Rafferty John B, Bolt Edward L, Muranova Tatyana A, Sedelnikova Svetlana E, Leonard Philip, Pasquo Alessandra, Baker Patrick J, Rice David W, Sharples Gary J, Lloyd Robert G
Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom.
Structure. 2003 Dec;11(12):1557-67. doi: 10.1016/j.str.2003.11.004.
Holliday junction resolution performed by a variety of structure-specific endonucleases is a key step in DNA recombination and repair. It is believed that all resolvases carry out their reaction chemistries in a similar fashion, utilizing a divalent cation to facilitate the hydrolysis of the phosphodiester backbone of the DNA, but their architecture varies. To date, with the exception of bacteriophage T4 endonuclease VII, each of the known resolvase enzyme structures has been categorized into one of two families: the integrases and the nucleases. We have now determined the structure of the Escherichia coli RusA Holliday junction resolvase, which reveals a fourth structural class for these enzymes. The structure suggests that dimer formation is essential for Mg(2+) cation binding and hence catalysis and that like the other resolvases, RusA distorts its Holliday junction target upon binding. Key residues identified by mutagenesis experiments are well positioned to interact with the DNA.
由多种结构特异性核酸内切酶执行的霍利迪连接体拆分是DNA重组和修复中的关键步骤。据信，所有拆分酶都以相似的方式进行其反应化学过程，利用二价阳离子促进DNA磷酸二酯主链的水解，但其结构各不相同。迄今为止，除了噬菌体T4核酸内切酶VII外，已知的每种拆分酶结构都已被归类为两个家族之一：整合酶家族和核酸酶家族。我们现已确定了大肠杆菌RusA霍利迪连接体拆分酶的结构，该结构揭示了这些酶的第四种结构类型。该结构表明二聚体形成对于Mg(2+)阳离子结合至关重要，因此对于催化也至关重要，并且与其他拆分酶一样，RusA在结合时会使其霍利迪连接体靶点发生扭曲。通过诱变实验确定的关键残基处于与DNA相互作用的有利位置。
Zotero 插件