Jeltsch A, Wenz C, Wende W, Selent U, Pingoud A
Institut für Biochemie, Fachbereich Biologie, Justus-Liebig-Universität, Giessen, Germany.
Trends Biotechnol. 1996 Jul;14(7):235-8. doi: 10.1016/0167-7799(96)10030-5.
Restriction endonucleases cleave DNA with remarkable sequence specificity. In this review, we summarize the status of, and prospects for, engineering restriction endonucleases with new specificities. Such variants could be of considerable commercial value because restriction enzymes are among the most frequently used enzymes in molecular biology, and not all the desirable specificities are available. While it has not yet been possible to effect specificity changes, mutant have been described that (1) exhibit relaxed specificity, (2) favour modified substrates over their natural substrates, (3) discriminate between cleavage sites located in different sequences, (4) prefer metal ions other than Mg2+ as cofactors for cleavage, or (5) possess site-specific DNA-nicking activity.
限制性内切核酸酶能以极高的序列特异性切割DNA。在本综述中，我们总结了工程改造具有新特异性的限制性内切核酸酶的现状与前景。此类变体可能具有相当大的商业价值，因为限制性酶是分子生物学中使用最频繁的酶之一，而且并非所有理想的特异性都有现成的。虽然目前还无法实现特异性的改变，但已报道的突变体具有以下特点：（1）表现出宽松的特异性；（2）相较于天然底物，更倾向于修饰后的底物；（3）能区分位于不同序列中的切割位点；（4）切割时更偏好Mg2+以外的金属离子作为辅因子；或（5）具有位点特异性DNA切口活性。
