The alternative complex III from Rhodothermus marinus – A prototype of a new family of quinol:electron acceptor oxidoreductases

Abstract 

The biochemical and genetic search for a bc₁ complex in Rhodothermus marinus was always fruitless; however, a functional equivalent, i.e. having quinol:cytochrome c oxidoreductase activity was characterized. Now, with the sequencing of R. marinus genome, it was possible to assign the N-terminal sequences of several proteins of this complex to its coding genes. The alternative complex III from R. marinus has the same genomic organization of the so-called MFIcc complexes, proposed to be oxidoreductases of the respiratory and photosynthetic electron transfer chains. In this report, we establish undoubtedly the existence of an alternative complex III, a functional substitute of the bc₁ complex, by its identification at both the biochemical and genomic level.

Keywords: MFIcc, Complex III, bc₁ Complex, Oxygen reductase