2ca5
MXIH NEEDLE PROTEIN OF SHIGELLA FLEXNERI (MONOMERIC FORM, RESIDUES 1-78)
OverviewOverview
Type III secretion systems are essential virulence determinants for many Gram-negative bacterial pathogens. The type III secretion system consists of cytoplasmic, transmembrane, and extracellular domains. The extracellular domain is a hollow needle protruding above the bacterial surface and is held within a basal body that traverses both bacterial membranes. Effector proteins are translocated, via this external needle, directly into host cells, where they subvert normal cell functions to aid infection. Physical contact with host cells initiates secretion and leads to formation of a pore, thought to be contiguous with the needle channel, in the host-cell membrane. Here, we report the crystal structure of the Shigella flexneri needle subunit MxiH and a complete model for the needle assembly built into our three-dimensional EM reconstruction. The model, combined with mutagenesis data, reveals that signaling of host-cell contact is relayed through the needle via intersubunit contacts and suggests a mode of binding for a tip complex.
About this StructureAbout this Structure
2CA5 is a Single protein structure of sequence from Shigella flexneri. Full crystallographic information is available from OCA.
ReferenceReference
Molecular model of a type III secretion system needle: Implications for host-cell sensing., Deane JE, Roversi P, Cordes FS, Johnson S, Kenjale R, Daniell S, Booy F, Picking WD, Picking WL, Blocker AJ, Lea SM, Proc Natl Acad Sci U S A. 2006 Aug 15;103(33):12529-33. Epub 2006 Aug 3. PMID:16888041 Page seeded by OCA on Sat May 3 21:33:26 2008