Open AccessSingle core polypeptide in the reaction center of the photosynthetic bacterium Heliobacillus mobilis: structural implications and relations to other photosystems.
Author(s) -
Ursula Liebl,
Melissa Mockensturm-Wilson,
Jeffrey T. Trost,
Daniel C. Brune,
Robert E. Blankenship,
Wim F. J. Vermaas
Publication year - 1993
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.90.15.7124
Subject(s) - photosynthetic reaction centre , anoxygenic photosynthesis , photosystem , purple bacteria , peptide sequence , biology , green sulfur bacteria , photosystem i , chlorosome , chemistry , photosystem ii , bacteriochlorophyll , photosynthesis , stereochemistry , biochemistry , gene , phototroph
The gene for a reaction center core polypeptide from the anoxygenic photosynthetic bacterium Heliobacillus mobilis was cloned and sequenced. The deduced amino acid sequence consists of 609 residues with a molecular mass of 68 kDa. An adjacent open reading frame is not transcribed under our experimental conditions. No evidence for a second related reaction center core gene was found. The primary sequence of the reaction center protein (P800 protein) shows a high percentage of sequence identity to photosystem I in a cysteine-containing loop, which is the putative binding site of the iron-sulfur center FX and in the preceding hydrophobic region. Our data imply a homodimeric organization of the reaction center. This is fundamentally different from photosystem I and most other photosynthetic reaction centers, where the reaction center core is composed of two similar but nonidentical subunits.