title: Single core polypeptide in the reaction center of the photosynthetic bacterium Heliobacillus mobilis: structural implications and relations to other photosystems.
abstract: 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.
authors.affiliation: Department of Botany, Arizona State University, Tempe 85287.
authors.forename: U
authors.initials: U
authors.lastname: Liebl
authors.forename: M
authors.initials: M
authors.lastname: Mockensturm-Wilson
authors.forename: J T
authors.initials: JT
authors.lastname: Trost
authors.forename: D C
authors.initials: DC
authors.lastname: Brune
authors.forename: R E
authors.initials: RE
authors.lastname: Blankenship
authors.forename: W
authors.initials: W
authors.lastname: Vermaas
mesh_terms: D000595:Amino Acid Sequence; D001419:Bacteria / Q000737:chemistry* / Q000235:genetics; D001483:Base Sequence; D003001:Cloning, Molecular; D015870:Gene Expression; D005798:Genes, Bacterial; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009876:Operon; D010788:Photosynthesis; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry / Q000235:genetics*; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics; D015183:Restriction Mapping; D016415:Sequence Alignment; D012995:Solubility; D014158:Transcription, Genetic
chemical_list: D046911:Macromolecular Substances; D045322:Photosynthetic Reaction Center Complex Proteins; D012333:RNA, Messenger