title: MauG: a di-heme enzyme required for methylamine dehydrogenase maturation.
abstract: Methylamine dehydrogenase (MADH) requires the cofactor tryptophan tryptophylquinone (TTQ) for activity. TTQ is a posttranslational modification that results from an 8-electron oxidation of two specific tryptophans in the MADH β-subunit. The final 6-electron oxidation is catalyzed by an unusual c-type di-heme enzyme, MauG. The di-ferric enzyme can react with H(2)O(2), but atypically for c-type hemes the di-ferrous enzyme can react with O(2) as well. In both cases, an unprecedented bis-Fe(IV) redox state is formed, composed of a ferryl heme (Fe(IV)=O) with the second heme as Fe(IV) stabilized by His-Tyr axial ligation. Bis-Fe(IV) MauG acts as a potent 2-electron oxidant. Catalysis is long-range and requires a hole hopping electron transfer mechanism. This review highlights the current knowledge and focus of research into this fascinating system.
authors.affiliation: Department of Biochemistry, Molecular Biology and Biophysics, Minneapolis, Minnesota 55455, USA. wilmo004@umn.edu
authors.forename: Carrie M
authors.initials: CM
authors.lastname: Wilmot
authors.forename: Erik T
authors.initials: ET
authors.lastname: Yukl
mesh_terms: D018360:Crystallography, X-Ray; D004579:Electron Transport; D010450:Endopeptidases / Q000737:chemistry* / Q000378:metabolism*; D006418:Heme; D045563:Indolequinones / Q000096:biosynthesis; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000378:metabolism*; D014364:Tryptophan / Q000031:analogs & derivatives / Q000096:biosynthesis
chemical_list: D045563:Indolequinones; C070569:tryptophan tryptophylquinone; D006418:Heme; D014364:Tryptophan; C021567:methylamine dehydrogenase; D000587:Oxidoreductases Acting on CH-NH Group Donors; D010450:Endopeptidases; C065481:Bacillus polymyxa proteinase