexneri and BipD from Burkholderia pseudomallei. The structures reveal that the N-terminal domains of the molecules are intramolecular chaperones that prevent premature oligomerization, as well as sharing structural homology with proteins involved in eukaryotic actin rearrangement. Crystal packing has allowed us to construct a model for the tip complex that is supported by mutations designed using the structure. Self-chaperoning of the type III secretion system needle tip proteins IpaD and BipD.,Johnson S, Roversi P, Espina M, Olive A, Deane JE, Birket S, Field T, Picking WD, Blocker AJ, Galyov EE, Picking WL, Lea SM J Biol Chem. 2007 Feb 9;282(6):4035-44. Epub 2006 Oct 31. PMID:17077085[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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