Methylobacillus flagellatus KT contains a novel cbo-type cytochrome oxidase

The o-type oxidase from the methanol-grown obligate methylotroph Methylobac illus flagellatus KT has been purified to homogeneity. The complex is compo sed of four subunits (57, 40, 35 and 30 kDa). It contains six haems (4C:1B: 1O) and one copper atom per molecule. It is proposed that the haem O-Cu-B b inuclear centre and a low-spin haem B are located in subunit I (57 kDa), tw o haems C reside in the cytochrome c homodimer (35 kDa), two haems C belong to the dihaem cytochrome c (30 kDa). The presented data provide evidence t hat cytochrome cbo is a novel representative of the haem-copper oxidase sup erfamily. (C) 2001 Published by Elsevier Science B.V. on behalf of the Fede ration of European Biochemical Societies.