Oxidation of membrane-bound quinol molecules is a central step in the respiratory electron transport chains used by biological cells to generate ATP by oxidative phosphorylation. A novel family of cytochrome c quinol dehydrogenases that play an important role in bacterial respiratory chains was recognised in recent years ...
Oxidation of membrane-bound quinol molecules is a central step in the respiratory electron transport chains used by biological cells to generate ATP by oxidative phosphorylation. A novel family of cytochrome c quinol dehydrogenases that play an important role in bacterial respiratory chains was recognised in recent years. Here, we describe the first structure of a cytochrome from this family, NrfH from Desulfovibrio vulgaris, which forms a stable complex with its electron partner, the cytochrome c nitrite reductase NrfA. One NrfH molecule interacts with one NrfA dimer in an asymmetrical manner, forming a large membrane-bound complex with an overall alpha(4)beta(2) quaternary arrangement. The menaquinol-interacting NrfH haem is pentacoordinated, bound by a methionine from the CXXCHXM sequence, with an aspartate residue occupying the distal position. The NrfH haem that transfers electrons to NrfA has a lysine residue from the closest NrfA molecule as distal ligand. A likely menaquinol binding site, containing several conserved and essential residues, is identified.
Related Citations:
Crystallization and Preliminary Structure Determination of the Membrane-Bound Complex Cytochrome C Nitrite Reductase from Desulfovibrio Vulgaris Hildenborough Rodrigues, M.L., Oliveira, T., Matias, P.M., Martins, I.C., Valente, F.M.A., Pereira, I.A.C., Archer, M. (2006) Acta Crystallogr Sect F Struct Biol Cryst Commun 62: 565
Organizational Affiliation:
Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, ITQB-UNL, Oeiras, Portugal.
Download Mendeley
