Multicopper manganese oxidase accessory proteins bind Cu and heme

摘要: Multicopper oxidases (MCOs) catalyze the oxidation of a diverse group metal ions and organic substrates by successive single-electron transfers to O2 via four bound Cu ions. MnxG, which catalyzes MnO2 mineralization oxidizing both Mn(II) Mn(III), is unique among multicopper in that it carries out two energetically distinct electron tightly accessory proteins. There are these, MnxE MnxF, approximately 12kDa. Although their sequences similar those found genomes several Mn-oxidizing Bacillus species, they dissimilar proteins with known function. Here, MnxF co-expressed independent MnxG oligomerize into higher order stoichiometry, likely hexamer. They bind copper heme, have been characterized paramagnetic resonance (EPR), X-ray absorption spectroscopy (XAS), UV-visible (UV-vis) spectrophotometry. type 2 (T2) centers, one appears be novel; heme as low-spin implying coordination axial ligands. do not oxidize Mn absence first required an MCO. This may indicate play roles transfer and/or trafficking.