Shapovalova N I, Zheleznaia L A, Matvienko N I
Biokhimiia. 1994 Nov;59(11):1730-8.
The site-specific endonuclease R.BspKT6I and the cognate site-specific methylase M.BspKT6I have been isolated from the thermophilic strain of Bacillus species KT6 using gel-filtration on Sephadex G100 followed by chromatography on heparin-Sepharose and hydroxyapatite. Endonuclease BspKT6I is an isomer but not an isoschizomer of Sau3AI and MboI. It recognized on the DNA molecule the GAT decreases C sequence and cleaves it; however, unlike Sau3AI and MboI it produces 3'-protruding dinucleotides. The site cleavage is inhibited by dam-methylation. The sticky ends resulting from the BspKT6I cleavage are identical and complementary to the ends formed after the PvuI cleavage. The isolated from the B. species KT6 methylase protects the DNA from subsequent cleavage by BspKT6I. Adenine is a methylated base.
位点特异性内切核酸酶R.BspKT6I和同源位点特异性甲基化酶M.BspKT6I是从嗜热芽孢杆菌属KT6菌株中分离得到的，方法是先在葡聚糖凝胶G100上进行凝胶过滤，然后在肝素-琼脂糖和羟基磷灰石上进行色谱分离。内切核酸酶BspKT6I是Sau3AI和MboI的异构体，但不是同裂酶。它在DNA分子上识别GAT↓C序列并进行切割；然而，与Sau3AI和MboI不同的是，它产生3'突出的二核苷酸。位点切割受到dam甲基化的抑制。BspKT6I切割产生的粘性末端与PvuI切割后形成的末端相同且互补。从芽孢杆菌属KT6分离得到的甲基化酶可保护DNA免受BspKT6I的后续切割。腺嘌呤是被甲基化的碱基。
