Molecular coevolution of the vertebrate cytochrome c1 and Rieske Iron Sulphur Protein in the cytochrome bc1 complex

Cytochrome c1 (cyt-c1) and the Rieske Iron Sulphur Protein (ISP) are subunits of the cytochrome bc1 complex located in the mitochondria functioning both as a proton pump and an electron transporter. Vertebrate model organism phylogenies were used in conjunction with existing 3D protein structures to evaluate the biochemical evolution of cyt-c1 and ISP in terms of selection on amino acid properties. We found selection acting on the exterior surfaces of both proteins and specifically the core region of cyt-c1. There is evidence supporting coevolution of these proteins relative to alpha helical tendencies, compressibility and equilibrium constant.