*6.2. The CI+CIII<sup>2</sup> SC*

CI can also assemble with the CIII dimer alone to form the CI+CIII<sup>2</sup> SC. Recently, a functional CI+CIII<sup>2</sup> SC has been isolated from ovine heart mitochondria and characterized by cryoEM, demonstrating that the contacts between CI and CIII<sup>2</sup> are evolutionarily conserved [72] and are similar to those of the respirasome, confirming the stabilizing role of CIII<sup>2</sup> on CI [69,74].
