1qjd
FLAVOCYTOCHROME C3 FROM SHEWANELLA FRIGIDIMARINA
OverviewOverview
The 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.
About this StructureAbout this Structure
1QJD is a Single protein structure of sequence from Shewanella frigidimarina. Full crystallographic information is available from OCA.
ReferenceReference
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 Page seeded by OCA on Sat May 3 06:20:43 2008