一种来自凝结芽孢杆菌的独特限制性内切酶BcgI。

Kong H, Morgan R D, Maunus R E, Schildkraut I

New England Biolabs, Inc., Beverly, MA 01915.

Nucleic Acids Res. 1993 Feb 25;21(4):987-91. doi: 10.1093/nar/21.4.987.

We have purified and characterized a new restriction endonuclease, BcgI, which has properties unlike those of the three recognized classes of restriction enzymes. BcgI was isolated from Bacillus coagulans, and it recognizes the sequence CGAN6TGC. BcgI cleaves double stranded DNA on both strands upstream and downstream of the recognition sequence, so that the recognition sequence is released as a 34-base pair fragment with 2-base 3'-extensions. Mg++ and S-adenosylmethionine are required for cleavage. Sinefungin, a structural analogue of AdoMet which generally inhibits methylase activity, can replace AdoMet in the cleavage reaction. The apparent binding constant (Kappd) for AdoMet is about 100 nM, while the KappD for sinefungin is about 500 nM.

我们已经纯化并鉴定了一种新的限制性内切酶BcgI，其特性与三种已确认的限制性酶类不同。BcgI是从凝结芽孢杆菌中分离出来的，它识别序列CGAN6TGC。BcgI在识别序列上下游的两条链上切割双链DNA，从而使识别序列作为一个带有2个碱基3'端延伸的34碱基对片段被释放出来。切割需要Mg++和S-腺苷甲硫氨酸。Sinefungin是AdoMet的一种结构类似物，通常抑制甲基化酶活性，它可以在切割反应中替代AdoMet。AdoMet的表观结合常数（Kappd）约为100 nM，而sinefungin的KappD约为500 nM。