Identification of New Ribosomal Proteins and the Snalysis of the Change of Ribosomal Structure During the Transition of Cell Growth Phase in Escherichia Coli

我们建立了一种无自由基高还原(RFHR)的双向聚丙烯酰胺凝胶电泳法，鉴定了大肠杆菌核糖体的五个新的蛋白质组分(A、B、C、D和E)。对这些新成分的氨基酸序列进行了分析，并确定了所有的基因座。也就是说，A、B、C、D和E的基因分别定位在37.6‘、72’、88.5‘、33’和22‘。根据对大肠杆菌核糖体蛋白的统一命名，将蛋白A、B、C和D分别命名为L35、L36、Pre L31和S22。自1971年命名法建立以来，在大肠杆菌中发现的新核糖体蛋白是独一无二的。蛋白E被归类为核糖体因子，因为在核糖体纯化过程中，蛋白E在高盐洗涤过程中从核糖体颗粒中释放出来。蛋白E随细胞生长的变化与细胞生长稳定期形成的70S二聚体(100S)有较强的平行关系。蛋白E存在于100S而不是70S单体或游离的50S、30S亚基中。蛋白质E与100S的摩尔比为1：1。这些结果表明，蛋白E可能连接两个70年代的核糖体，形成失去蛋白质溴合成活性的100个核糖体。100s是核糖体的第四种模式，可能是等待细胞生长环境改善的一种形式。

We developed a radical-free and highly reducing (RFHR) method of two dimensional polyacrylamide gel electrophoresis and identified five new protein components (A, B, C, D, and E) of E. coli ribosomes. The amino acid sequences of these new components were analyzed and all the gene loci were determined. That is to say, genes for A, B, C, D and E were localized at 37.6', 72', 88.5', 33' and 22', respectively. Proteins A, B, C and D were named L35, L36, pre L31 and S22, respectively, according to a unified nomenclature for E. coli ribosomal proteins. The discovery of the new ribosomal proteins in E. coli is unique since the establishment of the nomenclature in 1971. Protein E was classified as a ribosomal factor, because it released from ribosomal particles during high salt washing in the purification of ribosomes. The change of protein E dependent on the cell growth showed a strong pararellism with that of 70S dimer (100S), which was formed in the stationary phase of the cell growth. Protein E exists in 100S but not 70S monomer or free 50S, 30S subunits. The molar ratio of protein E to 100S is one to one. These results suggest that protein E may connect two 70S ribosomes and form 100S which has lost the activity of protein brosynthesis. The 100S, the forth mode of ribosomes, may be a form waiting for an improvement of the environment for the cell growth.