Research Of Yeast Cytochrome C Lethal Mutant Scc-m80a/f82h

Cytochrome C is a single chain protein, which widely exists in the mitochondriaof aerobic species. It plays extremely important role in the electron transfer, antioxi-dation and apoptosis. Therefore, it is important to understand its structure and biolog-ical function. The axial coordination of the iron in cytochrome C plays a major rolein determining the redox, electron transfer, and other properties of the protein, thusour research focused on the study of the axial coordination of cytochrome C. In ourprevious work, we have used site-directed mutagenesis technique to make several mu-tations around the axial coordination region and found most of them are lethal. Thelethal mutations provide very useful information as to the essentiality of some residues.However, it is difficult to express these mutant genes and make a reasonable amount ofprotein in yeast system. We successfully expressed large amount of lethal mutant sCc-M80A/F82H with bacterial system. By kinetic studies and other analysis, and contrastit with horse and yeast wild-type Cytochrome c, we found the mutant has a very dif-ferent structure and redox character compared to the wild-type. Further studies of thelethal mutant would clearly be of great importance to our understanding of structure-function relationship in cytochrome C.