Beck D P, Levine R P
J Cell Biol. 1974 Dec;63(3):759-72. doi: 10.1083/jcb.63.3.759.
The synthesis of the major chloroplast membrane polypeptides has been studied during synchronous growth of Chlamydomonas reinhardtii. Under these conditions, chlorophyll is synthesized during the latter part of the light period and cell division takes place during the dark period. The profile of the chloroplast membrane polypeptides of C. reinhardtii has been well characterized and shown to contain two major classes by size (Hoober, J. 1970. J. Biol. Chem.245:4327). Polypeptides of group I have a mol wt range of 50,000-55,000 daltons. The second region consists of at least three polypeptide groups, IIa, IIb, and IIc, having mol wt of 40,000, 31,000, and 27,000 daltons, respectively. The synthesis of these polypeptides has been measured using a double-labeling technique and a computer-aided statistical analysis. The rate of labeling of group I polypeptides is highest during the early light period and decreases after 6 h of growth. Group IIa is labeled from the beginning of the light period, but little synthesis of IIb occurs before 3 h, and significant amounts of label are not found in IIc before 5 h of growth. After approximately 8 h of light, groups IIb and IIc are synthesized at rates significantly greater than those of the other membrane polypeptides. The synthesis of the major polypeptide groups ceases in the dark. We conclude that the biosynthesis of the chloroplast membranes is a sequential or stepwise process.
在莱茵衣藻同步生长过程中，对其主要叶绿体膜多肽的合成进行了研究。在这些条件下，叶绿素在光照期的后期合成，细胞分裂则在黑暗期发生。莱茵衣藻叶绿体膜多肽的图谱已得到充分表征，并按大小显示包含两大类（胡伯，J. 1970. 《生物化学杂志》245:4327）。第一组多肽的分子量范围为50,000 - 55,000道尔顿。第二个区域至少由三个多肽组组成，即IIa、IIb和IIc，分子量分别为40,000、31,000和27,000道尔顿。已使用双标记技术和计算机辅助统计分析来测定这些多肽的合成情况。第一组多肽的标记速率在光照期早期最高，生长6小时后下降。IIa组从光照期开始就被标记，但IIb在3小时前几乎没有合成，在生长5小时前IIc中未发现大量标记。光照约8小时后，IIb和IIc组的合成速率明显高于其他膜多肽。主要多肽组的合成在黑暗中停止。我们得出结论，叶绿体膜的生物合成是一个顺序或逐步的过程。
