Huang C, Berns D S
Arch Biochem Biophys. 1983 Jan;220(1):145-54. doi: 10.1016/0003-9861(83)90395-8.
The chlorophyll a-protein complexes of a blue-green alga, Phormidium luridum, are resolved in the absence of detergent, by the combination of a Sepharose 4B column and sucrose density gradient centrifugation, into six chlorophyll a-containing zones. These six complexes are termed here as F15, F25, F35, F40, F60, and F65, according to their appearance in the sucrose density gradient after centrifugation. The absorption spectra of these six isolated complexes are reported, as well as the fluorescence emission spectra at room temperature and liquid-nitrogen temperature. The F60 complex was enriched in Photosystem I, while the F35 and F40 complexes contained both Photosystem I and II. The F60 complex is the predominant band and accounts for about 49% of the total chlorophyll a of the cells. The extinction coefficient of this complex is determined to be 68.7 mM-1 cm-1 at 680 nm in 50 mM tris(hydroxymethyl)amino methane buffer at pH 8.0. In addition, the effect of the detergent, sodium dodecyl sulfate, on these spectra are also reported for comparison. The chemically induced difference spectra of F35, F40, and F60 complexes also indicate the presence of the reaction center, P700, of Photosystem I. These three complexes have been shown to contain P700 in a ratio of approximately one reaction center molecule per 100 light-harvesting chlorophyll molecules. The simple exposure of the F60 fraction to sodium dodecyl sulfate results in an "apparent" enhancement of the P700 to chlorophyll ratio to one P700 per 51 light harvesting chlorophyll. Room temperature electron spin resonance measurements of photooxidized F60 are consistent with the presence of P700 and with the chlorophyll/P700 ratio observed by chemical assay. The amino acid compositions of F60 and F65 complexes are studied. Gel electrophoresis patterns of these six isolated complexes are presented and are significantly different from those reported for detergent-treated chlorophyll-protein complexes.
通过结合琼脂糖4B柱和蔗糖密度梯度离心法，在不使用去污剂的情况下，将一种蓝绿藻—— luridum席藻的叶绿素a -蛋白复合物分离成六个含叶绿素a的区带。根据它们在离心后蔗糖密度梯度中的出现情况，这六个复合物在此处分别称为F15、F25、F35、F40、F60和F65。报道了这六种分离复合物的吸收光谱，以及室温下和液氮温度下的荧光发射光谱。F60复合物富含光系统I，而F35和F40复合物同时含有光系统I和光系统II。F60复合物是主要条带，占细胞总叶绿素a的约49%。在pH 8.0的50 mM三（羟甲基）氨基甲烷缓冲液中，该复合物在680 nm处的消光系数测定为68.7 mM-1 cm-1。此外，还报道了去污剂十二烷基硫酸钠对这些光谱的影响以供比较。F35、F40和F60复合物的化学诱导差异光谱也表明存在光系统I的反应中心P700。已证明这三种复合物中P700的含量约为每100个捕光叶绿素分子中有一个反应中心分子。将F60组分简单暴露于十二烷基硫酸钠会导致P700与叶绿素的比例“明显”提高到每51个捕光叶绿素中有一个P700。对光氧化的F60进行室温电子自旋共振测量，结果与P700的存在以及化学分析观察到的叶绿素/P700比例一致。研究了F60和F65复合物的氨基酸组成。给出了这六种分离复合物的凝胶电泳图谱，它们与报道的经去污剂处理的叶绿素 - 蛋白复合物的图谱有显著差异。
