Structure of the tetrameric restriction endonuclease NgoMIV in complex with cleaved DNA
Structure of the tetrameric restriction endonuclease NgoMIV in complex with cleaved DNA
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DOI：
10.1038/79032
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发表时间：
2000-09-01
期刊：
影响因子：
--
通讯作者：
Huber, R
中科院分区：
文献类型：
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作者：
Deibert, M;Grazulis, S;Huber, R
在1.6埃分辨率下测定了NgoMIV限制性内切酶与裂解DNA复合物的晶体结构。晶体不对称单元包含一个蛋白质四聚体和两个在其识别位点切割的DNA分子。这是四聚限制性内切酶- dna复合物的第一个结构。在四聚体中，两个初级二聚体背对背排列，两个寡核苷酸在四聚体的相对两侧以裂缝结合。DNA分子保持b型构象，它们的螺旋轴之间有一个60度的封闭角。序列特定的相互作用发生在主要和次要凹槽中。两个Mg2+离子位于NgoMIV活性位点裂解磷酸盐附近。生化实验表明，四聚体内识别位点之间的相互作用大大提高了DNA的切割效率。
The crystal structure of the NgoMIV restriction endonuclease in complex with cleaved DNA has been determined at 1.6 Angstrom resolution. The crystallographic asymmetric unit contains a protein tetramer and two DNA molecules cleaved at their recognition sites. This is the first structure of a tetrameric restriction enzyme-DNA complex. In the tetramer, two primary dimers are arranged back to back with two oligonucleotides bound in clefts on opposite sides of the tetramer. The DNA molecules retain a B-type conformation and have an enclosed angle between their helical axes of 60 degrees. Sequence-specific interactions occur in both the major and minor grooves. Two Mg2+ ions are located close to the cleaved phosphate at the active site of NgoMIV. Biochemical experiments show that interactions between the recognition sites within the tetramer greatly increase DNA cleavage efficiency.