Selective photobleaching of chlorophylls and carotenoids in photosystem I particles under high-light treatment
Selective photobleaching of chlorophylls and carotenoids in photosystem I particles under high-light treatment
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DOI：
10.1111/j.1751-1097.2007.00136.x
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发表时间：
2007-11-01
影响因子：
3.3
通讯作者：
Velitchkova, Maya
中科院分区：
文献类型：
--
作者：
Andreeva, Atanaska;Abarova, Silvia;Velitchkova, Maya
利用吸收光谱、77 K荧光光谱和共振拉曼（RR）光谱研究了从菠菜叶片中分离的光系统I粒子（PSI-200）。目的是更好地了解在长时间暴露于强光强度的过程中，这些颗粒中的色素光谱特性的变化，并揭示这些色素参与PSI的光保护。在长时间暴露于高光强度的菠菜PSI颗粒，观察到大量的光合色素的损失。结果表明，不同色素对光损伤的敏感性不同。除了叶绿素a（Chla）的漂白之外，还清楚地观察到类胡萝卜素的漂白。RR技术使我们能够识别光漂白类胡萝卜素分子的类型和构象。拉曼数据揭示了一个几乎完全的长波长叶黄素分子的光漂白。叶黄素分子和最红移的长波长叶绿素a，位于天线膜蛋白Lhca 4，所观察到的类似的漂白率，表明这些分子位于密切。结果表明，光漂白的天线色素，特别是叶黄素和最长波长吸收叶绿素参与PSI核心复合物的光保护。
Photosystem I particles (PSI-200) isolated from spinach leaves were studied by means of absorbance, 77K fluorescence and resonance Raman (RR) spectroscopy. The aim was to obtain better insight into the changes of the pigment spectral properties in those particles during prolonged exposure to high-light intensities and to reveal the involvement of these pigments in the photoprotection of the PSI. During prolonged exposure to high-light intensities of spinach PSI particles, a loss of a significant amount of photosynthetic pigments was observed. It was shown that various pigments exhibited different susceptibility to photodamage. In addition to bleaching of chlorophyll a (Chl a), bleaching of carotenoids was also clearly observed. RR technique allowed us to recognize the type and conformation of photobleached carotenoid molecules. Raman data revealed a nearly full photobleaching of the long-wavelength lutein molecules. The observed similar bleaching rate of the lutein molecules and the most-red shifted long-wavelength Chl a, located in the antenna membrane protein Lhca4, suggested that these molecules are located closely. Our results showed that the photobleached antenna pigments and especially luteins and the most long-wavelength absorbing chlorophylls are involved in photoprotection of PSI core complex.