The critical role of tryptophan‐116 in the catalytic cycle of dimethylsulfoxide reductase from Rhodobacter capsulatus

FEBS Letters

McEwan, Alastair G²  Ridge, Justin P²  Aguey-Zinsou, Kondo-Francois³  Bernhardt, Paul V³  Hanson, Graeme R¹ 

[1] Centre for Magnetic Resonance, University of Queensland, Brisbane, Qld. 4072, Australia;Centre for Metals in Biology, School of Molecular and Microbial Sciences, University of Queensland, Brisbane, Qld. 4072, Australia;Department of Chemistry, School of Molecular and Microbial Sciences, University of Queensland, Brisbane, Qld. 4072, Australia

关键词: Dimethylsulfoxide reductase;    Molybdenum enzyme;    Site-directed mutagenesis;    Electrochemistry;    Rhodobacter capsulatus;    MPT;    molybdopterin;    DMSO;    dimethylsulfoxide;    MGD;    molybdopterin guanine dinucleotide;    NAP;    periplasmic nitrate reductase;    FDH;    formate dehydrogenase;    ASO;    arsenite oxidase;    TMAO;    trimethylamine-N-oxide;    MV;    methyl viologen;    DMS;    dimethylsulfide;    DCPIP;    dichlorophenol indophenol;    DDAB;    didodecyldimethylammonium bromide;    CSIRO;    Commonwealth Scientific and Industrial Research Organization;    ICP-MS;    inductively coupled plasma mass spectrometry;   

DOI  :  10.1016/S0014-5793(04)00301-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

In dimethylsulfoxide reductase of Rhodobacter capsulatus tryptophan-116 forms a hydrogen bond with a single oxo ligand bound to the molybdenum ion. Mutation of this residue to phenylalanine affected the UV/visible spectrum of the purified Mo^VI form of dimethylsulfoxide reductase resulting in the loss of the characteristic transition at 720 nm. Results of steady-state kinetic analysis and electrochemical studies suggest that tryptophan 116 plays a critical role in stabilizing the hexacoordinate monooxo Mo^VI form of the enzyme and prevents the formation of a dioxo pentacoordinate Mo^VI species, generated as a consequence of the dissociation of one of the dithiolene ligands of the molybdopterin cofactor from the Mo ion.

【 授权许可】

Unknown