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Catalytic Site Atlas

CSA LITERATURE entry for 1b2r

E.C. nameferredoxin---NADP+ reductase
SpeciesAnabaena sp. (strain L31)
E.C. Number (IntEnz)
CSA Homologues of 1b2r
CSA Entries With UniProtID P21890
CSA Entries With EC Number
PDBe Entry 1b2r
PDBSum Entry 1b2r
MACiE Entry 1b2r

Literature Report

IntroductionFerredoxin-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.
MechansimFd 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.

Catalytic Sites for 1b2r

Annotated By Reference To The Literature - Site 2 (Perform Site Search)
ResidueChainNumberUniProtKB NumberFunctional PartFunctionTargetDescription
SerA80217macie:sideChainSer80 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.
AlaA301438macie:sideChainGlu301 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.

Literature References