2awy | pdb_00002awy
met-DcrH-Hr
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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
2AWY is a Single protein structure of sequence from Desulfovibrio vulgaris with CL, CA and FEO 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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