2AWC

deoxy-DcrH-Hr

Summary for 2AWC

• Entry DOI: 10.2210/pdb2awc/pdb
• Descriptor: hemerythrin-like domain protein DcrH, MU-OXO-DIIRON (3 entities in total)
• Functional Keywords: four helix bundle, oxygen storage-transport complex, oxygen storage/transport
• Biological source: Desulfovibrio vulgaris
• Total number of polymer chains: 1
• Total formula weight: 15715.38

Authors

Isaza, C.E.,Silaghi-Dumitrescu, R.,Iyer, R.B.,Kurtz, D.M.,Chan, M.K. (deposition date: 2005-08-31, release date: 2006-08-15, Last modification date: 2024-02-14)

Primary citation

Isaza, C.E.,Silaghi-Dumitrescu, R.,Iyer, R.B.,Kurtz, D.M.,Chan, M.K.
Structural Basis for O(2) Sensing by the Hemerythrin-like Domain of a Bacterial Chemotaxis Protein: Substrate Tunnel and Fluxional N Terminus
Biochemistry, 45:9023-9031, 2006

PubMed Abstract: 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).

PubMed: 16866347
DOI: 10.1021/bi0607812

Experimental method

X-RAY DIFFRACTION (2.2 Å)