Figure 1.

Structure of the bovine cytochrome b sequences (pdb code: 1PPJ; ISP, iron–sulphur protein) [23]. The amino acids corresponding to the non-synonymous sites in the killer whales are displayed in orange and the positively selected sites (193 and 279) are coloured by atom type (red, oxygen; blue, carbon; yellow, nitrogen; the alanine and threonine side chains are represented as solid and transparent cylinders, respectively). The prosthetic groups are represented in black, and bound inhibitors in brown (ant, antimycin; stig, stigmatellin). Exercise intolerance in humans is associated with genetic variants at the sites shown in yellow [5].