Stefano J E
Cell. 1984 Jan;36(1):145-54. doi: 10.1016/0092-8674(84)90083-7.
The small ribonucleoproteins recognized by anti-La sera consist mainly of RNA polymerase III products complexed with an antigenic cellular protein of 50 kd. A biochemical procedure for purifying the La protein from HeLa cells is described. The interaction of the isolated protein with a collection of model tRNA precursors, generated by ligation of specific oligonucleotides to the 3' terminus of yeast tRNAPhe, was studied. The most stable complexes are formed with adducts possessing three or four terminal uridylate residues. Addition of a terminal phosphate, fragmentation of the RNA, or substitution of other nucleotides reduce the affinity for the La protein. The preferred terminal sequence recognized and bound by La protein is homologous to the transcriptional termination signal for RNA polymerase III.
抗La血清识别的小核糖核蛋白主要由与一种50kd的抗原性细胞蛋白复合的RNA聚合酶III产物组成。本文描述了一种从HeLa细胞中纯化La蛋白的生化方法。研究了分离出的蛋白与一系列模型tRNA前体的相互作用，这些前体是通过将特定寡核苷酸连接到酵母苯丙氨酸tRNA的3'末端而产生的。最稳定的复合物是与具有三个或四个末端尿苷酸残基的加合物形成的。添加末端磷酸基团、RNA片段化或其他核苷酸替代会降低对La蛋白的亲和力。La蛋白识别并结合的优选末端序列与RNA聚合酶III的转录终止信号同源。
