Joshua Jeffs, Utah Valley University
Chemistry
The electron transport chain (ETC) is a system within a cell that couples electron transfer between a donor and a receptor. The ETC is made up of several components, specifically: complexes one through four, a coenzyme Q, and a cytochrome complex. Cytochrome C oxidase (CcO), also known as complex IV, uses electrons and H_ ions to reduce molecular oxygen to water. CcO is made up of several subunits or proteins that are responsible for the function of CcO. The creation of CcO involves multiple steps that include many different gene products or proteins. (3) Of these proteins several are from a specific type of family called cysteine-X _-cysteine motifs (twin CX_C). The cysteine residues in the cysteine pairs are each spaced by nine residues. The best characterized protein of this group is Cox17, a copper-binding protein that plays a role in copper transfer to CcO. There are 14 potential proteins that are twin-Cx_C motifs (1). There were four knock out strains that showed resistance when plated on YPD with varying concentrations of hydrogen peroxide: 0.010%, 0.014%, 0.018%, and 0.022%. Strains lacking CMC4, MIC14, MIC17, and PET191 all showed resistance to hydrogen peroxide compared to the parental strain. Strains lacking MDM35 and COX23 showed sensitivity to hydrogen peroxide. These result may indicate a tie to impaired or incomplete cytochrome c oxidase assembly.