2bgj | pdb_00002bgj

X-RAY STRUCTURE OF THE FERREDOXIN-NADP(H) REDUCTASE FROM RHODOBACTER CAPSULATUS AT 2.1 ANGSTROMS

spinqualitylabelsall models 2bgj, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2bgj is a 4 chain structure with sequence from Rhodobacter capsulatus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: FAD Related: 2bgi Activity: Ferredoxin--NADP(+) reductase, with EC number 1.18.1.2 Resources: FirstGlance, OCA, RCSB, PDBsum 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 PubMed The photosynthetic bacterium Rhodobacter capsulatus contains a ferredoxin (flavodoxin)-NADP(H) oxidoreductase (FPR) that catalyzes electron transfer between NADP(H) and ferredoxin or flavodoxin. The structure of the enzyme, determined by X-ray crystallography, contains two domains harboring the FAD and NADP(H) binding sites, as is typical of the FPR structural family. The FAD molecule is in a hairpin conformation in which stacking interactions can be established between the dimethylisoalloxazine and adenine moieties. The midpoint redox potentials of the various transitions undergone by R. capsulatus FPR were similar to those reported for their counterparts involved in oxygenic photosynthesis, but its catalytic activity is orders of magnitude lower (1-2 s(-)(1) versus 200-500 s(-)(1)) as is true for most of its prokaryotic homologues. To identify the mechanistic basis for the slow turnover in the bacterial enzymes, we dissected the R. capsulatus FPR reaction into hydride transfer and electron transfer steps, and determined their rates using stopped-flow methods. Hydride exchange between the enzyme and NADP(H) occurred at 30-150 s(-)(1), indicating that this half-reaction does not limit FPR activity. In contrast, electron transfer to flavodoxin proceeds at 2.7 s(-)(1), in the range of steady-state catalysis. Flavodoxin semiquinone was a better electron acceptor for FPR than oxidized flavodoxin under both single turnover and steady-state conditions. The results indicate that one-electron reduction of oxidized flavodoxin limits the enzyme activity in vitro, and support the notion that flavodoxin oscillates between the semiquinone and fully reduced states when FPR operates in vivo. The ferredoxin-NADP(H) reductase from Rhodobacter capsulatus: molecular structure and catalytic mechanism.,Nogues I, Perez-Dorado I, Frago S, Bittel C, Mayhew SG, Gomez-Moreno C, Hermoso JA, Medina M, Cortez N, Carrillo N Biochemistry. 2005 Sep 6;44(35):11730-40. PMID:16128574 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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