PROTEIN-SYNTHESIS IN ISOLATED SPINACH-CHLOROPLASTS - COMPARISON OF LIGHT-DRIVEN AND ATP-DRIVEN SYNTHESIS
PROTEIN-SYNTHESIS IN ISOLATED SPINACH-CHLOROPLASTS - COMPARISON OF LIGHT-DRIVEN AND ATP-DRIVEN SYNTHESIS
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DOI：
10.1016/0003-9861(74)90012-5
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发表时间：
1974-01-01
影响因子：
3.9
通讯作者：
WHITFELD, PR
中科院分区：
文献类型：
--
作者：
BOTTOMLEY, W;SPENCER, D;WHITFELD, PR
比较了完整菠菜叶绿体中光驱动蛋白合成和断裂叶绿体中atp驱动蛋白合成所需的Mg2+和K+离子的最佳浓度，并通过聚丙烯酰胺凝胶电泳对两种体系的产物进行了比较。在含有蔗糖或山梨醇的缓冲系统中，完整叶绿体中氨基酸与多肽的光驱动结合被测定，因为渗透性被添加的Mg2+抑制，这种效应在低浓度（小于40 mm）的KCl下最为明显。另一方面，作为渗透剂悬浮在0.2mKCl中的叶绿体需要Mg2+(3 mm)才能达到最佳的光驱动蛋白质合成活性。在黑暗中，氨基酸被破碎的叶绿体掺入，补充ATP和GTP，需要9 mmMg2+才能达到最大活性。在光驱动的完整叶绿体体系中，对一价阳离子的需求最好由K+（约30 mm）填充，而在atp驱动的破碎叶绿体体系中，NH4+（约80 mm）的活性最高。光驱动的、完整的叶绿体和atp驱动的、破碎的叶绿体的产物的十二烷基硫酸钠-聚丙烯酰胺凝胶的自射线照相显示了质量上相似的模式。可溶性蛋白组分中至少有4种放射性多肽，主要产物与1组分蛋白的大亚基一致。在膜组分中，至少有9个离散产物可以被分解。
A comparison has been made of the optimal concentrations of Mg2+and K+ions necessary for both light-driven protein synthesis in intact spinach chloroplasts and for ATP-driven protein synthesis in broken chloroplasts, and the products of the two systems have been compared by polyacrylamide gel electrophoresis. Light-driven incorporation of amino acids into polypeptides in intact chloroplasts assayed in buffer systems containing sucrose or sorbitol as the osmoticum is inhibited by the addition of Mg2+, the effect being most marked at low concentrations (less than 40 mm) of KCl. On the other hand, chloroplasts suspended in 0.2mKCl as osmoticum require Mg2+(3 mm) for optimal light-driven protein-synthesizing activity. Incorporation of amino acids by broken chloroplasts in the dark, supplemented with ATP and GTP, requires 9 mmMg2+for maximum activity. A requirement for monovalent cations is best filled by K+(approx 30 mm) in the case of the light-driven, intact chloroplast system whereas, in the ATP-driven, broken chloroplast system, NH4+(approx 80 mm) gave the highest activity.Autoradiographs of Na dodecyl sulfate-polyacrylamide gels of the products from both the light-driven, intact chloroplasts and from the ATP-driven, broken chloroplasts reveal qualitatively similar patterns. There are at least four radioactive polypeptides in the soluble protein fraction the dominant product being coincident with the large subunit of Fraction 1 protein. In the membrane fraction at least nine discrete products can be resolved.