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Characterization of the quinones in purple sulfur bacterium Thermochromatium tepidum
Author(s) -
Kimura Yuuka,
Kawakami Tomoaki,
Yu Long-Jiang,
Yoshimura Miku,
Kobayashi Masayuki,
Wang-Otomo Zheng-Yu
Publication year - 2015
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2015.05.043
Subject(s) - sulfur , bacteria , chemistry , biochemistry , microbiology and biotechnology , biology , organic chemistry , genetics
Quinone distributions in the thermophilic purple sulfur bacterium Thermochromatium tepidum have been investigated at different levels of the photosynthetic apparatus. Here we show that, on average, the intracytoplasmic membrane contains 18 ubiquinones (UQ) and 4 menaquinones (MQ) per reaction center (RC). About one‐third of the quinones are retained in the light‐harvesting–reaction center core complex (LH1–RC) with a similar ratio of UQ to MQ. The numbers of quinones essentially remains unchanged during crystallization of the LH1–RC. There are 1–2 UQ and 1 MQ associated with the RC‐only complex in the purified solution sample. Our results suggest that a large proportion of the quinones are confined to the core complex and at least five UQs remain invisible in the current LH1–RC crystal structure.