Menzel R, Gellert M
Cell. 1983 Aug;34(1):105-13. doi: 10.1016/0092-8674(83)90140-x.
DNA gyrase is the bacterial enzyme responsible for converting circular DNA to a negatively supercoiled form. We show that the synthesis of DNA gyrase is itself controlled by DNA supercoiling; synthesis is highest when the DNA template is relaxed. The rates of synthesis in vivo of both the A and B subunits of DNA gyrase are increased up to 10-fold by treatments that block DNA gyrase activity and decrease the supercoiling of intracellular DNA. Similarly, efficient synthesis of both gyrase subunits in a cell-free S-30 extract depends on keeping the closed circular DNA template in a relaxed conformation. The results suggest that DNA supercoiling in E. coli is controlled by a homeostatic mechanism. Synthesis of the RecA protein and several other proteins is also increased by treatments that relax intracellular DNA.
DNA促旋酶是一种细菌酶，负责将环状DNA转变为负超螺旋形式。我们发现，DNA促旋酶的合成本身受DNA超螺旋控制；当DNA模板处于松弛状态时，合成量最高。通过阻断DNA促旋酶活性并降低细胞内DNA超螺旋的处理，DNA促旋酶A和B亚基在体内的合成速率提高了10倍。同样，在无细胞S-30提取物中高效合成这两种促旋酶亚基，取决于将闭环环状DNA模板保持在松弛构象。结果表明，大肠杆菌中的DNA超螺旋受一种稳态机制控制。通过使细胞内DNA松弛的处理，RecA蛋白和其他几种蛋白质的合成也会增加。
