Project title: Combining EPR spectroscopy and site-directed mutagenesis to investigate the mechanism of respiratory complex I
Summary: Complex I is one of the most important components in the respiratory chain of mitochondria, but its mechanism is still poorly understood. The enzyme oxidizes NADH, delivers electrons through a long chain of Fe-S clusters and reduces ubiquinone. Concomitantly, protons are pumped into the mitochondrial matrix and complex I thus contributes to the proton-motive force that is crucial for the ATP synthesis. Recent advances point to the mechanistic relevance of several residues in the vicinity Fe-S cluster N2 (the terminal electron accept in the electron-transfer chain) and around the quinone binding pocket. By combining site-directed mutagenesis and EPR spectroscopy, the mechanistic relevance of these residues will be tested, ultimately leading to a better understanding of the enegy-coupling mechanism in complex I.