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Structure of the cobalamin-binding protein of a putative O-demethylase from Desulfitobacterium hafniense DCB-2

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...

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Detalles Bibliográficos
Autores principales: Sjuts, Hanno, Dunstan, Mark S., Fisher, Karl, Leys, David
Formato: Online Artículo Texto
Lenguaje:English
Publicado: International Union of Crystallography 2013
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3727330/
https://www.ncbi.nlm.nih.gov/pubmed/23897483
http://dx.doi.org/10.1107/S0907444913011323
Descripción
Sumario: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.