Reversed-phase HPLC determination of chlorophyll a′ and phylloquinone in Photosystem I of oxygenic photosynthetic organisms -: Universal existence of one chlorophyll a′ molecule in Photosystem I
Reversed-phase HPLC determination of chlorophyll a′ and phylloquinone in Photosystem I of oxygenic photosynthetic organisms -: Universal existence of one chlorophyll a′ molecule in Photosystem I
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DOI：
10.1046/j.1432-1033.2003.03616.x
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发表时间：
2003-06-01
期刊：
影响因子：
--
通讯作者：
Watanabe, T
中科院分区：
文献类型：
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作者：
Nakamura, A;Akai, M;Watanabe, T
叶绿素（Chl）a '是Chl a的C13（2）-差向异构体，是高温蓝细菌细长聚球藻（Synechococcus elongatus）光系统（PS）I的初级电子供体（P700）的组成部分。为了确定光合产氧生物的PS I是否普遍含有一个Chla '分子，从蓝藻T.通过反相HPLC同时检测叶绿醌（PS I的次级电子受体）和Chl a'，对细长集胞藻（Synechocystissp. PCC 6803）、莱氏绿色衣藻（Chlamycellusreinhardtii）和绿色植物菠菜进行了检测。结果与Chl a/P700比值进行了比较。所有被测生物的类囊体膜和PS I的Chla '/PS I比值均约为1，在去除了大部分外围亚基后，PS I中仍有一个Chla'分子。叶绿素a'表现出一个特征提取行为显着不同的散装叶绿素a在丙酮/甲醇提取时，不同的混合比。这些结果证实了P700中单一的Chla '分子是以Chla为基础的产氧光合生物PS I的普遍特征。
Chlorophyll (Chl) a', the C13(2)-epimer of Chl a, is a constituent of the primary electron donor (P700) of Photosystem (PS) I of a thermophilic cyanobacterium Synechococcus (Thermosynechococcus) elongatus , as was recently demonstrated by X-ray crystallography. To determine whether PS I of oxygenic photosynthetic organisms universally contains one molecule of Chl a', pigment compositions of thylakoid membranes and PS I complexes isolated from the cyanobacteria T. elongatus and Synechocystis sp. PCC 6803, the green alga Chlamydomonas reinhardtii , and the green plant spinach, were examined by simultaneous detection of phylloquinone (the secondary electron acceptor of PS I) and Chl a' by reversed-phase HPLC. The results were compared with the Chl a/P700 ratio determined spectrophotometrically. The Chl a'/PS I ratios of thylakoid membranes and PS I were about 1 for all the organisms examined, and one Chl a' molecule was found in PS I even after most of the peripheral subunits were removed. Chl a' showed a characteristic extraction behaviour significantly different from the bulk Chl a in acetone/methanol extraction upon varying the mixing ratio. These findings confirm that a single Chl a' molecule in P700 is the universal feature of PS I of the Chl a-based oxygenic photosynthetic organisms.