Jay G, Kaempfer R
Proc Natl Acad Sci U S A. 1974 Aug;71(8):3199-203. doi: 10.1073/pnas.71.8.3199.
It is shown that initiation of translation involves several steps. (i) Binding of fMet-tRNA(fMet) to the bacterial 30S ribosomal subunit in the absence of messenger RNA, yielding a 34S complex. This binding is rapid and dependent on initiation factor 2 but not on initiation factor 3. (ii) Binding of messenger RNA to the 34S complex. This binding is slower and depends on initiation factor 3. If R17 RNA is used as messenger, the resulting complex sediments at 46 S. (iii) Joining of a 50S subunit to yield a complete initiation complex. Binding of fMet-tRNA(fMet) not only precedes, but is necessary for, correct binding of messenger RNA to ribosomes. Thus, initiator tRNA may play an active role in the selection of initiation sites in messenger RNA.
结果表明,翻译起始涉及几个步骤。(i)在没有信使RNA的情况下,甲硫氨酸- tRNA(fMet)与细菌30S核糖体亚基结合,产生一个34S复合物。这种结合迅速,依赖于起始因子2,但不依赖于起始因子3。(ii)信使RNA与34S复合物结合。这种结合较慢,依赖于起始因子3。如果使用R17 RNA作为信使,产生的复合物在46 S处沉降。(iii)加入50S亚基以产生完整起始复合物。甲硫氨酸- tRNA(fMet)的结合不仅先于信使RNA与核糖体的正确结合,而且是其必要条件。因此,起始tRNA可能在信使RNA起始位点的选择中发挥积极作用。