
TY  - JOUR
A1  - Bergantino, Elisabetta 
A1  - Brunetta, Alessia 
A1  - Segalla, Anna 
A1  - Szabò, Ildikò 
A1  - Carbonera, Donatella 
A1  - Bordignon, Enrica 
A1  - Rigoni, Fernanda 
A1  - Giacometti, Giorgio M. 
T1  - Structural and functional role of the PsbH protein in resistance to light stress in <emph type="2">Synechocystis</emph> PCC 6803
JF  - Functional Plant Biology
JO  - Functional Plant Biol.
Y1  - 2002
VL  - 29
IS  - 10
SP  - 1181
EP  - 1187
KW  - 
UR  - https://doi.org/10.1071/FP02021 
N2  - Four mutants of the cyanobacterium Synechocystis sp. PCC 6803, carrying a modified PsbH subunit on a PSI-less background, were characterized by optically-detected magnetic resonance (ODMR), electron transport kinetics, and oxygen-evolving activity. Their relative tolerance to light stress was measured. Results indicate that: (i) the PsbH protein is deeply involved in determining structural and functional properties of the QB site on the D1 protein, whereas the environment of the primary donor P680 and its acceptors pheophytin and QA are not significantly affected by modifications of this subunit or its deletion; (ii) the charge recombination rate, in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), is reduced by a factor of 2, independently of the particular modification. The same result is found with the strain in which the subunit has been deleted. This result is taken as an indication that PsbH is important in regulating protein dynamics of the entire PSII core complex; (iii) all investigated mutants display reduced tolerance to light stress, the extent of which depends on the particular modification. In this respect, mutations introduced in the transmembrane portion of the polypeptide are more effective than those involving the extramembrane N-terminal extension. 
ER  -

