1opx
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(New page: 200px<br /><applet load="1opx" size="450" color="white" frame="true" align="right" spinBox="true" caption="1opx, resolution 2.80Å" /> '''Crystal structure of...)
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Revision as of 23:07, 24 November 2007
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Crystal structure of the traffic ATPase (HP0525) of the Helicobacter pylori type IV secretion system bound by sulfate
Overview
The coupling of ATP binding/hydrolysis to macromolecular secretion systems, is crucial to the pathogenicity of Gram-negative bacteria. We reported, previously the structure of the ADP-bound form of the hexameric traffic, VirB11 ATPase of the Helicobacter pylori type IV secretion system (named, HP0525), and proposed that it functions as a gating molecule at the inner, membrane, cycling through closed and open forms regulated by ATP, binding/hydrolysis. Here, we combine crystal structures with analytical, ultracentrifugation experiments to show that VirB11 ATPases indeed, function as dynamic hexameric assemblies. In the absence of nucleotide, the N-terminal domains exhibit a collection of rigid-body conformations., Nucleotide binding 'locks' the hexamer into a symmetric and compact, structure. We propose that VirB11s use the mechanical leverage generated, by such nucleotide-dependent conformational changes to facilitate the, export of substrates or the assembly of the type IV secretion apparatus., Biochemical characterization of mutant forms of HP0525 coupled with, electron microscopy and in vivo assays support such hypothesis, and, establish the relevance of VirB11s ATPases as drug targets against, pathogenic bacteria.
About this Structure
1OPX is a Single protein structure of sequence from Helicobacter pylori 26695 with SO4 and 2PE as ligands. Full crystallographic information is available from OCA.
Reference
VirB11 ATPases are dynamic hexameric assemblies: new insights into bacterial type IV secretion., Savvides SN, Yeo HJ, Beck MR, Blaesing F, Lurz R, Lanka E, Buhrdorf R, Fischer W, Haas R, Waksman G, EMBO J. 2003 May 1;22(9):1969-80. PMID:12727865
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