Süss K H, Schmidt O, Machold O
Biochim Biophys Acta. 1976 Sep 21;448(1):103-13. doi: 10.1016/0005-2736(76)90079-1.
Envelope- and stroma-free thylakoid membranes of Vicia faba chloroplasts were incubated with trypsin or pronase for several hours. The indigestible residue was analysed by polyacrylamide gel electrophoresis. Trypsinization resulted in a complete digestion of all proteins with the exception of the pigment-protein complexes as well as a polypeptide not yet characterized. Yet, as compared with untreated material, Complex II was found to have higher electrophoretic mobility. Electron-microscopic studies illustrate that the indigestible residue still has a preserved membrane structure. Disintegration of the thylakoid membranes by sodium dodecyl sulfate followed by trypsinization also resulted in the two complexes while all the other proteins were found to be digested. However, after removal of the lipids the protein moieties of the complexes proved to be easily digestible. From these results it is concluded that pigment-protein interaction may be an important factor in maintaining a conformation rather resistant to perturbants and proteases. In contrast to trypsin, pronase completely digested the polypeptides of the thylakoid membranes including the protein moieties of the pigment-protein complexes leaving an amorphous lipid mass. The results support the assumption that the complexes are necessary to maintain the membrane structure.
将蚕豆叶绿体无包膜和基质的类囊体膜与胰蛋白酶或链霉蛋白酶一起孵育数小时。用聚丙烯酰胺凝胶电泳分析不可消化的残渣。胰蛋白酶处理导致除色素 - 蛋白质复合物以及一种尚未鉴定的多肽外的所有蛋白质完全消化。然而，与未处理的材料相比，发现复合物II具有更高的电泳迁移率。电子显微镜研究表明，不可消化的残渣仍保留有完整的膜结构。用十二烷基硫酸钠使类囊体膜解体，然后进行胰蛋白酶处理，也产生了这两种复合物，而发现所有其他蛋白质都被消化了。然而，去除脂质后，复合物的蛋白质部分很容易被消化。从这些结果可以得出结论，色素 - 蛋白质相互作用可能是维持对干扰物和蛋白酶具有相当抗性的构象的一个重要因素。与胰蛋白酶不同，链霉蛋白酶完全消化了类囊体膜的多肽，包括色素 - 蛋白质复合物的蛋白质部分，只留下无定形的脂质团块。这些结果支持了复合物对于维持膜结构是必需的这一假设。
