3tuf | pdb_00003tuf

Structure of the SpoIIQ-SpoIIIAH pore forming complex.

spinqualitylabelsall models 3tuf, resolution 2.26Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3tuf is a 2 chain structure with sequence from "bacillus_globigii"_migula_1900 "bacillus globigii" migula 1900. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Gene: BSU36550, spoIIQ, ywnI ("Bacillus globigii" Migula 1900), BSU24360, spoIIIAH ("Bacillus globigii" Migula 1900) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [SP2Q_BACSU] Involved in forespore engulfment and required for anchoring membrane proteins on the forespore side of the septal membrane. Forms a channel with SpoIIIAH that is open on the forespore end and closed (or gated) on the mother cell end. This allows sigma-E-directed gene expression in the mother-cell compartment of the sporangium to trigger the activation of sigma-G forespore-specific gene expression by a pathway of intercellular signaling. [SP3AH_BACSU] Involved in forespore engulfment. Forms a channel with SpoIIIAH that is open on the forespore end and closed (or gated) on the mother cell end. This allows sigma-E-directed gene expression in the mother-cell compartment of the sporangium to trigger the activation of sigma-G forespore-specific gene expression by a pathway of intercellular signaling. Publication Abstract from PubMed Following asymmetric cell division during spore formation in Bacillus subtilis, a forespore expressed membrane protein SpoIIQ, interacts across an intercellular space with a mother cell-expressed membrane protein, SpoIIIAH. Their interaction can serve as a molecular "ratchet" contributing to the migration of the mother cell membrane around that of the forespore in a phagocytosis-like process termed engulfment. Upon completion of engulfment, SpoIIQ and SpoIIIAH are integral components of a recently proposed intercellular channel allowing passage from the mother cell into the forespore of factors required for late gene expression in this compartment. Here we show that the extracellular domains of SpoIIQ and SpoIIIAH form a heterodimeric complex in solution. The crystal structure of this complex reveals that SpoIIQ has a LytM-like zinc-metalloprotease fold but with an incomplete zinc coordination sphere and no metal. SpoIIIAH has an alpha-helical subdomain and a protruding beta-sheet subdomain, which mediates interactions with SpoIIQ. SpoIIIAH has sequence and structural homology to EscJ, a type III secretion system protein that forms a 24-fold symmetric ring. Superposition of the structures of SpoIIIAH and EscJ reveals that the SpoIIIAH protomer overlaps with two adjacent protomers of EscJ, allowing us to generate a dodecameric SpoIIIAH ring by using structural homology. Following this superposition, the SpoIIQ chains also form a closed dodecameric ring abutting the SpoIIIAH ring, producing an assembly surrounding a 60 A channel. The dimensions and organization of the proposed complex suggest it is a plausible model for the extracellular component of a gap junction-like intercellular channel. Structure of components of an intercellular channel complex in sporulating Bacillus subtilis.,Levdikov VM, Blagova EV, McFeat A, Fogg MJ, Wilson KS, Wilkinson AJ Proc Natl Acad Sci U S A. 2012 Apr 3;109(14):5441-5. Epub 2012 Mar 19. PMID:22431604 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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