Partial purification, subunit structure and thermal stability of the photochemical reaction center of the thermophilic green bacterium Chloroflexus aurantiacus

Beverly K. Pierson*, J. Philip Thornber, Richard E.B. Seftor

*Corresponding author for this work

Research output: Contribution to journalArticle

45 Scopus citations

Abstract

Spectrally pure reaction center preparations from Chloroflexus aurantiacus have been obtained in a stable form; however, the product contained several contaminating polypeptides. The reaction center pigment molecules (probably three bacteriochlorophyll a and three bacteriopheophytin a molecules) are associated with two polypeptides (Mr = 30000 and 28000) in a reaction center complex of Mr = 52000. No carotenoid is present in the complex. These data together with previous spectral data suggest that the Chloroflexus reaction center represents a more primitive evolutionary form of the purple bacterial reaction center, and that it has little if any relationship to the green bacterial component. A reaction center preparation from Rhodopseudomonas sphaeroides R26 was fully denatured at 50°C while the Chloroflexus reaction center required higher temperatures (70-75°C) for complete denaturation. Thus, an intrinsic membrane protein of a photosynthetic thermophile has been demonstrated to have greater thermal stability than the equivalent component of a mesophile.

Original languageEnglish (US)
Pages (from-to)322-326
Number of pages5
JournalBBA - Bioenergetics
Volume723
Issue number2
DOIs
StatePublished - May 27 1983

Keywords

  • (Chloroflexus aurantiacus)
  • Bacterial photosynthesis
  • Chlorophyll-protein complex
  • Reaction center
  • Thermal stability
  • Thermophilic bacterium

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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