NMR reveals double occupancy of quinone-type ligands in the catalytic quinone binding site of the Na+-translocating NADH: Quinone oxidoreductase from vibrio cholerae

Abstract

Background: The Na+-NQR is a respiratory Na+ pump found in prokaryotes. Results: The NqrA subunit binds two quinone-type ligands in direct vicinity to each other. Conclusion: Simultaneous binding of two quinones enhances catalytic efficiency of the final electron transfer step. Significance: We provide the first direct experimental evidence of simultaneous quinone binding with relevance for the catalytic mechanism. © 2013 by The American Society for Biochemistry and Molecular Biology, Inc.