Merkel, Joseph R. (College of Charleston, Charleston, S.C.), Gordon D. Braithwaite, and Henry Kritzler. Proteolytic attack of the chromoproteins of Porphyra by marine bacterial enzymes. J. Bacteriol. 88:974-980. 1964.-Three chromoproteins were isolated from the marine red alga, Porphyra leucosticta (Thuret), and were purified by adsorption chromatography on calcium phosphate gel and by ammonium...

A procedure was developed for the isolation of phycobilisomes from Porphyridium cruentum. The cell homogenate, suspended in phosphate buffer (pH 6.8), was treated with 1% Triton X-100, and its supernatant fraction was centrifuged on a sucrose step gradient. Phycobilisomes were recovered in the 1 M sucrose band. The phycobilisome fraction was identified by the characteristic appearance of the ph...

Ramachandran calculations have been used to gain insight into steric hindrance in bile pigments related to biliprotein chromophores. The high optical activity of denatured phycocyanin, as compared to phycoerythrin, has been related to the asymmetric substitution at ring A, which shifts the equilibrium towards the P-helical form of the chromophore. Geometric effects on the electronic structures ...

Phycobilisomes were prepared from a marine red macroalga Polysiphonia urceolata (P. urceolata) by sucrose step-gradient ultracentrifugation. From the prepared phycobilisomes, an R-phycocyanin was isolated by gel filtration on Sephadex G-150 and then purified by ion exchange chromatography on DEAE-Sepharose Fast Flow and native polyacrylamide gel electrophoresis (PAGE) performed in neutral buffe...

Single crystal x-ray diffraction studies are proceeding on two phycobiliproteins: C-Phycocyanin from Anabaena variabilis and B-Phycoerythrin from Porphyridium cruentum. C-Phycocyanin consists of six alpha and six beta subunits. A three-dimensional x-ray diffraction study of this light-harvesting protein (P6(3); a = b = 154.1 A, c = 40.1 A) at 5-A resolution shows that the molecule is 110 A in d...

The recent availability of the whole genome of Synechococcus sp. strain WH8102 allows us to have a global view of the complex structure of the phycobilisomes of this marine picocyanobacterium. Genomic analyses revealed several new characteristics of these phycobilisomes, consisting of an allophycocyanin core and rods made of one type of phycocyanin and two types of phycoerythrins (I and II). Al...

Ultraviolet (UV)-absorbing mycosporine-like amino acids (MAAs) were separated from a marine red alga Gracilaria cornea using HPLC. The isolated MAAs were identified as porphyra-334 and/or shinorine by comparing them with various standards. No in vivo induction of MAAs was detected in G. cornea even when the organism was grown for 4–5 days either in the presence of UV-A and UV-B only or in combi...

Addition of millimolar concentrations of glyoxylate to nitrogen-fixing cultures of Anabaena cylindrica, grown aerobically in the light, caused the following effects: an increase in the number of glycogen granules and in the excretion of carbohydrates; a decreased phycocyanin concentration, but an increase in the chlorophyll a to phycocyanin ratio. Also, an enhancement in the carbon to nitrogen ...

Phycobiliproteins are water-soluble, light-harvesting proteins that are highly fluorescent due to linear tetrapyrrole chromophores, which makes them valuable as probes. Enzymes called bilin lyases usually attach these bilin chromophores to specific cysteine residues within the alpha and beta subunits via thioether linkages. A multiplasmid coexpression system was used to recreate the biosyntheti...

Phycobilisomes were prepared from a marine red macroalga Polysiphonia urceolata (P. urceolata) by sucrose step-gradient ultracentrifugation. From the prepared phycobilisomes, an R-phycocyanin was isolated by gel filtration on Sephadex G-150 and then purified by ion exchange chromatography on DEAE-Sepharose Fast Flow and native polyacrylamide gel electrophoresis (PAGE) performed in neutral buffe...