Light Intensity Adaptation and Phycobilisome Composition of Microcystis aeruginosa.

Phycobilisomes isolated from Microcystis aeruginosa grown to midlog at high light (270 microeinsteins per square meter per second) or at low light intensities (40 microeinsteins per square meter per second) were found to be identical. Electron micrographs established that they have a triangular central core apparently consisting of three allophycocyanin trimers surrounded by six rods, each composed of two hexameric phycocyanin molecules. The apparent mass of a phycobilisome obtained by gel filtration is 2.96 x 10(6) daltons. The molar ratio of the phycobiliproteins per phycobilisome is 12 phycocyanin hexamers:9 allophycocyanin trimers. The electron microscopic observations combined with the phycobilisome apparent mass and the phycobiliprotein stoichiometry data indicate that M. aeruginosa phycobilisomes are composed of a triangular central core of three stacks of three allophycocyanin trimers and six rods each containing two phycocyanin hexamers. Adaptation of M. aeruginosa to high light intensity results in a decrease in the number of phycobilisomes per cell with no alteration in phycobilisome composition or structure.

[1]  H. Siegelman,et al.  Preparation of calcium phosphate for protein chromatography. , 1965, Analytical biochemistry.

[2]  B. Zilinskas,et al.  Allophycocyanin from Nostoc sp. phycobilisomes. Properties and amino acid sequence at the NH2 terminus of the alpha and beta subunits of allophycocyanins I, II, and III. , 1980, The Journal of biological chemistry.

[3]  M. A. Hayat,et al.  Fixation for Electron Microscopy , 1982 .

[4]  M. Shilo,et al.  Photooxidation of cyanobacteria in natural conditions , 1976, Applied and environmental microbiology.

[5]  P. Falkowski,et al.  Adaptation of the Cyanobacterium Microcystis aeruginosa to Light Intensity. , 1983, Plant physiology.

[6]  J. Myers,et al.  ACTION SPECTRA FOR PHOTOREACTIONS I AND II OF PHOTOSYNTHESIS IN THE BLUE‐GREEN ALGA ANACYSTIS NIDULANS , 1977 .

[7]  A. Melis,et al.  Photochemical Apparatus Organization in Anacystis nidulans (Cyanophyceae) : Effect of CO(2) Concentration during Cell Growth. , 1984, Plant physiology.

[8]  M. Mimuro,et al.  Quantitative relationship between two reaction centersin the photosynthetic system of blue-green algae , 1979 .

[9]  H. K. Schachman,et al.  Characterization of cyanobacterial phycobilisomes in zwitterionic detergents. , 1979, Proceedings of the National Academy of Sciences of the United States of America.

[10]  E. Gantt.  Structure and Function of Phycobilisomes: Light Harvesting Pigment Complexes in Red and Blue-Green Algae , 1980 .

[11]  G. Offner,et al.  Primary structure of phycocyanin from the unicellular rhodophyte Cyanidium caldarium. II. Complete amino acid sequence of the beta subunit. , 1981, The Journal of biological chemistry.

[12]  Mihoko Yamamoto,et al.  C-phycocyanin from a red alga, Porphyra tenera: subunit structure , 1985 .

[13]  Siegelman Hw,et al.  Molecular morphology of cyanobacterial phycobilisomes , 1982 .

[14]  H. Zuber,et al.  Isolation and characterization of allophycocyanin II from the thermophilic blue‐green alga Mastigocladus laminosus cohn , 1974, FEBS letters.