Fabijanski S, Pellegrini M
Mol Gen Genet. 1981;184(3):551-6. doi: 10.1007/BF00352539.
We have identified proteins involved in the peptidyl-tRNA-binding site of rat liver ribosomes, using an affinity label designed specifically to probe the P-site in eukaryotic peptidyl transferase. The label is a 3'-terminal pentanucleotide fragment of N-acetylleucyl-tRNA in which mercury atoms have been added at the C-5 position of the three cytosine residues. This mercurated fragment can bind to rat liver peptidyl transferase and function as a donor of N-acetylleucine to puromycin. Concomitant with this binding, the mercury atoms present in the fragment can form a covalent linkage with a small number of ribosomal proteins. The major proteins labeled by this reagent are L5 and L36A. Four protein spots are found labeled to a lesser extent: L10, L7/7a, L3/4 and L25/31. Each of these proteins, therefore, is implicated in the binding of the 3'-terminus of peptidyl-tRNA. The results presented here are correlated with other investigations of the structure-function aspects of rat liver peptidyl transferase. Using these data, we have constructed a model for the arrangement of proteins within this active site.
我们使用一种专门设计用于探测真核肽基转移酶中P位点的亲和标记，鉴定了大鼠肝脏核糖体肽基-tRNA结合位点中涉及的蛋白质。该标记是N-乙酰亮氨酰-tRNA的3'-末端五核苷酸片段，其中在三个胞嘧啶残基的C-5位置添加了汞原子。这种汞化片段可以与大鼠肝脏肽基转移酶结合，并作为N-乙酰亮氨酸向嘌呤霉素的供体发挥作用。伴随着这种结合，片段中存在的汞原子可以与少量核糖体蛋白形成共价连接。用该试剂标记的主要蛋白质是L5和L36A。发现有四个蛋白点标记程度较低：L10、L7/7a、L3/4和L25/31。因此，这些蛋白质中的每一种都与肽基-tRNA的3'-末端结合有关。这里给出的结果与对大鼠肝脏肽基转移酶结构-功能方面的其他研究相关。利用这些数据，我们构建了该活性位点内蛋白质排列的模型。
