Khodarev N N, Morozov A Iu, Sokolova I A, Aleksandrova S S, Votrin I I
Mol Gen Mikrobiol Virusol. 1988 Sep(9):26-32.
Fragmentation of the plasmid pBR322 DNA by a purified preparation of Ca/Mg-dependent endonuclease has been studied. It was shown that on the first steps of reaction the double-stranded cuts are introduced into the superhelical DNA independent of singlestranded ones. The doublestranded cuts are introduced into superhelical and linear DNA in 12 sites enriched with GC-pairs, 9 of them include pentanucleotide CGCGG(CCGCC) that is functionally significant. Relaxation of the plasmid DNA by topoisomerase I blocks the sitespecific action of the enzyme. Ca/Mg-dependent endonuclease is concluded to be topologically dependent enzyme, possibly, participating in the recombination processes.
对纯化的钙/镁依赖性核酸内切酶切割质粒pBR322 DNA的过程进行了研究。结果表明，在反应的第一步，双链切口被引入超螺旋DNA中，与单链切口无关。双链切口在富含GC碱基对的12个位点被引入超螺旋和线性DNA中，其中9个位点包含功能上重要的五核苷酸CGCGG(CCGCC)。拓扑异构酶I使质粒DNA松弛会阻断该酶的位点特异性作用。得出结论，钙/镁依赖性核酸内切酶是一种拓扑依赖性酶，可能参与重组过程。
