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Effects of ultraviolet-B radiation on photosystem II of the cyanobacterium Synechocystis sp. PCC 6083.
- Source :
-
European journal of biochemistry [Eur J Biochem] 1996 Dec 15; Vol. 242 (3), pp. 799-806. - Publication Year :
- 1996
-
Abstract
- The effects of ultraviolet-B radiation (280-320 nm) on photosystem II of Synechocystis sp. PCC 6303 were investigated at the functional and structural levels. Loss of oxygen-evolving and electron-transport activity, measured by various techniques including Clark electrode polarography, fluorescence induction and fluorescence relaxation after a single turnover flash, are discussed in terms of two types of damage caused by ultraviolet-B radiation: (a) depletion of the plastoquinone pool; (b) perturbation and degradation of the D1 protein, with cleavage in the second transmembrane segment. These findings are in full agreement with those obtained, both in vivo and in vitro for higher plants for which a donor-side mechanism involving the water-splitting Mn cluster has been proposed for the main cleavage of the D1 protein. At the structural level, complete disruption of the photosystem II core is documented as a consequence of (or in parallel with) degradation of the D1 protein. From this point of view, ultraviolet-B-induced photoinhibition is unlike the visible-induced type and less susceptible to repair by synthesis and reinsertion of new D1 protein.
- Subjects :
- Chloroplasts chemistry
Manganese metabolism
Molecular Weight
Oxygen metabolism
Photosynthesis
Photosystem II Protein Complex
Plastoquinone metabolism
Protein Denaturation radiation effects
Spectrometry, Fluorescence
Ultraviolet Rays
Cyanobacteria radiation effects
Photosynthetic Reaction Center Complex Proteins radiation effects
Subjects
Details
- Language :
- English
- ISSN :
- 0014-2956
- Volume :
- 242
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- European journal of biochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 9022712
- Full Text :
- https://doi.org/10.1111/j.1432-1033.1996.0799r.x