3fcg

Crystal Structure Analysis of the Middle Domain of the Caf1A Usher

spinqualitylabelsall models 3fcg, resolution 2.85Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3fcg is a 2 chain structure with sequence from Yersinia pestis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.85Å Ligands: CL Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function CAF1A_YERPE A probable role in capsular biogenesis. It is likely that the caf1A molecule binds F1 antigen subunits during the extracellular secretion process. 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 PubMed The chaperone/usher pathway controls assembly of fibres of adhesive organelles of Gram-negative bacteria. The final steps of fibre assembly and fibre translocation to the cell surface are co-ordinated by the outer membrane proteins, ushers. Ushers consist of several soluble periplasmic domains and a single transmembrane beta-barrel. Here we report isolation and structural/functional characterization of a novel middle domain of the Caf1A usher from Yersinia pestis. The isolated UMD (usher middle domain) is a highly soluble monomeric protein capable of autonomous folding. A 2.8 A (1 A=0.1 nm) resolution crystal structure of UMD revealed that this domain has an immunoglobulin-like fold similar to that of donor-strand-complemented Caf1 fibre subunit. Moreover, these proteins displayed significant structural similarity. Although UMD is in the middle of the predicted amphipathic beta-barrel of Caf1A, the usher still assembled in the membrane in the absence of this domain. UMD did not bind Caf1M-Caf1 complexes, but its presence was shown to be essential for Caf1 fibre secretion. The study suggests that UMD may play the role of a subunit-substituting protein (dummy subunit), plugging or priming secretion through the channel in the Caf1A usher. Comparison of isolated UMD with the recent structure of the corresponding domain of PapC usher revealed high similarity of the core structures, suggesting a universal structural adaptation of FGL (F(1)G(1) long) and FGS (F(1)G(1) short) chaperone/usher pathways for the secretion of different types of fibres. The functional role of two topologically different states of this plug domain suggested by structural and biochemical results is discussed. Caf1A usher possesses a Caf1 subunit-like domain that is crucial for Caf1 fibre secretion.,Yu X, Visweswaran GR, Duck Z, Marupakula S, MacIntyre S, Knight SD, Zavialov AV Biochem J. 2009 Mar 15;418(3):541-51. PMID:19032149 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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