Rodier F, Gabarro-Arpa J, Ehrlich R, Reiss C
Nucleic Acids Res. 1982 Jan 11;10(1):391-402. doi: 10.1093/nar/10.1.391.
The signal qualifying an AUG or GUG as an initiator in mRNAs processed by E. coli ribosomes is not found to be a systematic, literal homology sequence. In contrast, stability analysis reveals that initiators always occur within nucleic acid domains of low stability, for which a high A/U content is observed. Since no aminoacid selection pressure can be detected at N-termini of the proteins, the A/U enrichment results from a biased usage of the code degeneracy. A computer analysis is presented which allows easy detection of the codon strategy. N-terminal codons carry rather systematically A or U in third position, which suggests a mechanism for translation initiation and helps to detect protein coding sequences in sequenced DNA.
在由大肠杆菌核糖体加工的mRNA中,将AUG或GUG鉴定为起始密码子的信号并非系统的、字面上的同源序列。相反,稳定性分析表明,起始密码子总是出现在低稳定性的核酸结构域内,在这些结构域中观察到较高的A/U含量。由于在蛋白质的N端检测不到氨基酸选择压力,A/U富集是由于密码子简并性的偏向使用所致。本文提出了一种计算机分析方法,可轻松检测密码子策略。N端密码子在第三位相当系统地携带A或U,这提示了一种翻译起始机制,并有助于在测序DNA中检测蛋白质编码序列。