PROOFREADING OF CODON-ANTICODON INTERACTION ON RIBOSOMES
PROOFREADING OF CODON-ANTICODON INTERACTION ON RIBOSOMES
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DOI：
10.1073/pnas.74.1.198
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发表时间：
1977-01-01
影响因子：
11.1
通讯作者：
STONE, PJ
中科院分区：
文献类型：
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作者：
THOMPSON, RC;STONE, PJ
蛋白质合成的精确度远大于密码子-反密码子识别的特异性，后者是根据已知的溶液中碱基配对的能量学所预期的。为了验证与GTP水解相关的动力学校正可以增加识别特异性的建议，研究了多肽延伸因子Tu、氨酰[aa]-tRNA和GTP与聚（U）-编程核糖体[来自大肠杆菌]的三元复合物的相互作用。对于大多数非同源三元复合物，包括与UUU的5“和3”碱基正确配对的2个复合物，在没有GTP水解的情况下发生排斥反应，推测是通过初始结合反应的逆转。含有Leu-或Ile-tRNA的复合物，可以与3“和中间碱基正确配对，刺激GTP水解，尽管aa-tRNA没有保留在核糖体上。因此，证明了核糖体上氨酰-tRNA识别中存在GTP依赖的校对步骤。密码子的5“碱基可能比中间碱基更容易出错，可以通过校对来纠正。
The fidelity of protein synthesis is substantially greater than the specificity of codon-anticodon recognition that would be expected from the known energetics of base-pairing in solution. To test the suggestion that the specificity of recognition may be increased by kinetic proofreading associated with GTP hydrolysis, the interaction of ternary complexes of polypeptide elongation factor Tu, aminoacyl[aa]-tRNA and GTP with poly(U)-programed ribosomes [from Escherichia coli] was studied. With most noncognate ternary complexes, including 2 that pair correctly with the 5'' and 3'' bases of UUU, rejection occurred without GTP hydrolysis, presumably by the reverse of the initial binding reaction. With complexes containing Leu- or Ile-tRNAs, which may pair correctly with the 3'' and middle bases, GTP hydrolysis was stimulated, though the aa-tRNA was not retained on the ribosome. The existence of a GTP-dependent proofreading step in aminoacyl-tRNA recognition on ribosomes is thus demonstrated. The 5'' base of the codon is probably more prone than the middle base to errors that can be corrected by proofreading.