Showing papers by "Alexander N. Glazer published in 1981"
TL;DR: The 75-, 33-, 30-, and 27-kilodalton polypeptide components of the phycobilisome of the unicellular cyanobacterium Synechococcus 6301 have been purified and characterized and peptide mapping shows that they are not related to each other by proteolytic processing.
142 citations
TL;DR: The above data indicate that the 75,000-dalton polypeptide functions as a terminal energy acceptor in the phycobilisome.
Abstract: A rapid procedure is described for the isolation of "linker" polypeptides (Lundell, D. J., R. C. Williams, and A. N. Glazer. 1981. J. Biol. Chem. 256:3580-3592) of cyanobacterial phycobilisomes. The 75,000-dalton component of the core of Synechococcus 6301 phycobilisomes isolated by this procedure has been shown to carry a bilin similar in spectroscopic properties to phycocyanobilin. "Renatured" 75,000-dalton polypeptide has absorption maxima at 610 and 665 nm and a fluorescence emission maximum at 676 nm, similar to that of intact phycobilisomes. A complex of allophycocyanin and a 40,000-dalton bilin-carrying fragment of the 75,000-dalton polypeptide, obtained by limited tryptic digestion, is described. This complex, which lacks allophycocyanin B, shows a fluorescence emission maximum at 676 nm. The above data indicate that the 75,000-dalton polypeptide functions as a terminal energy acceptor in the phycobilisome.
93 citations
TL;DR: Data on the physical, immunological and spectroscopic properties of Callithamnion phycoerythrins indicate that the variation in the relative number of the two bilin prosthetic groups does not affect significantly the conformation of the biliprotein.
Abstract: Phycoerythrins of several species of the higher red alga Callithamnion show virtually identical spectra, typical of R-phycoerythrins, with absorption maxima at 565, 539, and 497 nanometers. One species, Callithamnion roseum, produces a phycoerythrin lacking the peak at 539 nanometers. Comparison of a "typical" R-phycoerythrin from Callithamnion byssoides with the "atypical" phycoerythrin of C. roseum shows that both proteins carry 35 bilins per native molecule of 240,000 daltons; however, C. byssoides phycoerythrin carries 27.6 phycoerythrobilin and 7.3 phycourobilin groups, whereas C. roseum phycoerythrin carries 24.1 phycoerythrobilin and 10.9 phycourobilin groups. These differences in the relative amounts of the bilin prosthetic groups account in large measure for the differences between the absorption spectra of the native proteins. The ratio of phycoerythrobilin to phycourobilin in C. roseum phycoerythrin can be modulated by varying the light intensity during growth.Data on the physical, immunological and spectroscopic properties of Callithamnion phycoerythrins indicate that the variation in the relative number of the two bilin prosthetic groups does not affect significantly the conformation of the biliprotein.
73 citations
TL;DR: Results indicate that modulation of phycobilisome size involves concurrent regulation of the levels ofphycocyanin and of both the 30 and 33 kdalton polypeptides with no change in the composition of the allophycOCyanin-containing core.
Abstract: Phycobilisomes of the cyanobacterium Synechococcus 6301 contain the phycobiliproteins phycocyanin, allophycocyanin, and allophycocyanin B, and four major non pigmented polypeptides of 75, 33, 30, and 27 kdaltons. The molar ratio of phycocyanin to allophycocyanin in wild type phycobilisomes can be varied over about a two-fold range by alterations in culture conditions with parallel changes in the amounts of the 33 and 30 kdalton polypeptides whereas the levels of the 27 and 75 kdalton polypeptides do not vary. Two nitrosoguanidine-induced mutants, AN112 and AN135, produce abnormally small phycobilisomes, containing only 35 and 50% of the wild type level of phycocyanin. AN135 phycobilisomes contain less 33 kdalton polypeptide than wild type and the 30 kdalton polypeptide is only detected in phycobilisomes from cultures grown under conditions favoring high levels of phycocyanin. AN112 lacks both the 30 and 33 kdalton polypeptides and produces phycobilisomes of constant size and composition, independent of growth conditions. Both mutant phycobilisomes have wild type levels of 27 and 75 kdalton polypeptides relative to allophycocyanin and have normal energy transfer properties. These results indicate that modulation of phycobilisome size involves concurrent regulation of the levels of phycocyanin and of both the 30 and 33 kdalton polypeptides with no change in the composition of the allophycocyanin-containing core.
68 citations
TL;DR: These phycoerythrins are the first cyanobacterial phycobiliproteins found to carry aPhycourobilin prosthetic group, and may represent incompletely dissociated substructures of the phYcobilisome.
Abstract: The biliproteins of the unicellular, thylakoid-less cyanobacterium Gleobacter violaceus were resolved by chromatography on hydroxylapatite and DEAE-cellulose into five components: phycoerythrin I and II, phycocyanin I and II, and allophycocyanin. Allophycocyanin B was not detected. Three of these components, phycoerythrin II, phycocyanin II, and allophycocyanin, were purified to homogeneity. Phycoerythrin II crystallized as hexagonal prisms. G. violaceus allophycocyanin crystallized as thin plates; unter similar conditions other cyanobacterial allophycocyanins crystallize as needles. The biliproteins in the phycoerythrin I and phycocyanin I components were present in polydisperse, high molecular weight aggregates, which may represent incompletely dissociated substructures of the phycobilisome. Both phycoerythrin components from G. violaceus carry phycoerythrobilin and phycourbilin groups in the ratio of 6:1. Separation of the α and β subunits of these biliproteins revealed that the phycoerythrobilins were equally distributed between the two subunits, and that the β subunit alone carried the phycourobilin. These phycoerythrins are the first cyanobacterial phycobiliproteins found to carry a phycourobilin prosthetic group.
57 citations
TL;DR: Ten sexually reproducing strains of Callithamnion have been used in a comparison of phycoerythrin, interfertility and morphology and all cultures showed very similar mobilities in SDS gels.
Abstract: Ten sexually reproducing strains of Callithamnion have been used in a comparison of phycoerythrin, interfertility and morphology. Four isolates of C. byssoides Harvey from North America (Massachusetts, New York, North Carolina and Georgia) are all interfertile and they also hybridize with C. halliae Collins (UTEX LB1411) from Texas. Norwegian C. byssoides and C. roseum (Roth) Lyngbye (sensu Harvey) isolates are not interfertile with any North American strain. Phycoerythrins were compared by absorption spectroscopy, SDS gel electrophoresis and Ouchterlony double diffusion techniques. The absorption spectrum of phycoerythrin from the Massachusetts C. roseum is different from that of the R-phycoerythrin typical of all other strains. The subunits of phycoerythrin from all cultures showed very similar mobilities in SDS gels. Phycoerythrin from all C. byssoides and C. halliae reacted identically in Ouchterlony plates. Antigenic identity with C. byssoides was also seen with one strain (an unidentified species fr...
13 citations