3s0m | pdb_00003s0m

A Structural Element that Modulates Proton-Coupled Electron Transfer in Oxalate Decarboxylase

spinqualitylabelsall models 3s0m, resolution 2.31Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3s0m is a 1 chain structure with sequence from "vibrio_subtilis"_ehrenberg_1835 "vibrio subtilis" ehrenberg 1835. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CO3, EDO, MN, PEG Related: 1j58 Gene: BSU33240, oxalate decarboxylase, oxdC, yvrK ("Vibrio subtilis" Ehrenberg 1835) Activity: Oxalate decarboxylase, with EC number 4.1.1.2 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [OXDC_BACSU] Converts oxalate to formate and CO(2) in an O(2)-dependent reaction. Can also catalyze minor side reactions: oxalate oxidation to produce H(2)O(2), and oxalate-dependent, H(2)O(2)-independent dye oxidations. Publication Abstract from PubMed The conformational properties of an active-site loop segment, defined by residues Ser(161)-Glu(162)-Asn(163)-Ser(164), have been shown to be important for modulating the intrinsic reactivity of Mn(II) in the active site of Bacillus subtilis oxalate decarboxylase. We now detail the functional and structural consequences of removing a conserved Arg/Thr hydrogen-bonding interaction by site-specific mutagenesis. Hence, substitution of Thr-165 by a valine residue gives an OxDC variant (T165V) that exhibits impaired catalytic activity. Heavy-atom isotope effect measurements, in combination with the X-ray crystal structure of the T165V OxDC variant, demonstrate that the conserved Arg/Thr hydrogen bond is important for correctly locating the side chain of Glu-162, which mediates a proton-coupled electron transfer (PCET) step prior to decarboxylation in the catalytically competent form of OxDC. In addition, we show that the T165V OxDC variant exhibits a lower level of oxalate consumption per dioxygen molecule, consistent with the predictions of recent spin-trapping experiments [Imaram et al. (2011) Free Radicals Biol. Med. 50, 1009-1015]. This finding implies that dioxygen might participate as a reversible electron sink in two putative PCET steps and is not merely used to generate a protein-based radical or oxidized metal center. A structural element that facilitates proton-coupled electron transfer in oxalate decarboxylase.,Saylor BT, Reinhardt LA, Lu Z, Shukla MS, Nguyen L, Cleland WW, Angerhofer A, Allen KN, Richards NG Biochemistry. 2012 Apr 3;51(13):2911-20. Epub 2012 Mar 19. PMID:22404040 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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