期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2003
卷号：100
期号：13
页码：7471-7475
DOI：10.1073/pnas.1332771100
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The genetic code was established through aminoacylations of RNA substrates that emerged as tRNAs. The 20 aminoacyl-tRNA synthetases (one for each amino acid) are ancient proteins, the active-site domain of which catalyzes formation of an aminoacyl adenylate that subsequently reacts with the 3' end of bound tRNA. Binding of tRNA depends on idiosyncratic (to the particular synthetase) domains and motifs that are fused to or inserted into the conserved active-site domain. Here we take the domain for synthesis of alanyl adenylate and fuse it to ``artificial'' peptide sequences (28 aa) that were shown previously to bind to the acceptor arm of tRNAAla. Certain fusions confer aminoacylation activity on tRNAAla and on hairpin microhelices modeled after its acceptor stem. Aminoacylation was sensitive to the presence of a specific G:U base pair known to be a major determinant of tRNAAla identity. Aminoacylation efficiency and specificity also depended on the specific peptide sequence. The results demonstrate that barriers to RNA-specific aminoacylations are low and can be achieved by relatively simple peptide fusions. They also suggest a paradigm for rationally designed specific aminoacylations based on peptide fusions.
