Structure of the cobalamin‐binding protein of a putative O‐demethylase from Desulfitobacterium hafniense DCB‐2. (30th July 2013)

• Record Type: Journal Article
• Authors: Sjuts, Hanno; Dunstan, Mark S.; Fisher, Karl; Leys, David
• Is Part Of: Acta crystallographica. Volume 69:Part 8(2013:Aug.)
• Page Start: 1609
• Page End: 1616
• Publication Date: 2013-07-30
• Subjects: Biomolecules -- Structure -- Periodicals; Physical biochemistry -- Periodicals; X-ray crystallography -- Periodicals; Crystallography -- Periodicals; 572
• DOI: 10.1107/S0907444913011323
• Languages: English
• ISSNs: 0907-4449

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>This study describes the identification and the structural and spectroscopic analysis of a cobalamin‐binding protein (termed CobDH) implicated in <italic>O</italic>‐demethylation by the organohalide‐respiring bacterium <italic>Desulfitobacterium hafniense</italic> 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 <italic>O</italic>‐demethylation by <italic>D. hafniense</italic>.</p> </abstract>