Chereskin B M, Gantt E
Arch Biochem Biophys. 1986 Nov 1;250(2):286-93. doi: 10.1016/0003-9861(86)90729-0.
A 50-kDa polypeptide was obtained from photosynthetically active phycobilisome-photosystem II preparations from the red alga Porphyridium cruentum after removal of phycobiliproteins. Removal of phycobiliproteins caused destabilization of the structure of the phycobilisome-photosystem II preparations and was accompanied by a decline in photosystem II activity (oxygen-evolution and dichlorophenol-indophenol (DPIP) reduction). The treatments in increasing relative effectiveness were: addition of EDTA (10 mM), lowering the pH (6.8----4.4), and lowering the ionic strength (to ca. 1 mM phosphate). The lowering of the ionic strength by dialysis resulted in a preparation highly enriched in a 50-kDa polypeptide (apparent molecular mass on SDS-PAGE). This preparation retained photosystem II activity as evidenced by the photoreduction of DPIP in the presence of diphenylcarbazide (222 mumol DPIP/mg chlorophyll/h). Also it had a 698-nm (77K) fluorescence emission maximum, as compared to a 668-nm emission in the unfractionated preparation, which indicates enrichment of the photosystem II reaction center. Comparing our results with those obtained from green plants and a cyanobacterium leads us to suggest that the reaction center II polypeptides are highly similar in all chlorophyll alpha-containing plants.
从红藻紫球藻的光合活性藻胆体 - 光系统II制剂中去除藻胆蛋白后，获得了一种50 kDa的多肽。去除藻胆蛋白导致藻胆体 - 光系统II制剂的结构不稳定，并伴随着光系统II活性（放氧和二氯酚靛酚（DPIP）还原）的下降。相对有效性递增的处理方法依次为：添加EDTA（10 mM）、降低pH值（从6.8降至4.4）以及降低离子强度（至约1 mM磷酸盐）。通过透析降低离子强度得到了一种高度富集50 kDa多肽的制剂（SDS - PAGE上的表观分子量）。在存在二苯卡巴肼的情况下，该制剂能使DPIP发生光还原，这证明其保留了光系统II活性（222 μmol DPIP/（mg叶绿素·h））。此外，与未分级制剂中668 nm的发射峰相比，它在77K时有698 nm的荧光发射最大值，这表明光系统II反应中心得到了富集。将我们的结果与从绿色植物和一种蓝细菌中获得的结果进行比较，使我们推测在所有含叶绿素α的植物中，反应中心II多肽高度相似。
