Jd. Rochaix et al., Chloroplast site-directed mutagenesis of photosystem I in Chlamydomonas: Electron transfer reactions and light sensitivity, BIOCHIMIE, 82(6-7), 2000, pp. 635-645
The photosystem I (PSI) complex is a multisubunit protein-pigment complex e
mbedded in the thylakoid membrane which acts as a light-driven plastocyanin
/cytochrome c(6)-ferredoxin oxido-reductase. The use of chloroplast transfo
rmation and site-directed mutagenesis coupled with the biochemical and biop
hysical analysis of mutants of the green alga Chlamydomonas reinhardtii wit
h specific amino acid changes in several subunits of PSI has provided new i
nsights into the structure-function relationship of this important photosyn
thetic complex. In particular, this molecular-genetic analysis has identifi
ed key residues of the reaction center polypeptides of PSI which are the li
gands of some of the redox cofactors and it has also provided important ins
ights into the orientation of the terminal electron accepters of this compl
ex. Finally this analysis has also shown that mutations affecting the donor
side of PSI are limiting for overall electron transfer under high light an
d that electron trapping within the terminal electron accepters of PSI is h
ighly deleterious to the cells. (C) 2000 Societe francaise de biochimie ct
biologie moleculaire / Editions scientifiques et medicales Elsevier SAS.