Structure and function of the bc-complex of Rhodobacter sphaeroides.

The ubiquinol:cytochrome c2 oxidoreductase (bc-complex) of Rhodobacter sphaeroides has three main subunits, which bear the prosthetic groups, and contribute to three catalytic sites and internal electron transfer pathways which define the modified Q-cycle mechanism. In this paper, we report on progress in modelling the structure of the bc-complex, and experiments using site directed mutagenesis and biophysical assay to probe the structural and function consequences of specific modifications to these subunits.