The complete amino acid sequences of the b 800—850 antenna polypeptides from rhodopseudomonas acidophila strain 7750

• Published in: Zeitschrift für Naturforschung C. A journal of biosciences Vol. 43; no. 1; pp. 77 - 83
• Main Authors: Bissig, Iwan, Brunisholz, René A., Suter, Franz, Cogdell, Richard J., Zuber, Herbert
• Format: Journal Article
• Language: English
• Published: Verlag der Zeitschrift für Naturforschung 01-02-1988
• Subjects: Amino Acid Sequence; B800-850 Antenna Complex; Light-Harvesting Polypeptide; Purple Nonsulfur Bacterium; Rhodopseudomonas acidophila
• ISSN: 0939-5075; 1865-7125
• DOI: 10.1515/znc-1988-1-216

Spectrally pure B 800-850 light harvesting complexes of Rhodopseudomonas acidophila 7750 were prepared by chromatography of LDAO-solubilised photosynthetic membranes on Whatmann DE-52 ion exchange resin. Two low molecular mass polypeptides (α, β) have been isolated by organic solvent extraction of the lyophilised B 800-850 light harvesting complexes. Their primary structures were determined by liquid phase sequencer runs, by the sequence analyses of C-terminal o-iodosobenzoic acid fragments, by hydrazinolysis and by carboxypeptidase degradation.
B 800-850-a consists of 53 amino acids and is 45.3% and 50.9% homologous to the B 800-850- a antenna polypeptides of Rhodobacter sphaeroides and Rhodobacter capsulatus, respectively. The second very short polypeptide (B800-850-β, 41 amino acids) is 61.0% and 56.1% homologous to the corresponding polypeptides of Rb. sphaeroides and Rb. capsulatus. The molar ratio of the two polypeptides is about 1:1. Both polypeptides show a hydrophilic N-terminal domain, a very hydrophobic central domain and a short C-terminal domain. In both polypeptides the typical His residues, identified in all antenna polypeptides of purple nonsulphur bacteria as possible bacteriochlorophyll binding sites, were found