Nika H, Hultin T
Biochim Biophys Acta. 1979 Jul 25;579(1):10-9. doi: 10.1016/0005-2795(79)90082-5.
A disulfide complex is formed in situ under gentle conditions between two neighbouring proteins in the 60-S subunits of mammalian ribosomes. The proteins have been identified as L 4 and L 29. The complex is easily isolated from whole ribosomes, and can be utilized for preparing the two proteins in a very pure state for further characterization. Chymotryptic cleavage of the complex or the isolated larger protein (L 4) in the presence of SDS produces two unequal fragments of this protein in nearly quantitative yield. The smaller fragment (approx. 12 000 daltons) contains the contact sequence. Only this fragment of protein L 4 is labelled when rat liver ribosomes are incuabted with iodo[14C]acetate under conditions of complex formation. Protein L 29 is resistant to chymotrypsin in the presence of sodium dodecyl sulfate.
在温和条件下，哺乳动物核糖体60 - S亚基中相邻的两个蛋白质之间会原位形成二硫键复合物。已鉴定出这两种蛋白质为L4和L29。该复合物很容易从完整核糖体中分离出来，可用于制备处于非常纯的状态的这两种蛋白质，以便进行进一步表征。在SDS存在下对复合物或分离出的较大蛋白质（L4）进行胰凝乳蛋白酶切割，几乎能以定量产率产生该蛋白质的两个不等的片段。较小的片段（约12000道尔顿）包含接触序列。当在复合物形成条件下将大鼠肝脏核糖体与碘代[14C]乙酸盐一起孵育时，只有蛋白质L4的这个片段会被标记。在十二烷基硫酸钠存在下，蛋白质L29对胰凝乳蛋白酶具有抗性。
