Single core polypeptide in the reaction center of the photosynthetic bacterium Heliobacillus mobilis: Structural implications and relations to other photosystems

Ursula Liebl, Melissa Mockensturm-Wilson, Jeffrey T. Trost, Daniel C. Brune, Robert E. Blankenship, Willem Vermaas

Research output: Contribution to journalArticle

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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.

Original languageEnglish (US)
Pages (from-to)7124-7128
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume90
Issue number15
Publication statusPublished - Aug 1 1993

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Keywords

  • Evolution
  • Heliobacteria
  • Photosynthesis
  • Photosystem I

ASJC Scopus subject areas

  • General
  • Genetics

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