Mitra S K, Lustig F, Akesson B, Axberg T, Elias P, Lagerkvist U
J Biol Chem. 1979 Jul 25;254(14):6397-401.
Using a protein synthesizing in vitro system programmed with MS 2-RNA, the relative efficiency (in the presence of each other) of valine tRNAs with the anticodons UAC (U represents 5-oxyacetic acid uridine monophosphate), GAC, and IAC to read the valine codons was investigated. An anticodon which can read all three positions of the codon according to the rules of Watson-Crick base-pairing and the wobble hypothesis is an order of magnitude more efficient than an anticodon which misreads the codon by reading only the first two positions and presumably disregards the third nucleotide of the codon. There are two seeming exceptions to this behavior: the anticodon UAC reads the codon GUU quite efficiently and IAC is as effective as UAC in reading the codon GUG. The significance of these exceptions is evaluated with respect to the organization and evolution of the genetic code.
利用用MS 2 - RNA编程的体外蛋白质合成系统，研究了带有反密码子UAC（U代表5 - 氧代乙酸尿苷单磷酸）、GAC和IAC的缬氨酸tRNA在相互存在时读取缬氨酸密码子的相对效率。根据沃森 - 克里克碱基配对规则和摆动假说，能够读取密码子所有三个位置的反密码子比仅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反密码子效率高一个数量级。这种行为有两个明显的例外：反密码子UAC能相当有效地读取密码子GUU，并且IAC在读取密码子GUG时与UAC一样有效。针对遗传密码的组织和进化对这些例外的意义进行了评估。
