Formation of Hexacoordinate Mn(III) in Bacillus subtilis Oxalate Decarboxylase Requires Catalytic Turnover.

ABSTRACT: Oxalate decarboxylase (OxDC) catalyzes the disproportionation of oxalic acid monoanion into CO2 and formate. The enzyme has long been hypothesized to utilize dioxygen to form mononuclear Mn(III) or Mn(IV) in the catalytic site during turnover. Recombinant OxDC, however, contains only tightly bound Mn(II), and direct spectroscopic detection of the metal in higher oxidation states under optimal catalytic conditions (pH 4.2) has not yet been reported. Using parallel mode electron paramagnetic resonance spectroscopy, we now show that substantial amounts of Mn(III) are indeed formed in OxDC, but only in the presence of oxalate and dioxygen under acidic conditions. These observations provide the first direct support for proposals in which Mn(III) removes an electron from the substrate to yield a

SUBMITTER: Zhu W 

PROVIDER: S-EPMC8183094 | biostudies-literature | 2016 Jan

REPOSITORIES: biostudies-literature