Parallel electron donation pathways to cytochrome cz in the type I homodimeric photosynthetic reaction center complex of Chlorobium tepidum

Yusuke Tsukatani, Chihiro Azai, Toru Kondo, Shigeru Itoh, Hirozo Oh-oka

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)

Abstract

We studied the regulation mechanism of electron donations from menaquinol:cytochrome c oxidoreductase and cytochrome c-554 to the type I homodimeric photosynthetic reaction center complex of the green sulfur bacterium Chlorobium tepidum. We measured flash-induced absorption changes of multiple cytochromes in the membranes prepared from a mutant devoid of cytochrome c-554 or in the reconstituted membranes by exogenously adding cytochrome c-555 purified from Chlorobium limicola. The results indicated that the photo-oxidized cytochrome cz bound to the reaction center was rereduced rapidly by cytochrome c-555 as well as by the menaquinol:cytochrome c oxidoreductase and that cytochrome c-555 did not function as a shuttle-like electron carrier between the menaquinol:cytochrome c oxidoreductase and cytochrome cz. It was also shown that the rereduction rate of cytochrome cz by cytochrome c-555 was as high as that by the menaquinol:cytochrome c oxidoreductase. The two electron-transfer pathways linked to sulfur metabolisms seem to function independently to donate electrons to the reaction center.

Original languageEnglish
Pages (from-to)1211-1217
Number of pages7
JournalBiochimica et Biophysica Acta - Bioenergetics
Volume1777
Issue number9
DOIs
Publication statusPublished - 2008 Sep
Externally publishedYes

Keywords

  • Cytochrome c
  • Cytochrome c-554
  • Green sulfur bacteria
  • Menaquinol:cytochrome c oxidoreductase
  • Reaction center
  • Sulfur oxidation

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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