体外蛋白质合成研究一直不能完全解释文献中所报道的活体蛋白质合成所具有的保真度。DNA 和RNA聚合酶复合物（它们将氨酰基- tRNA输送到核糖体A-点上）具有校对功能，但此前这种活性一直没有在核糖体本身中发现。
现在，Hani Zaher 和 Rachel Green发现了一个以前没有定性的、用于保证蛋白质合成的保真度的体系，该体系在肽键形成之后发挥作用。如果一个不正确的氨基酸被吸收进了一个正在生长的多肽链中，那么在核糖体的活性点上特异性一般就会丢失，导致错误累积，触发肽合成的过早结束。这种“后肽基转移编辑”（post-peptidyl transfer editing），在某种程度上可以解释活体蛋白质合成中所达到的给人印象深刻的保真度。（生物谷Bioon.com）
生物谷推荐原始出处：
Nature 457, 161-166 (8 January 2009) | doi:10.1038/nature07582
Quality control by the ribosome following peptide bond formation
Hani S. Zaher1 & Rachel Green1
1 Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
The overall fidelity of protein synthesis has been thought to rely on the combined accuracy of two basic processes: the aminoacylation of transfer RNAs with their cognate amino acid by the aminoacyl-tRNA synthetases, and the selection of cognate aminoacyl-tRNAs by the ribosome in cooperation with the GTPase elongation factor EF-Tu. These two processes, which together ensure the specific acceptance of a correctly charged cognate tRNA into the aminoacyl (A) site, operate before peptide bond formation. Here we report the identification of an additional mechanism that contributes to high fidelity protein synthesis after peptidyl transfer, using a well-defined in vitro bacterial translation system. In this retrospective quality control step, the incorporation of an amino acid from a non-cognate tRNA into the growing polypeptide chain leads to a general loss of specificity in the A site of the ribosome, and thus to a propagation of errors that results in abortive termination of protein synthesis.
