STUDY OF FUNCTIONS INVOLVED IN GENETIC RECOMBINATION

DNA促旋酶与127 - 256碱基DNA片段的复合物 通过电二色性方法研究了长度对。 的 结果表明，DNA以一个单一的环包裹在酶周围， 110个碱基对，入口点和出口点靠得很近。 其余 DNA以大约120度角的两条尾巴向外延伸 他们之间 在ATP或不可水解的ATP类似物的存在下， 尾部被包裹并结合到酶核心上。 这个过程是 被认为代表了超螺旋反应的中间阶段 DNA旋转酶。 配合物也正在研究中子散射方法。 初步结果与DNA单圈模型一致 与酶结合。

Complexes of DNA gyrase with defined DNA fragments from 127 to 256 base pairs in length have been studied by the method of electro-dichroism. The results suggest that DNA is wrapped around the enzyme in a single loop of 110 base pairs, with the entry and exit points close together. The rest of the DNA extends outward in two tails with an angle of about 120 degrees between them. In the presence of ATP or a nonhydrolyzable ATP analog, the tails are wrapped back and bound to the enzyme core. This process is considered to represent an intermediate stage in the supercoiling reaction of DNA gyrase. The complexes are also being studied by neutron scattering methods. Preliminary results are consistent with the model of a single turn of DNA bound to the enzyme.