The secondary electron acceptor of photosystem I in Gloeobacter violaceus PCC 7421 is menaquinone-4 that is synthesized by a unique but unknown pathway

Mimuro, Mamoru; Tsuchiya, Tohru; Inoue, Hidetoshi; Sakuragi, Yumiko; Itoh, Yuka; Gotoh, Takanori; Miyashita, Hideaki; Bryant, Donald A.; Kobayashi, Masami

doi:10.1016/j.febslet.2005.05.029

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Volume 579, Issue 17 , Pages 3493-3496, 4 July 2005

The secondary electron acceptor of photosystem I in Gloeobacter violaceus PCC 7421 is menaquinone-4 that is synthesized by a unique but unknown pathway

Edited by Richard Cogdell

Mamoru Mimuro
- Department of Technology and Ecology, Hall of Global Environmental Research, Kyoto University, Kyoto 606-8501, Japan
- Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501, Japan
- Corresponding author. Fax: +81 75 753 6855.
Tohru Tsuchiya
- Department of Technology and Ecology, Hall of Global Environmental Research, Kyoto University, Kyoto 606-8501, Japan
- Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501, Japan
Hidetoshi Inoue
- Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501, Japan
Yumiko Sakuragi
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
- Present address: Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA.
Yuka Itoh
- Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan
Takanori Gotoh
- Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan
Hideaki Miyashita
- Department of Technology and Ecology, Hall of Global Environmental Research, Kyoto University, Kyoto 606-8501, Japan
- Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501, Japan
Donald A. Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
Masami Kobayashi
- Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan

Received 22 April 2005; accepted 11 May 2005. published online 03 June 2005.

Abstract

The secondary electron acceptor of photosystem (PS) I in the cyanobacterium Gloeobacter violaceus PCC 7421 was identified as menaquinone-4 (MQ-4) by comparing high performance liquid chromatograms and absorption spectra with an authentic compound. The MQ-4 content was estimated to be two molecules per one molecule of chlorophyll (Chl) a′, a constituent of P700. Comparative genomic analyses showed that six of eight men genes, encoding phylloquinone/MQ biosynthetic enzymes, are missing from the G. violaceus genome. Since G. violaceus clearly synthesizes MQ-4, the combined results indicate that this cyanobacterium must have a novel pathway for the synthesis of 1,4-dihydroxy-2-naphthoic acid.

Abbreviations: Chl, chlorophyll, DHNA, 1,4-dihydroxy-2-naphthoic acid, HPLC, high performance liquid chromatography, MQ, menaquinone, P700, the primary electron donor of photosystem I, PhQ, phylloquinone, PQ, plastoquinone, PS, photosystem