Samuelsson T, Elias P, Lustig F, Axberg T, Fölsch G, Akesson B, Lagerkvist U
J Biol Chem. 1980 May 25;255(10):4583-8.
Using a protein synthesizing in vitro system programmed with MS2-RNA, the ability of alanine tRNAs with the anticodons UGC (U represents 5-oxyacetic acid uridine monophosphate) and IGC to read the alanine codons in the coat protein cistron of MS2 has been determined both under conditions of no competition, where the alanyl-tRNA used was the only aminoacylated tRNAAla present in the system, and in experiments where the two alanyl-tRNAs were competing against each other. Under conditions of no competition, each of the anticodons can read all four alanine codons. However, when the anticodons compete for the codon GCC, the anticodon IGC, which can read all three positions of the codon according to the rules of Watson-Crick base pairing, is considerably more efficient than UGC, which misreads the codon by reading only the first two positions and presumably disregards the third nucleotide of the codon. The outcome of the competition experiments also reveals two apparent violations of the wobble restrictions: the anticodon UGC reads the codon GUU almost as effectively as does the anticodon IGC, and IGC is almost as effective as U*GC in reading the codon GCG.
利用用MS2 - RNA编程的体外蛋白质合成系统，在无竞争条件下（即所用的丙氨酰 - tRNA是系统中唯一氨酰化的tRNAAla）以及在两种丙氨酰 - tRNA相互竞争的实验中，测定了反密码子为UGC（U代表5 - 氧乙酸尿苷单磷酸）和IGC的丙氨酸tRNA读取MS2外壳蛋白顺反子中丙氨酸密码子的能力。在无竞争条件下，每个反密码子都能读取所有四个丙氨酸密码子。然而，当反密码子竞争密码子GCC时，根据沃森 - 克里克碱基配对规则能读取密码子所有三个位置的反密码子IGC，比只读取前两个位置从而误读密码子且可能忽略密码子第三个核苷酸的UGC效率高得多。竞争实验的结果还揭示了两个明显违反摆动限制的情况：反密码子UGC读取密码子GUU的效率几乎与反密码子IGC相同，并且IGC读取密码子GCG的效率几乎与U*GC相同。
