Shpaer E G
Institute of Organic Synthesis, Latvian SSR Academy of Sciences, Riga, USSR.
Protein Seq Data Anal. 1989 Feb;2(2):107-10.
Amino acid occurrence frequencies were found for four groups of Escherichia coli proteins with different abundance levels in the cell. These frequencies decrease with increasing protein abundance for amino acids whose codons are translated by tRNAs present at low concentrations (e.g., Cys, Trp, Ser, etc.); the opposite tendency was observed for amino acids translated by abundant tRNAs (Lys, Val, etc.). The efficiency (rate and accuracy) of codon translation is expected to be proportional to the concentration of the cognate tRNA. Therefore, the observed constraints on amino acid composition may be explained as resulting from evolutionary pressure optimizing the translational efficiency of a gene (the same pressure is responsible for the nonrandom choice of synonymous codons).
研究发现了细胞中具有不同丰度水平的四组大肠杆菌蛋白质的氨基酸出现频率。对于那些密码子由低浓度存在的tRNA翻译的氨基酸（例如半胱氨酸、色氨酸、丝氨酸等），这些频率随着蛋白质丰度的增加而降低；而对于由丰度高的tRNA翻译的氨基酸（赖氨酸、缬氨酸等），则观察到相反的趋势。密码子翻译的效率（速率和准确性）预计与同源tRNA的浓度成正比。因此，观察到的对氨基酸组成的限制可以解释为是由优化基因翻译效率的进化压力导致的（同样的压力也导致了同义密码子的非随机选择）。
