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2avk
From Proteopedia
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(New page: 200px<br /><applet load="2avk" size="350" color="white" frame="true" align="right" spinBox="true" caption="2avk, resolution 1.530Å" /> '''met-azido-DcrH-Hr''...)
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Revision as of 16:10, 29 January 2008
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met-azido-DcrH-Hr
Overview
The methyl-accepting chemotaxis protein, DcrH, from the anaerobic, sulfate-reducing bacterium, Desulfovibrio vulgaris (Hildenborough), has a, hemerythrin-like domain, DcrH-Hr, at its C terminus. DcrH-Hr was, previously shown to contain a diiron site that binds O2, suggesting an, O2-sensing function. X-ray crystal structures of diferric (met-), azido-diferric (azidomet-), and diferrous (deoxy-) DcrH-Hr reveal a, "substrate tunnel" distinct from that in invertebrate hemerythrins. This, tunnel is proposed to facilitate the rapid autoxidation of oxy-DcrH-Hr and, suggests that sensing is triggered by O2 binding and subsequent oxidation, of the diferrous active site. The N-terminal loop of DcrH-Hr is highly, ordered in both met- and azidomet-DcrH-Hr but is disordered in, deoxy-DcrH-Hr. These redox-dependent conformational differences presumably, transduce the sensory signal of DcrH-Hr to the neighboring methylation, domain in the full-length receptor. Given the putative cytoplasmic, localization of its Hr-like O2-sensing domain, DcrH is proposed to serve a, role in negative aerotaxis (anaerotaxis).
About this Structure
2AVK is a Single protein structure of sequence from Desulfovibrio vulgaris with and as ligands. Full crystallographic information is available from OCA.
Reference
Structural basis for O2 sensing by the hemerythrin-like domain of a bacterial chemotaxis protein: substrate tunnel and fluxional N terminus., Isaza CE, Silaghi-Dumitrescu R, Iyer RB, Kurtz DM Jr, Chan MK, Biochemistry. 2006 Aug 1;45(30):9023-31. PMID:16866347
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