Traut R R, Lambert J M, Kenny J W
J Biol Chem. 1983 Dec 10;258(23):14592-8.
The 50 S ribosomal subunits from Escherichia coli were modified by reaction with 2-iminothiolane under conditions in which 65 sulfhydryl groups, about 2/protein, were added per subunit. Earlier work showed that protein L7/L12 was modified more extensively than the average but that nearly all 50 S proteins contained sulfhydryl groups. Mild oxidation led to the formation of disulfide protein-protein cross-links. These were fractionated by urea gel electrophoresis and then analyzed by diagonal gel electrophoresis. Cross-linked complexes containing two, three, and possibly four copies of L7/L12 were evident. Cross-links between L7/L12 and other ribosomal proteins were also formed. These proteins were identified as L5, L6, L10, L11, and, in lower yield, L9, L14, and L17. The yields of cross-links to L5, L6, L10, and L11 were comparable to the most abundant cross-links formed. Similar experiments were performed with 70 S ribosomes. Protein L7/L12 in 70 S ribosomes was cross-linked to proteins L6, L10, and L11. The strong L7/L12-L5 cross-link found in 50 S subunits was absent in 70 S ribosomes. No cross-links between 30 S proteins and L7/L12 were observed.
用2-亚氨基硫杂环戊烷与来自大肠杆菌的50 S核糖体亚基反应，在每个亚基添加约65个巯基（约2个/蛋白质）的条件下对其进行修饰。早期的研究表明，蛋白质L7/L12的修饰程度比平均水平更高，但几乎所有50 S蛋白质都含有巯基。温和氧化导致形成二硫键连接的蛋白质-蛋白质交联。这些交联产物通过尿素凝胶电泳进行分级分离，然后通过对角线凝胶电泳进行分析。含有两个、三个以及可能四个L7/L12拷贝的交联复合物很明显。L7/L12与其他核糖体蛋白质之间也形成了交联。这些蛋白质被鉴定为L5、L6、L10、L11，以及产量较低的L9、L14和L17。与L5、L6、L10和L11形成交联的产量与形成的最丰富的交联产量相当。用70 S核糖体进行了类似的实验。70 S核糖体中的蛋白质L7/L12与蛋白质L6、L10和L11交联。在50 S亚基中发现的强L7/L12-L5交联在70 S核糖体中不存在。未观察到30 S蛋白质与L7/L12之间的交联。
