Abstract
Green sulfur bacteria are obligatory anaerobic photo-autotrophic organisms. They have many unique and intriguing features in their photosynthetic system. For example, their reaction center (RC) complexes consist of homodimeric core protein, and inorganic carbon assimilation pathway is not common Calvin cycle but reductive TCA cycle. Since their strictly anaerobic properties make it difficult to conduct various biochemical studies, molecular genetic analysis is the most promising approach to understand their photosynthesis at a molecular level. In Chlorobaculum tepidum, the complete genome sequence and the transformation system based on homologous recombination was available. Although many knock-out mutants have revealed the functions of various genes so far, the genes that are essential for photosynthetic growth have barely been investigated because of the photoautotrophy of green sulfur bacteria. Therefore, it has been required for further investigations to develop a gene expression system enabling complementation analyses. In this study, we constructed the exogenous gene expression vector using a broad-host-range plasmid.
