CORE ANTENNA COMPLEXES, CP43 AND CP47, OF HIGHER-PLANT PHOTOSYSTEM-II - SPECTRAL PROPERTIES, PIGMENT STOICHIOMETRY, AND AMINO-ACID-COMPOSITION
CORE ANTENNA COMPLEXES, CP43 AND CP47, OF HIGHER-PLANT PHOTOSYSTEM-II - SPECTRAL PROPERTIES, PIGMENT STOICHIOMETRY, AND AMINO-ACID-COMPOSITION
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DOI：
10.1021/bi00200a034
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发表时间：
1994-08-30
期刊：
影响因子：
2.9
通讯作者：
PICOREL, R
中科院分区：
文献类型：
--
作者：
ALFONSO, M;MONTOYA, G;PICOREL, R
核心天线复合物的光系统II，CP 43和CP 47，纯化从两个高等植物通过阴离子交换色谱法，使用的离液剂LiClO 4和非离子洗涤剂β-十二烷基麦芽糖苷的组合。CP 43的Q（y）跃迁在48 K下分解为两个主带，分别位于682.3和671.5 nm附近，而CP 47的光谱显示出更复杂的结构，主带位于688、681.2、676、670、667和661 nm。发射带（77 K）分别在683和695 nm的CP 43和CP 47。荧光激发光谱显示叶绿素的不同跃迁之间的能量转移效率很高，而β-胡萝卜素的能量转移效率稍低。CP 47的圆二色性光谱表明，一些叶绿素之间存在激子相互作用。相比之下，CP 43在670 nm处显示单一负圆二色性带。通过光谱测量和HPLC确定复合物的色素含量。采用Lowry或Bradford的蛋白质定量方法，发现每个CP 43多肽含有18种叶绿素a和5种β-胡萝卜素，每个CP 47多肽含有19种叶绿素a和3种β-胡萝卜素。当从氨基酸分析确定蛋白质浓度时，每个CP 43获得20个叶绿素a和5个β-胡萝卜素，每个CP 47获得21-22个叶绿素a和4个β-胡萝卜素。因此，假定每个反应中心有4-6个叶绿素，则核心络合物的叶绿素a含量为4-6 -48，这与使用高纯度的放氧核心络合物实验获得的组成一致。这表明在纯化过程中没有色素损失。此外，纯化的复合物的氨基酸分析显示与来自其他高等植物的基因序列的氨基酸组成的高度同源性。
The core antenna complexes of photosystem II, CP43 and CP47, were purified from two higher plants by anion-exchange chromatography, using a combination of the chaotropic agent LiClO4 and the nonionic detergent beta-dodecyl maltoside. The Q(y) transition was resolved at 48 K into two main bands near 682.3 and 671.5 nm for CP43, while the CP47 spectrum showed a more complex structure with main bands at 688, 681.2, 676, 670, 667, and 661 nm. Emission bands (77 K) were detected at 683 and 695 nm for CP43 and CP47, respectively. Fluorescence excitation spectra showed high efficiency of energy transfer between the different transitions of the chlorophylls and a somewhat lower efficiency from beta-carotene. The circular dichroism spectrum of CP47 indicated the presence of excitonic interactions between some chlorophylls. In contrast, CP43 showed a single negative circular dichroism band at 670 nm. The pigment content of the complexes was determined by both spectroscopic measurements and HPLC. Contents of 18 chlorophylls a and 5 beta-carotenes per CP43 polypeptide and 19 chlorophylls a and 3 beta-carotenes per CP47 polypeptide were found, using the methods of Lowry or Bradford for protein quantitation. When the protein concentration was determined from the amino acid analysis, 20 chlorophylls a and 5 beta-carotenes per CP43 and 21-22 chlorophylls a and 4 beta-carotenes per CP47 were obtained. Thus, a content of 46-48 chlorophylls a was obtained for the core complex, assuming 4-6 chlorophylls per reaction center, in agreement with the composition obtained experimentally using a highly purified oxygen-evolving core complex. This suggested that no pigments were lost during the purification procedure. Moreover, the amino acid analysis of the purified complexes revealed a high homology with the amino acid composition derived from the gene sequences reported for other higher plants.