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Catalytic Site Atlas Version 2.2.12
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CSA entry for 1b2r
Original Entry
Title:
Oxidoreductase
Compound:
Ferredoxin-nadp+ reductase
Mutant:
Yes
UniProt/Swiss-Prot:
P21890-FENR_ANASO
EC Class:
1.18.1.2
Other CSA Entries:
Overview of all sites for 1b2r
Homologues of 1b2r
Entries for UniProt/Swiss-Prot: P21890
Entries for EC: 1.18.1.2
Other Databases:
PDB entry: 1b2r
PDBsum entry: 1b2r
UniProt/Swiss-Prot: P21890
IntEnz entry: 1.18.1.2
Literature Report:
Introduction:
Ferredoxin-NADP+ reductase (FNR), isolated from Anabaena PCC 7119, catalyses the reduction of NADP+ to NADPH using two molecules of ferredoxin (Fd) as the source of the electrons and FAD as a cofactor. This is the last step in linear photosynthesis.
Mechanism:
Fd transfers an electron to FAD via the pi-system of Phe65 of Fd. A proton is transferred from the hydroxyl group of Fd S54, through Glu301 and Ser80, to the isoalloxazine N5 position to produce neutral semiquinone. A second molecule of Fd transfers an electron to the semiquinone to produc anionic hydroquinone. A hydride is transferred from the N5 position of the hydroquinone to the C4 position of NADP+ to produce FAD and NADPH.
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Found by:
Literature reference 

ResidueChainNumberUniProt numberFunctional part FunctionTargetDescription
304 0Sidechain
Substrate
Electron donor/acceptorSubstrate
FAD accepts an electron from Fd and a proton from Ser80 to produce a neutral semiquinone. It then accepts an electron from another Fd molecule to form an anionic hydroquinone. The hydroquinone transfers a hydride to NADP+ to form NADPH and reform the FAD coafctor.
Evidence from paper Evidence concerns Evidence type
PubMed ID 11256611 Current protein Residue is positioned appropriately (ligand position known)
PubMed ID 17224127 Current protein Ligand is essential for catalysis
PubMed ID 8890910 Current protein Residue is positioned appropriately (ligand position known)
PubMed ID 12079352 Current protein Residue is positioned appropriately (ligand position known)
PubMed ID 17224127 Current protein Kinetic studies

ResidueChainNumberUniProt numberFunctional part FunctionTargetDescription
SERA 80 217Sidechain
Acid/baseCofactor
Ser80 is thought to act as part of a proton relay. It transfers a proton from Glu301 to the isoalloxazine N5 position of the semiquinone anion to produce neutral semiquinone.
Evidence from paper Evidence concerns Evidence type
PubMed ID 10651039 Current protein Conservation of residue
PubMed ID 8890910 Current protein Residue is positioned appropriately (ligand position known)

ResidueChainNumberUniProt numberFunctional part FunctionTargetDescription
ALAA 301 438Sidechain
ElectrostaticCofactor
Acid/baseResidue
Acid/baseSubstrate
Glu301 stabilises the semiquinone radical by forming a hydrogen bond to the isoalloxazine N5. It also destabilises the anionic hydroquinone and so acts to modify the FAD reduction potential. Glu301 is thought to act as part of a proton relay to form neutral semiquinone. It transfers a proton from the hydroxyl group of Fd S64 to Ser80.
Evidence from paper Evidence concerns Evidence type
PubMed ID 11256611 Current protein Residue is positioned appropriately (ligand position known)
PubMed ID 10651039 Current protein Mutagenesis of residue
PubMed ID 8890910 Current protein Residue is positioned appropriately (ligand position known)
PubMed ID 10651039 Current protein Conservation of residue
PubMed ID 12047373 Current protein Mutagenesis of residue
Notes:

References:
Which EBI biological databases are available and how do I access them? EBI Site Map