Disintegration of phycobilisomes in a rice field cyanobacterium Nostoc sp. following UV irradiation.
The effects of ultraviolet-B (UV-B, 280-315 nm) irradiation on survival, growth and phycobilisome assembly have been studied in the N2-fixing cyanobacterium Nostoc sp. Survival and growth were virtually arrested after 120 min of UV irradiation. The phycobiliprotein fractions showed a decrease in absorption and fluorescence as well as a shift towards shorter wavelengths indicating the impairment of energy transfer from phycobiliproteins to the photosynthetic reaction centers. This was further supported by SDS-PAGE analysis of the fractions which revealed a loss in high molecular mass rod-core and core-membrane linker polypeptides. Also the low molecular mass phycobilin (alpha beta) monomers decreased, showing that the supra-molecular organization of the phycobilisomes disintegrated during UV irradiation.
Sinha
R P
RP
Institut für Botanik und Pharmazeutische Biologie, Friedrich-Alexander Universität, Erlangen, Fed. Rep. Germany.
Lebert
M
M
Kumar
A
A
Kumar
H D
HD
Häder
D P
DP
D001426:Bacterial Proteins / Q000528:radiation effects*; D000458:Cyanobacteria / Q000254:growth & development / Q000378:metabolism / Q000528:radiation effects*; D045342:Light-Harvesting Protein Complexes; D045524:Phycobilisomes; D010940:Plant Proteins / Q000528:radiation effects*; D014466:Ultraviolet Rays
D001426:Bacterial Proteins; D045342:Light-Harvesting Protein Complexes; D045524:Phycobilisomes; D010940:Plant Proteins