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C-type cytochromes in the photosynthetic electron transfer pathways in green sulfur bacteria and heliobacteria

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Abstract

Green sulfur bacteria and heliobacteria are strictly anaerobic phototrophs that have homodimeric type 1 reaction center complexes. Within these complexes, highly reducing substances are produced through an initial charge separation followed by electron transfer reactions driven by light energy absorption. In order to attain efficient energy conversion, it is important for the photooxidized reaction center to be rapidly rereduced. Green sulfur bacteria utilize reduced inorganic sulfur compounds (sulfide, thiosulfate, and/or sulfur) as electron sources for their anoxygenic photosynthetic growth. Membrane-bound and soluble cytochromes c play essential roles in the supply of electrons from sulfur oxidation pathways to the P840 reaction center. In the case of gram-positive heliobacteria, the photooxidized P800 reaction center is rereduced by cytochrome c-553 (PetJ) whose N-terminal cysteine residue is modified with fatty acid chains anchored to the cytoplasmic membrane.

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Abbreviations

Bchl:

Bacteriochlorophyll

Cyt:

Cytochrome

ET:

Electron transfer

FAP:

Filamentous anoxygenic phototroph

P840:

Primary electron donor made of a special pair of bacteriochlorophylls a in the green sulfur bacterial RC

P800:

Primary electron donor made of a special pair of bacteriochlorophylls g in the heliobacterial RC

PS I:

Photosystem I

PS II:

Photosystem II

RC:

Reaction center

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Acknowledgments

This study was financially supported by Grants-in-Aid for Scientific Research (C) (No. 21570168) (to H.O.) from the Ministry of Education, Culture, Sports, Science, and Technology of Japan and by postdoctoral fellowships from the Japan Society for the Promotion of Science (No. 211578 to C.A, No. 181481 to Y.T.).

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Authors and Affiliations

  1. Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan

    Chihiro Azai & Hirozo Oh-oka

  2. Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA

    Yusuke Tsukatani

  3. Division of Material Science (Physics), Graduate School of Science, Nagoya University, Nagoya, 464-8602, Japan

    Shigeru Itoh

Authors
  1. Chihiro Azai
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  2. Yusuke Tsukatani
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  3. Shigeru Itoh
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  4. Hirozo Oh-oka
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Correspondence to Hirozo Oh-oka.

Additional information

In this review, the old species names of green sulfur bacteria were transcribed to new ones according to Imhoff’s definition (Imhoff 2003).

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Azai, C., Tsukatani, Y., Itoh, S. et al. C-type cytochromes in the photosynthetic electron transfer pathways in green sulfur bacteria and heliobacteria. Photosynth Res 104, 189–199 (2010). https://doi.org/10.1007/s11120-009-9521-4

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