Machulin A V, Deriusheva E I, Iunusova A K, Zheleznaia L A, Serdiuk I N
Biofizika. 2012 May-Jun;57(3):432-6.
Nicking endonuclease Nt.BspD6I is a heterodimeric restriction endonuclease, one subunit of which exhibits specific nicking activity. It gets bound to double-stranded DNA and makes a break (nick) in one chain at a distance of 4 nucleotides from the binding site. In this work, for visualization of the specific binding and protein landing site an atomic force microscopy was used. In five minutes after incubation of DNA solution with nicking endonuclease, the DNA molecules with associated proteins which located at the expected binding site and "shared" DNA strand into two segments (approximately, 1/3 and 2/3 of length) were observed in the images. In addition, near the binding site DNA molecule had a height corresponding to a single-stranded DNA molecule, which was in good agreement with single-stranded cleavage by nickase in the course of complex formation.
切口核酸内切酶Nt.BspD6I是一种异源二聚体限制性核酸内切酶，其一个亚基具有特异性切口活性。它与双链DNA结合，并在距结合位点4个核苷酸的位置在一条链上产生一个断裂（切口）。在这项工作中，为了可视化特异性结合和蛋白质着陆位点，使用了原子力显微镜。在用切口核酸内切酶孵育DNA溶液五分钟后，在图像中观察到与蛋白质相关的DNA分子，这些蛋白质位于预期的结合位点，并将“共享”的DNA链分成两段（长度大约为1/3和2/3）。此外，在结合位点附近，DNA分子的高度与单链DNA分子相对应，这与在复合物形成过程中切口酶对单链的切割情况非常吻合。
