1fnb
REFINED CRYSTAL STRUCTURE OF SPINACH FERREDOXIN REDUCTASE AT 1.7 ANGSTROMS RESOLUTION: OXIDIZED, REDUCED, AND 2'-PHOSPHO-5'-AMP BOUND STATES
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| , resolution 1.7Å | |||||||
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| Ligands: | , , | ||||||
| Activity: | Ferredoxin--NADP(+) reductase, with EC number 1.18.1.2 | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
OverviewOverview
The crystal structure of spinach ferredoxin-NADP(+)-oxidoreductase (FNR), determined by multiple isomorphous replacement at 2.6 A resolution, has been refined at 1.7 A resolution to an R-factor of 17.9%. The structure of FNR bound to the competitive inhibitor 2'-phospho-5'-AMP (P-AMP) has also been refined at 1.7 A to an R-factor of 17.4% and dithionite-reduced/P-AMP-bound FNR has been refined at 2.0 A to an R-factor of 14.9%. The P-AMP-bound structure was used to construct a model for the binding of NADP+. Over 200 solvation sites were included in each structure, and many of the best defined solvation sites stabilize buried turns. A bulk solvent correction obviated the need for a low-resolution data cutoff. An acidic side-chain likely to be responsible for the low pH requirement for crystallization has been identified. Three large networks of the hydrophobic side-chains help define the FNR structure. One of these contains a large cavity far from the active site, which coincides with the lone site of sequence heterogeneity in FNR, and may provide a site for membrane attachment. The reduced structure shows that Ser96 moves toward atom N-5 of FAD and a water molecule moves toward atom N-1 of FAD, while the flavin moiety remains planar. Possible sources of a proton that must be picked up upon reduction are discussed.
About this StructureAbout this Structure
1FNB is a Single protein structure of sequence from Spinacia oleracea. This structure supersedes the now removed PDB entry 1FNR. Full crystallographic information is available from OCA.
ReferenceReference
Refined crystal structure of spinach ferredoxin reductase at 1.7 A resolution: oxidized, reduced and 2'-phospho-5'-AMP bound states., Bruns CM, Karplus PA, J Mol Biol. 1995 Mar 17;247(1):125-45. PMID:7897656
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