The structural and functional alterations within the PSⅡ membrane from phosphatidylcholine reconstitution and Triton X-100 (TX-100) treatment were studied by using Fourier transform-infrared (FT-IR) spectroscopic technique and oxygen electrode. Phosphatidylcholine reconstitution showed no significant effect on the protein secondary structures of PSⅡ membrane but an increase of the rate of PSⅡ-mediated oxygen-evolution. The phosphatidylcholine lipids with different length of acyl chains displayed different capabilities to stimulate oxygen-evolution. In contrast, perturbation of the bilayer lipids by TX-100 resulted in obvious changes of the protein secondary structures within the PSⅡ membrane and in the loss of the PSⅡ-mediated oxygen-evolving activity. The results indicate the importance of membrane integrity in maintaining the stability of the photosynthetic membrane proteins.
磷脂酰胆碱和Triton X-100对光系统II蛋白二级结构及放氧活性影响的比较
阮翔1 许强1 毛海滨1 单际修2 公衍道1 张秀芳1 匡廷云2 赵南明1*
（1. 清华大学生物科学与技术系生物膜与膜生物工程国家重点实验室，北京100084；
2. 中国科学院植物研究所光合作用基础研究开放实验室，北京100093）
摘要：采用傅立叶变换红外光谱技术 (FT-IR)和氧电极研究了磷脂酰胆碱和TritonX-10 0对光系统Ⅱ膜复合物的蛋白二级结构及放氧活性的影响。结果表明 ,磷脂酰胆碱对光系统Ⅱ膜复合物的蛋白二级结构没有显著的影响 ,但能引起放氧活性的提高 ,而且脂酰侧链长度不同 ,对放氧活性的促进程度也不一样。相比较而言 ,TX-10 0对膜脂的扰动却引起蛋白二级结构的明显改变 ,并能抑致放氧活性。结果说明 ,完整的膜结构对维持光合膜蛋白的稳定是非常重要的。
关键词： 光系统II；磷脂酰胆碱；Triton X-100；FT-IR；放氧活性
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