类囊体膜脂对菠菜来源光系统Ⅰ结构性质的影响

Influence of thylakoid lipids on structural properties of Photosystem Ⅰ from spinach

为研究类囊体膜脂对光系统I结构性质的影响,利用圆二色光谱仪、激光纳米粒度仪等现代分析手段,考察了4种类囊体膜脂MGDG、DGDG、SQDG和PG对菠菜来源光系统I吸收光谱、低温荧光光谱、热稳定性及耗氧活性等多种结构性质的影响。结果表明:带负电荷的膜脂(SQDG和PG)与电中性的膜脂(MGDG和DGDG)对光系统Ⅰ的吸收光谱、低温荧光光谱和热稳定性的影响存在不同。此外,4种类囊体膜脂的加入使得光系统I的耗氧活性显著提高,其在溶液中的聚集尺寸也明显增大。

In the present work,the influence of four thylakoid lipids,monogalactosyldiacylglycerol(MGDG),digalactosyldiacylglycerol(DGDG),sulfoquinovosyldiacylglycerol(SQDG)and phosphatidylglycerol(PG),on the properties of PhotosystemⅠ(PSⅠ)was investigated.After incubation with separate lipid,the properties of PSⅠincluding UV-vis absorption,low-temperature fluorescence,thermal stability,oxygen consumption activity and effective size in solution were determined.The effects of negatively charged lipids(SQDG and PG)and neutral lipids(MGDG and DGDG)on the properties of PhotosystemⅠwere different.The results also showed that the addition of four thylakoid lipids greatly increased the activity of PSⅠas well as the effective size in solution.