Trucksis M, Depew R E
Proc Natl Acad Sci U S A. 1981 Apr;78(4):2164-8. doi: 10.1073/pnas.78.4.2164.
A gene that specifies production of Escherichia coli DNA topoisomerase I (omega protein) was identified with the aid of a radioimmunoassay for this protein. E. coli DNA topoisomerase I was produced by Salmonella typhimurium merodiploids that harbored E. coli plasmid F' 123, but not by strains that lost this plasmid. Analysis of strains with spontaneous deletions of F' 123 showed that the gene, topA, required for production of the E. coli omega protein was between the trp operon and the cysB gene. Deletions that eliminated topA also eliminated the supX gene. We suggest that topA is the structural gene of E. coli DNA topoisomerase I and that topA is identical to supX.
借助针对该蛋白的放射免疫测定法，鉴定出了一个指定大肠杆菌DNA拓扑异构酶I（ω蛋白）产生的基因。携带大肠杆菌质粒F' 123的鼠伤寒沙门氏菌部分二倍体可产生大肠杆菌DNA拓扑异构酶I，但丢失该质粒的菌株则不能产生。对F' 123自发缺失菌株的分析表明，产生大肠杆菌ω蛋白所需的基因topA位于色氨酸操纵子和cysB基因之间。消除topA的缺失也消除了supX基因。我们认为topA是大肠杆菌DNA拓扑异构酶I的结构基因，且topA与supX相同。
