Research Article

Molecular Basis of Proton Motive Force Generation: Structure of Formate Dehydrogenase-N

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Science  08 Mar 2002:
Vol. 295, Issue 5561, pp. 1863-1868
DOI: 10.1126/science.1068186

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The structure of the membrane protein formate dehydrogenase-N (Fdn-N), a major component of Escherichia coli nitrate respiration, has been determined at 1.6 angstroms. The structure demonstrates 11 redox centers, including molybdopterin-guanine dinucleotides, five [4Fe-4S] clusters, two heme b groups, and a menaquinone analog. These redox centers are aligned in a single chain, which extends almost 90 angstroms through the enzyme. The menaquinone reduction site associated with a possible proton pathway was also characterized. This structure provides critical insights into the proton motive force generation by redox loop, a common mechanism among a wide range of respiratory enzymes.

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