Saga Yoshitaka, Yoshida Nozomi, Yamada Shota, Mizoguchi Tadashi, Tamiaki Hitoshi
Department of Chemistry, Faculty of Science and Engineering, Kindai University, Higashi-Osaka, Osaka 577-8502, Japan.
PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan.
Biochem Biophys Rep. 2016 Nov 19;9:42-46. doi: 10.1016/j.bbrep.2016.11.007. eCollection 2017 Mar.
Unnatural glycolipids possessing the diyne moiety in their acyl groups were successfully biosynthesized in the green sulfur photosynthetic bacterium (.) by cultivation with supplementation of 10,12-heptadecadiynic acid. Monogalactosyldiacylglycerol (MGDG) and rhamnosylgalactosyldiacylglycerol (RGDG) esterified with one 10,12-heptadecadiynic acid were primarily formed in the cells, and small amounts of glycolipids esterified with the two unnatural fatty acids can also be detected. The relative ratio of these unnatural glycolipids occupied in the total glycolipids was estimated to be 49% based on HPLC analysis using a evaporative light scattering detector. These results indicate that the acyl groups in glycolipids, which play important roles in the formation of extramembranous antenna complexes called chlorosomes, can be modified by cultivation of green sulfur photosynthetic bacteria with exogenous synthetic fatty acids. Visible absorption and circular dichroism spectra of containing the unnatural glycolipids demonstrated the formation of chlorosomes, indicating that the unnatural glycolipids in this study did not interfere with the biogenesis of chlorosomes.
通过添加10,12-十七碳二炔酸进行培养，在绿色硫光合细菌（.）中成功生物合成了在其酰基中含有二炔部分的非天然糖脂。细胞中主要形成了用一个10,12-十七碳二炔酸酯化的单半乳糖基二酰基甘油（MGDG）和鼠李糖基半乳糖基二酰基甘油（RGDG），并且还能检测到少量用两种非天然脂肪酸酯化的糖脂。基于使用蒸发光散射检测器的HPLC分析，这些非天然糖脂在总糖脂中所占的相对比例估计为49%。这些结果表明，在称为叶绿体的膜外天线复合物形成中起重要作用的糖脂中的酰基，可以通过用外源合成脂肪酸培养绿色硫光合细菌来进行修饰。含有非天然糖脂的（.）的可见吸收光谱和圆二色光谱表明形成了叶绿体，这表明本研究中的非天然糖脂不干扰叶绿体的生物合成。
