Structural studies on the protein synthesis machinery

在所有活细胞中，蛋白质的合成都是在称为核糖体的细胞器中进行的。这些大的核糖核蛋白复合体通常由大小不等的两个亚基组成。在原核大肠杆菌核糖体中，大的(50S)亚基由34个蛋白质和5S和23S rRNA组成，而小的(30S)亚基是由21个蛋白质和16S rRNA组成的复合体。在这个项目中，我们分析了三种核糖体蛋白质的结构，这些蛋白质位于核糖体的肽基转移酶中心。它们是L2、L5和L13。L2蛋白被认为是肽基转移酶中心最重要的组成部分。也就是说，亲和标记研究已经将蛋白质L2定位在50S核糖体亚基的肽基转移酶中心或附近。L5是5S rRNA结合蛋白之一，L13是23S rRNA结合蛋白。这些结构分析表明，核糖体蛋白是结构研究的独特靶点。它们为蛋白质进化和蛋白质合成机制提供了新的见解。

In all living cells, protein synthesis is carried out in cellular organelles called ribosomes. These large ribonucleoprotein complexes are generally organized in two subunits of unequal size. In prokaryotic Escherichia coli ribosomes, the large (50S) subunit consists of 34 proteins and 5S and 23S rRNAs, while the small (30S) subunit is a complex of 21 proteins and 16S rRNA.All these proteins have been localized in the ribosome by immunoelectron microscopy and neutron scattering. In this project, we analyzed structures of three ribosomal proteins in the peptidyl transferase center of the ribosome. They are L2, L5 and L13. The protein L2 is known to be most important constituent of the peptidyl transferase center. That is, affinity-labeling studies have localized the protein L2 at or near the peptidyl transferase center of the 50S ribosomal subunit. L5 is one of the 5S rRNA binding protein and L13 is 23S rRNA binding protein. These structure analyses have demonstrated that ribosomal proteins represent unique targets for structural study. They provide new insights into protein evolution as well as protein-synthesizing machinery.