紫球藻（Gloeobacter violaceus）PCC 7421中光系统I的次级电子受体是甲基萘醌-4，它通过一条独特但未知的途径合成。

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

作者信息

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

机构信息

Department of Technology and Ecology, Hall of Global Environmental Research, Kyoto University, Kyoto 606-8501, Japan.

出版信息

FEBS Lett. 2005 Jul 4;579(17):3493-6. doi: 10.1016/j.febslet.2005.05.029.

DOI:10.1016/j.febslet.2005.05.029

PMID:15955532

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.

摘要

通过将高效液相色谱图和吸收光谱与纯品化合物进行比较，确定了蓝细菌紫球藻PCC 7421中光系统（PS）I的次级电子受体为甲基萘醌-4（MQ-4）。据估计，MQ-4的含量为每一个P700的组成成分叶绿素（Chl）a'分子对应两个分子。比较基因组分析表明，紫球藻基因组中缺少八个编码叶绿醌/MQ生物合成酶的men基因中的六个。由于紫球藻能够明确合成MQ-4，综合结果表明，这种蓝细菌必定具有一条合成1,4-二羟基-2-萘甲酸的新途径。