Structure of the cobalamin-binding protein of a putative O-demethylase from Desulfitobacterium hafniense DCB-2
- University of Manchester, 131 Princess Street, Manchester M1 7DN (United Kingdom)
The first crystal structure of the vitamin B12-binding protein from a three-component O-demethylase enzyme system is reported. During O-demethylation methyl groups are transferred from phenyl methyl ethers to tetrahydrofolate via methyl-B12 intermediates. This study describes the identification and the structural and spectroscopic analysis of a cobalamin-binding protein (termed CobDH) implicated in O-demethylation by the organohalide-respiring bacterium Desulfitobacterium hafniense DCB-2. The 1.5 Å resolution crystal structure of CobDH is presented in the cobalamin-bound state and reveals that the protein is composed of an N-terminal helix-bundle domain and a C-terminal Rossmann-fold domain, with the cobalamin coordinated in the base-off/His-on conformation similar to other cobalamin-binding domains that catalyse methyl-transfer reactions. EPR spectroscopy of CobDH confirms cobalamin binding and reveals the presence of a cob(III)alamin superoxide, indicating binding of oxygen to the fully oxidized cofactor. These data provide the first structural insights into the methyltransferase reactions that occur during O-demethylation by D. hafniense.
- OSTI ID:
- 22347819
- Journal Information:
- Acta Crystallographica. Section D: Biological Crystallography, Vol. 69, Issue Pt 8; Other Information: PMCID: PMC3727330; PMID: 23897483; PUBLISHER-ID: be5232; OAI: oai:pubmedcentral.nih.gov:3727330; Copyright (c) Sjuts et al. 2013; This is an open-access article distributed under the terms of the Creative Commons Attribution Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0907-4449
- Country of Publication:
- Denmark
- Language:
- English
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