Holliday junction resolving enzymes of archaeal viruses SIRV1 and SIRV2
Holliday junction resolving enzymes of archaeal viruses SIRV1 and SIRV2
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DOI：
10.1006/jmbi.2001.4761
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发表时间：
2001-06-22
影响因子：
5.6
通讯作者：
Kemper, B
中科院分区：
文献类型：
--
作者：
Birkenbihl, RP;Neef, K;Kemper, B
在基因重组的最后阶段，Holliday连接分解酶通过在连接两侧引入一对交错的缺口，将四向DNA中间转化为两个双工DNA分子。这一基本过程显然是来自所有三个生命领域的细胞所共有的。两种细胞分解酶来自古细菌领域两个王国的极端嗜热代表，euryarchaeon Pyrococcus furiosus和crenarchaeon Sulfolobus solfataricus，最近被描述。本文首次从两种古细菌中分离纯化了Holliday结切割酶（Hjc），并对其进行了鉴定。SIRV1和SIRV2这两种病毒都能感染岛盲蝽。它们的Hjcs都由121个氨基酸残基（aa）组成，仅相差18个氨基酸残基。两种蛋白选择性结合合成的holliday结构类似物，表观解离常数为25 nM。在Mg2+存在下，酶在结附近产生相同的切割模式。重组SIRV2 Hjc在45 ~ 70°c之间的溶核活性最高，而S. islandicus在80°c左右生长最佳。基于它们对四向DNA结构的特异性，这些酶可能在遗传重组、DNA修复和复制中间体的分解中发挥普遍作用。(C) 2001学术出版社。
In the final stages of genetic recombination, Holliday junction resolving enzymes transform the four-way DNA intermediate into two duplex DNA molecules by introducing pairs of staggered nicks flanking the junction. This fundamental process is apparently common to cells from all three domains of life. Two cellular resolving enzymes from extremely thermophilic representatives of both kingdoms of the domain Archaea, the euryarchaeon Pyrococcus furiosus and the crenarchaeon Sulfolobus solfataricus, have been described recently. Here we report for the first time the isolation, purification and characterization of Holliday junction cleaving enzymes (Hjc) from two archaeal viruses. Both viruses, SIRV1 and SIRV2, infect Sulfolobus islandicus. Their Hjcs both consist of 121 amino acid residues (aa) differing only by 18 aa. Both proteins bind selectively to synthetic Holliday-structure analogues with an apparent dissociation constant of 25 nM. In the presence of Mg2+ the enzymes produce identical cleavage patterns near the junction. While S. islandicus shows optimal growth at about 80 degreesC, the nucleolytic activities of recombinant SIRV2 Hjc was highest between 45 degreesC and 70 degreesC. Based on their specificity for four-way DNA structures the enzymes may play a general role in genetic recombination, DNA repair and the resolution of replicative intermediates. (C) 2001 Academic Press.