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：1990
卷号：87
期号：10
页码：3957-3961
DOI：10.1073/pnas.87.10.3957
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：By using site-directed oligonucleotide mutagenesis, amber nonsense stop codons (5'-TAG-3') have been introduced at 20 sites in the Escherichia coli thymidylate synthase gene. By transforming the thyA mutant plasmids into 13 strains, each of which harbor different amber suppressor tRNAs, we were able to generate over 245 amino acid substitutions in E. coli thymidylate synthase (EC 2.1.1.45 ). Growth characteristics of these mutants have been studied, yielding a body of information that includes some surprising results in light of the recently published crystal structure of the enzyme.
