Redox dependent conformational change of the 2Fe-2Sferredoxin revealed by ultrahigh resolution X-ray crystallography

摘要

Plant type ferredoxin (PtFd) is a small soluble protein which has a [2Fe-2S] cluster.PtFd at leaves acts as an electron transfer between photosystem I and Fd-dependent enzymessuch as Ferredoxin-NADP+ reductase (FNR).Redox-dependent structural change of Fdcontrols dissociation constant of Fd between Fd-dependent enzymes.This system wouldencourage smooth electron transfer.According to the previous research on the oxidized andreduced PtFd structures1,a peptide bond near the cluster was predicted to be flipped uponredox.Although no other structural change was defined.It should be because ofincompleteness of reduction of reduced PtFd or X-ray induced reduction of oxidized PtFd.We sure that strict structural analysis of oxidized and reduced Fd reveals the mechanism:how Fd change its own structure by one electron reduction and decrease affinity to Fddependentenzymes.