Phycoerythrins of marine unicellular cyanobacteria. I. Bilin types and locations and energy transfer pathways in Synechococcus spp. phycoerythrins

• Published in: The Journal of biological chemistry 1991-05, Vol.266 (15), p.9515-9527
• Main Authors: ONG, L. J, GLAZER, A. N
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Analytical, structural and metabolic biochemistry; Bile Pigments - metabolism; Biological and medical sciences; Chromatography, High Pressure Liquid; Cyanobacteria - metabolism; cyanophyta; energia; energie; energy; Energy Transfer; Fundamental and applied biological sciences. Psychology; Heterocyclic compounds, pigments; light; lumiere; luz; Molecular Sequence Data; Other biological molecules; Peptide Mapping; Phycobilisomes; Phycoerythrin - metabolism; pigment; pigmentos; pigments; proteinas; proteine; proteins; Sequence Homology, Nucleic Acid; Tetrapyrrolic pigments; Trypsin
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/s0021-9258(18)92851-6

Marine Synechococcus strains WH8103, WH8020, and WH7803 each possess two different phycoerythrins, PE(II) and PE(I), in a weight ratio of 2-4:1. PE(II) and PE(I) differ in amino acid sequence and in bilin composition and content. Studies with strain WH7803 indicated that both PE(II) and PE(I) were present in the same phycobilisome rod substructures and that energy absorbed by PE(II) was transferred to PE(I). Strain WH8103 and WH8020 PE(I)s carried five bilin chromophores thioether-linked to cysteine residues in sequences homologous to those previously characterized in C-, B-, and R-PEs. In contrast, six bilins were attached to strain WH8103 and WH8020 PE(II)s. Five of these were at positions homologous to bilin attachment sites in other phycoerythrins. The additional bilin attachment site was on the alpha subunit. The locations and bilin types in these PE(s) and in the marine Synechocystis strain WH8501 PE(I) (Swanson, R.V., Ong, L.J., Wilbanks, S.M., and Glazer, A.N. (1991) J. Biol. Chem. 266, 9528-9534) are: (...). Since phycourobilin (PUB) (lambda(max) approximately 495 nm) transfers energy to phycoerythrobilin (PEB) (lambda(max) approximately nm), inspection of these data shows that the invariant PEB group at beta-82 is the terminal energy acceptor in phycoerythrins. The adaptations to blue-green light, high PUB content and the presence of an additional bilin on the alpha subunit, increase the efficiency of light absorption by PE(II)s at approximately 500 nm.