Induction of resistance to alkylating agents in E. coli: the ada+ gene product serves both as a regulatory protein and as an enzyme for repair of mutagenic damage.

在大肠杆菌中诱导对烷化剂的抗性: ada + 基因产物既用作调节蛋白又用作修复诱变损伤的酶。

• 影响指数: 14.012
• 发表时间: Sep 1984
• 来源期刊: EMBO J
• PMID: 6092060
• 文章类型: Journal Article
• 中科院分区: Q1
• 方向: 生物
• 作者列表: Teo I,Sedgwick B,Demple B,Li B,Lindahl T

Mesh: Alkylating Agents / toxicity; Bacterial Proteins / genetics; DNA Repair; Drug Resistance, Microbial; Escherichia coli / drug effects genetics; Genes; Genes, Bacterial; Genes, Regulator; Methyltransferases / genetics; Nucleic Acid Hybridization; O(6)-Methylguanine-DNA Methyltransferase; Phenotype; Plasmids

Abstract

The expression of several inducible enzymes for repair of alkylated DNA in Escherichia coli is controlled by the ada+ gene. This regulatory gene has been cloned into a multicopy plasmid and shown to code for a 37-kd protein. Antibodies raised against homogeneous O6-methylguanine-DNA methyltransferase (the main repair activity for mutagenic damage in alkylated DNA) were found to cross-react with this 37-kd protein. Cell extracts from several independently derived ada mutants contain variable amounts of an altered 37-kd protein after an inducing alkylation treatment. In addition, an 18-kd protein identical with the previously isolated O6-methyl-guanine-DNA methyltransferase has been identified as a product of the ada+ gene. The smaller polypeptide is derived from the 37-kd protein by proteolytic processing.