Heitman J
Rockefeller University, New York, NY 10021.
Bioessays. 1992 Jul;14(7):445-54. doi: 10.1002/bies.950140704.
One popular recombinant DNA tool is the EcoRI endonuclease, which cleaves DNA at GAATTC sites and serves as a paradigm for sequence specific DNA-enzyme interactions. The recently revised X-ray crystal structure of an EcoRI-DNA complex reveals EcoRI employs novel DNA recognition motifs, a four alpha-helix bundle and two extended chains, which project into the major groove to contact substrate purines and pyrimidines. Interestingly, pyrimidine contacts had been predicted based on genetic and biochemical studies. Current work focuses on the EcoRI active site structure, enzyme and substrate conformational changes during catalysis, and host-restriction system interactions.
一种常用的重组DNA工具是EcoRI核酸内切酶，它在GAATTC位点切割DNA，并作为序列特异性DNA-酶相互作用的范例。最近修订的EcoRI-DNA复合物的X射线晶体结构表明，EcoRI采用了新颖的DNA识别基序，即一个四α-螺旋束和两条延伸链，它们伸入大沟以接触底物嘌呤和嘧啶。有趣的是，基于遗传学和生物化学研究已经预测到了嘧啶接触。当前的工作集中在EcoRI活性位点结构、催化过程中酶和底物的构象变化以及宿主限制系统相互作用。
