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A new possible binding site for bacteriochlorophyll b in a light‐harvesting polypeptide of the bacterium Ectothiorhodospira halochloris
Author(s) -
Wagner-Huber Regula,
Brunisholz René A.,
Bissig Iwan,
Frank Gerhard,
Zuber Herbert
Publication year - 1988
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(88)81345-0
Subject(s) - rhodospirillales , bacteria , bacteriochlorophyll , biochemistry , biology , histidine , purple bacteria , asparagine , peptide sequence , amino acid , residue (chemistry) , photosynthetic reaction centre , photosynthesis , gene , genetics
Whole cells from Ectothiorhodospira halochloris were extracted with an organic solvent mixture. At least five small hydrophobic polypeptides representing most probably the light harvesting polypeptides were purified by gel filtration and consecutive FPLC‐RP chromatography. The complete amino acid sequence of a 7.4 kDa polypeptide was determined. The polypeptide shows a three domain structure, indicative of an integral membrane protein, similar to the structure of the light‐harvesting polypeptides from purple non‐sulfur bacteria. Sequence homologies to the β‐LHPs of purple bacteria range from 23. 1° to 36.4°. The conserved intramembrane located histidine residue of the antenna polypeptides of purple non‐sulfur bacteria, assigned as the possible binding site for bacteriochlorophyll, was found to be replaced by asparagine.