Alfonso M, Montoya G, Cases R, Rodríguez R, Picorel R
Departamento de Nutrición Vegetal, Estación Experimental de Aula Dei (CSIC), Zaragoza, Spain.
Biochemistry. 1994 Aug 30;33(34):10494-500. doi: 10.1021/bi00200a034.
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 Qy 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, 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.(ABSTRACT TRUNCATED AT 250 WORDS)
利用离液剂高氯酸锂和非离子去污剂β-十二烷基麦芽糖苷的组合，通过阴离子交换色谱法从两种高等植物中纯化了光系统II的核心天线复合物CP43和CP47。在48K下，CP43的Qy跃迁在682.3和671.5nm附近分解为两个主要谱带，而CP47光谱显示出更复杂的结构，主要谱带位于688、681.2、676、667和661nm处。CP43和CP47在77K下的发射谱带分别在683和695nm处被检测到。荧光激发光谱表明叶绿素不同跃迁之间的能量转移效率很高，而来自β-胡萝卜素的能量转移效率略低。CP47的圆二色光谱表明一些叶绿素之间存在激子相互作用。相比之下，CP43在670nm处显示出单一的负圆二色谱带。通过光谱测量和高效液相色谱法测定了复合物的色素含量。使用Lowry或Bradford方法进行蛋白质定量，发现每个CP43多肽含有18个叶绿素a和5个β-胡萝卜素，每个CP47多肽含有19个叶绿素a和3个β-胡萝卜素。当根据氨基酸分析确定蛋白质浓度时，每个CP43获得20个叶绿素a和5个β-胡萝卜素，每个CP47获得21 - 22个叶绿素a和4个β-胡萝卜素。因此，假设每个反应中心有4 - 6个叶绿素，则核心复合物的叶绿素a含量为46 - 48个，这与使用高度纯化的放氧核心复合物通过实验获得的组成一致。（摘要截短至250字）
