Functional analysis of quinone in the photosynthetic reaction center complex of green sulfur bacteria

2014 Fiscal Year Final Research Report

• Project/Area Number: 25891025
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Single-year Grants
• Research Field: Biophysics
• Research Institution: Ritsumeikan University
• Principal Investigator: AZAI Chihiro 立命館大学, 生命科学部, 助教 (70706564)
• Project Period (FY): 2013-08-30 – 2015-03-31
• Keywords: 光合成反応中心 / 緑色硫黄細菌 / 広宿主域プラスミド / Hisタグ / 電子移動 / 過渡吸収 / キノン

Outline of Final Research Achievements

A gene expression system by a broad host range plasmid was established in the green sulfur bacterium Chlorobaculum tepidum, which is a strictly anaerobic photosynthetic bacterium. Large-scale preparation of the homodimeric photosynthetic reaction center (RC) complex of green sulfur bacteria was easily achieved by over-expression of the His-tagged RC core-protein and its affinity purification.
Electron transfer reactions in the green sulfur bacterial RC complex were observed by transient absorption spectroscopy from sub-nanosecond to millisecond time domains. The electron transfer pathway was affected by additives in the reaction solution; it was suggested that there is an unidentified cofactor serving as an alternate terminal electron acceptor of the normal iron-sulfur cluster in the green sulfur bacterial RC complex.

Free Research Field

生物物理学