1qjd
From Proteopedia
Flavocytochrome C3 from Shewanella frigidimarina
Structural highlights
FunctionFCCA_SHEFN Flavocytochrome that catalyzes the reduction of fumarate to succinate (PubMed:8093012). Is essential for fumarate respiration during anaerobic growth, acting as the terminal reductase (PubMed:9579067). Receives electrons from the membrane-bound tetraheme c-type cytochrome CymA (By similarity). Is essentially unidirectional, catalyzing only fumarate reduction (PubMed:8093012). Cannot reduce nitrite, dimethylsulphoxide, trimethylamine-N-oxide (TMAO) or sulfite (PubMed:8093012). In vitro, can use the artificial electron donor methyl viologen (PubMed:8093012).[UniProtKB:P83223][1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe 1.8 A resolution crystal structure of the tetraheme flavocytochrome c3, Fcc3, provides the first mechanistic insight into respiratory fumarate reductases or succinate dehydrogenases. The multi-redox center, three-domain protein shows a 40 A long 'molecular wire' allowing rapid conduction of electrons through a new type of cytochrome domain onto the active site flavin, driving the reduction of fumarate to succinate. In this structure a malate-like molecule is trapped in the enzyme active site. The interactions between this molecule and the enzyme suggest a clear mechanism for fumarate reduction in which the substrate is polarized and twisted, facilitating hydride transfer from the reduced flavin and subsequent proton transfer. The enzyme active site in the oxidized form is completely buried at the interface between the flavin-binding and the clamp domains. Movement of the cytochrome and clamp domains is postulated to allow release of the product. Structural and mechanistic mapping of a unique fumarate reductase.,Taylor P, Pealing SL, Reid GA, Chapman SK, Walkinshaw MD Nat Struct Biol. 1999 Dec;6(12):1108-12. PMID:10581550[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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