Structure of the Escherichia coli fumarate reductase respiratory complex.
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Iverson TM, Luna-Chavez C, Cecchini G, Rees DC
Structure of the Escherichia coli fumarate reductase respiratory complex.
Science. 1999 Jun 18;284(5422):1961-6.
- PubMed ID
- 10373108 [ View in PubMed]
- Abstract
The integral membrane protein fumarate reductase catalyzes the final step of anaerobic respiration when fumarate is the terminal electron acceptor. The homologous enzyme succinate dehydrogenase also plays a prominent role in cellular energetics as a member of the Krebs cycle and as complex II of the aerobic respiratory chain. Fumarate reductase consists of four subunits that contain a covalently linked flavin adenine dinucleotide, three different iron-sulfur clusters, and at least two quinones. The crystal structure of intact fumarate reductase has been solved at 3.3 angstrom resolution and demonstrates that the cofactors are arranged in a nearly linear manner from the membrane-bound quinone to the active site flavin. Although fumarate reductase is not associated with any proton-pumping function, the two quinones are positioned on opposite sides of the membrane in an arrangement similar to that of the Q-cycle organization observed for cytochrome bc1.