ISSN:
1432-072X
Keywords:
Phycobiliprotein (λ 671, 618 nm)
;
Allophycocyanin B
;
Photosystem II
;
Cyanobacteria
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract A hitherto undescribed red fluorescent phycobiliprotein (maximum emission at ∼ 680 nm), characterized by long wavelength absorption maxima in the visible region at 671 nm (ε=172000 M−1·cm−1 per monomer of mol. wt. 30600) and 618 nm, has been purified to homogeneity from a unicellular cyanobacterium, Synechococcus sp., and from a filamentous cyanobacterium, Anabaena variabilis. The name allophycocyanin B has been proposed for the new protein. A. variabilis allophycocyanin B is characterized by a native molecular weight of 89000 ± 5000 (in 0.05 M phosphate at pH 7.2), an isoelectric point of 5.09, and a subunit molecular weight, based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, of 15300. The protein contains one phycocyanobilin chromophore per subunit. In common with allophycocyanin from the same organism, allophycocyanin B does not contain either histidine or tryptophan. In other respects, the amino acid compositions of the two proteins are significantly different. Synechococcus sp. (Anacystis nidulans) allophycocyanin B gives two components of 16000 and 17000 mol. wt., of equal staining intensity, on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Allophycocyanins B from both organisms cross-react with rabbit antisera directed against either Synechococcus sp. or Anabaena sp. allophycocyanin, but not with antisera against the phycocyanins of the same organisms. It is suggested that allophycocyanin B occupies a position between allophycocyanin and chlorophyll a in the energy transfer path from the accessory pigments to species of chlorophyll a with absorption maxima at λ〉670 nm.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00447294
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