Crystal structure of the Bse634I restriction endonuclease:: comparison of two enzymes recognizing the same DNA sequence
Crystal structure of the Bse634I restriction endonuclease:: comparison of two enzymes recognizing the same DNA sequence
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DOI：
10.1093/nar/30.4.876
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发表时间：
2002-02-15
影响因子：
14.9
通讯作者：
Siksnys, V
中科院分区：
文献类型：
--
作者：
Grazulis, S;Deibert, M;Siksnys, V
11型限制性核酸内切酶的晶体结构显示出保守的共同核心和活性位点残基，但不同的结构元件参与DNA序列区分。因此，识别相同核苷酸序列的限制性内切酶的比较结构分析可能有助于我们理解限制性内切酶内特异性决定簇的结构多样性。我们已经解决了嗜热脂肪芽孢杆菌限制性内切核酸酶Bse 63411的晶体结构的多重同晶置换技术，以2.17埃的分辨率。Bse 6341是Cfr 101限制性内切酶的同分异构体，其晶体结构已在先前报道。第一对同分异构酶的比较结构分析揭示了序列识别和催化的保守结构决定因素。然而，Bse 6341/Cfr 101之间的N-末端亚结构域的构象不同，这表明可能耦合DNA识别和催化的刚体运动。结构相似性延伸到四级结构水平：晶体接触表明，Bse 6341类似于Cfr 101被安排为四聚体。动力学分析表明，Bse 6341能够同时与两个识别位点相互作用，支持蛋白质的四聚体结构。因此，识别重叠核苷酸序列的限制性内切酶Bse 6341、Cfr 101和NgoMIV表现出具有功能重要性的保守的四聚体结构。
Crystal structures of Type 11 restriction endonucleases demonstrate a conserved common core and active site residues but diverse structural elements involved in DNA sequence discrimination. Comparative structural analysis of restriction enzymes recognizing the same nucleotide sequence might therefore contribute to our understanding of the structural diversity of specificity determinants within restriction enzymes. We have solved the crystal structure of the Bacillus stearothermophilus restriction endonuclease Bse63411 by the multiple isomorphous replacement technique to 2.17 Angstrom resolution. Bse6341 is an isoschisomer of the Cfr101 restriction enzyme whose crystal structure has been reported previously. Comparative structural analysis of the first pair of isoschisomeric enzymes revealed conserved structural determinants of sequence recognition and catalysis. However, conformations of the N-terminal subdomains differed between Bse6341/Cfr101, suggesting a rigid body movement that might couple DNA recognition and catalysis. Structural similarities extend to the quaternary structure level: crystal contacts suggest that Bse6341 similarly to Cfr101 is arranged as a tetramer. Kinetic analysis reveals that Bse6341 is able to interact simultaneously with two recognition sites supporting the tetrameric architecture of the protein. Thus, restriction enzymes Bse6341, Cfr101 and NgoMIV, recognizing overlapping nucleotide sequences, exhibit a conserved tetrameric architecture that is of functional importance.