In this section
@article{Hamilton:2014:pcp/pcu070,
author = {Hamilton, ML and Franco, E and Deák, Z and Schlodder, E and Vass, I and Nixon, PJ},
doi = {pcp/pcu070},
journal = {Plant and Cell Physiology},
pages = {1276--1285},
title = {Investigating the photoprotective role of cytochrome b-559 in photosystem II in a mutant with altered ligation of the haem},
url = {http://dx.doi.org/10.1093/pcp/pcu070},
volume = {55},
year = {2014}
}
TY - JOUR
AB - Despite many years of study, the physiological role of cytochrome b-559 (Cyt b-559) within the photosystem II (PSII) complex still remains unclear. Here we describe the analysis of a mutant of the green alga Chlamydomonas reinhardtii in which the His ligand to the haem, provided by the alpha subunit, has been replaced by a Cys residue. The mutant is unable to grow photoautotrophically but can assemble oxygen-evolving PSII supercomplexes to 15-20% of the levels found in the wild-type control. Haem is still detected in the isolated PSII supercomplexes but at sub-stoichiometric levels consistent with weaker binding to the mutated cytochrome. Analysis of PSII activity in cells indicates slowed electron transfer in the mutant between plastoquinones Q<inf>A</inf> and Q<inf>B</inf>. We show that PSII activity in the mutant is more sensitive to chronic photoinhibition than the WT control because of two effects: a faster rate of damage and an impaired PSII repair cycle at the level of synthesis and/or incorporation of D1 into PSII. We also demonstrate that Cyt b-559 plays a role during the critical stage of assembling the Mn <inf>4</inf>CaO<inf>5</inf> cluster. Overall we conclude that Cyt b-559 optimises electron transfer on the acceptor side of PSII and plays physiologically important roles in the assembly, repair and maintenance of the complex. © 2014 The Author 2014.
AU - Hamilton,ML
AU - Franco,E
AU - Deák,Z
AU - Schlodder,E
AU - Vass,I
AU - Nixon,PJ
DO - pcp/pcu070
EP - 1285
PY - 2014///
SN - 0032-0781
SP - 1276
TI - Investigating the photoprotective role of cytochrome b-559 in photosystem II in a mutant with altered ligation of the haem
T2 - Plant and Cell Physiology
UR - http://dx.doi.org/10.1093/pcp/pcu070
VL - 55
ER -