Analysis of the proposed Fe-SX binding region of Photosystem 1 by site directed mutation of PsaA in Chlamydomonas reinhardtii
- 1 November 1995
- journal article
- Published by Springer Nature in Photosynthesis Research
- Vol. 46 (1) , 257-264
- https://doi.org/10.1007/bf00020438
Abstract
The psaA and psaB genes of the chloroplast genome in oxygenic photosynthetic organisms code for the major peptides of the Photosystem 1 reaction center. A heterodimer of the two polypeptides PsaA and PsaB is thought to bind the reaction center chlorophyll, P700, and the early electron acceptors A0, A1 and Fe-SX. Fe-SX is a 4Fe4S center requiring 4 cysteine residues as ligands from the protein. As PsaA and PsaB have only three and two conserved cysteine residues respectively, it has been proposed by several groups that Fe-SX is an unusual inter-peptide center liganded by two cysteines from each peptide. This hypothesis has been tested by site directed mutagenesis of PsaA residue C575 and the adjacent D576. The C575D mutant does not assemble Photosystem 1. The C575H mutant contains a photoxidisable chlorophyll with EPR properties of P700, but no other Photosystem 1 function has been detected. The D576L mutant assembles a modified Photosystem 1 in which the EPR properties of the Fe-SA/B centers are altered. The results confirm the importance of the conserved cysteine motif region in Photosystem 1 structure.Keywords
This publication has 37 references indexed in Scilit:
- Evidence That the FX Domain in Photosystem I Interacts with the Subunit PsaC: Site-Directed Changes in PsaB Destabilize the Subunit Interaction in Chlamydomonas reinhardtiiBiochemistry, 1995
- Path of Electron Transfer in Photosystem 1: Direct Evidence of Forward Electron Transfer from A1 to Fe-SXBiochemistry, 1994
- Site-directed conversion of cysteine-565 to serine in PsaB of photosystem I results in the assembly of iron-sulfur [3Fe-4S] and iron-sulfur [4Fe-4S] clusters in Fx. A mixed-ligand iron-sulfur [4Fe-4S] cluster is capable of electron transfer to FA and FBBiochemistry, 1993
- Three-dimensional structure of system I of photosynthesis at 6 Å resolutionNature, 1993
- Biochemical evidence for the role of the bound iron-sulphur centres A and B in NADP reduction by Photosystem IBiochimica et Biophysica Acta (BBA) - Bioenergetics, 1992
- Electron spin echo envelope modulation spectroscopy supports the suggested coordination of two histidine ligands to the Rieske iron-sulfur centers of the cytochrome b6f complex on spinach and the cytochrome bc1 complexes of Rhodospirillum rubrum, Rhodobacter sphaeroides R-26, and bovine heart mitochondriaBiochemistry, 1991
- Hörstadius and Beyond: The Neural Crest . Including a Facsimile Reprint of The Neural Crest by Sven Hörstadius. Brian K. Hall. Oxford University Press, New York, 1988. viii, 303 pp., illus. $60.Science, 1989
- Characterization of an isolated chloroplast membrane Fe◀S protein and its identification as the photosystem I Fe◀SA/Fe◀SB binding proteinFEBS Letters, 1988
- Photosystem I charge separation in the absence of centers A and B. I. Optical characterization of center ‘A2’ and evidence for its association with a 64-kDa peptideBiochimica et Biophysica Acta (BBA) - Bioenergetics, 1986