N+离子注入诱变筛选胸腺嘧啶缺陷型大肠杆菌

摘要

Escherichia coli was mutated with N+ ions implantation and the thymineless mutants was screened selectively by trimethoprim. The gene encoding thymidylate synthase(TS) from mutant was cloned into vector pMD-18T by recombinant DNA technology. It was found that the 173th base pairs were changed from AT to CG by gene-sequencing,thus the corresponding amino acid was changed from glutamic acid (E58) to alanine (A58). These studies are to provide a good basis for the further study of pyrimidine nucleotide metabolism.%利用N+离子注入诱变大肠杆菌,经甲氧苄啶的选择性筛选,得到胸腺嘧啶营养缺陷型菌株.通过重组DNA技术将该突变株胸苷酸合成酶(TS)基因连接到载体pMD-18T质粒上,经测序发现TS基因第173个碱基由AT→CG,其相应的氨基酸由谷氨酸(E58)突变为丙氨酸(A58).该突变株的获得为后续研究嘧啶核苷酸的代谢奠定了基础.