限制性内切酶BamHI的结构及其与EcoRI的关系。

Structure of restriction endonuclease BamHI and its relationship to EcoRI.

作者信息

Newman M, Strzelecka T, Dorner L F, Schildkraut I, Aggarwal A K

机构信息

Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032.

出版信息

Nature. 1994 Apr 14;368(6472):660-4. doi: 10.1038/368660a0.

DOI:10.1038/368660a0

PMID:8145855

Abstract

Type II restriction endonucleases are characterized by the remarkable specificity with which they cleave specific DNA sequences. Surprisingly, their protein sequences are in most cases unrelated, and no recurring structural motif has yet been identified. We have determined the structure of restriction endonuclease BamHI at 1.95 A resolution. BamHI shows striking resemblance to the structure of endonuclease EcoRI (refs 3, 4), despite the lack of sequence similarity between them. We also observe some curious differences between the two structures, and propose an evolutionary scheme that may explain them. The active site of BamHI is structurally similar to the active sites of EcoRI and EcoRV (ref. 5), but the mechanism by which BamHI activates a water molecule for nucleophilic attack may be different.

摘要

II型限制性核酸内切酶的特点是能以极高的特异性切割特定的DNA序列。令人惊讶的是，它们的蛋白质序列在大多数情况下并无关联，且尚未发现反复出现的结构基序。我们已确定了限制性核酸内切酶BamHI在1.95埃分辨率下的结构。尽管BamHI与核酸内切酶EcoRI之间缺乏序列相似性，但它与EcoRI的结构却惊人地相似。我们还观察到这两种结构之间存在一些奇特的差异，并提出了一种可能解释这些差异的进化方案。BamHI的活性位点在结构上与EcoRI和EcoRV的活性位点相似，但BamHI激活水分子进行亲核攻击的机制可能有所不同。