Effects of Humanizing Mutations on the Heme Crevice Loop of Yeast Iso-1-Cytochrome c

Abstract

Cytochrome c (Cytc) is a small, globular protein within the inner mitochondrial membrane that plays an important role in cellular energy production by facilitating electron transport. Upon release from the mitochondria, Cytc participates in initiation of the caspase cascade leading to apoptosis, or programmed cell death. On the inner mitochondria membrane, Cytc binds cardiolipin, leading to loss of Met80-heme ligation, enabling Cytc to function as a peroxidase capable of oxidizing cardiolipin. Cytc has decreased affinity for oxidized cardiolipin and therefore can dissociate from the membrane facilitating release from mitochondrial and propagation of apoptosis.