Archaeal MutS5 tightly binds to Holliday junction similarly to eukaryotic MutSγ
Archaeal MutS5 tightly binds to Holliday junction similarly to eukaryotic MutSγ
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古菌 MutS5 与霍利迪连接体紧密结合，类似于真核 MutSγ
DOI：
10.1111/febs.14204
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Wakamatsu Taisuke
中科院分区：
文献类型：
--
作者：
Ohshita Koki;Fukui Kenji;Sato Mizuki;Morisawa Takashi;Hakumai Yuichi;Morono Yuki;Inagaki Fumio;Yano Takato;Ashiuchi Makoto;Wakamatsu Taisuke
其DNA重组机制及相关蛋白与真核生物相似。然而，在古细菌中还没有鉴定出真核MutSγ的功能同源物，其识别Holliday连接以促进同源重组。因此，古细菌同源重组的整个分子机制尚未被揭示。在这项研究中，为了鉴定MutSγ的古生物功能同源物，我们将重点放在一个功能不明的MutS同源物MutS5上，该同源物来自超嗜热古细菌Pyrococcus horikoshii（phMutS5）。大肠杆菌MutS5具有含步行者ATP酶基序的氨基酸序列，该序列与MutSγ的ATP酶结构域相似。已知MutS同源物的ATP酶结构域也是二聚化结构域。化学交联显示纯化的phMutS5具有在溶液中二聚化的能力。phMutS5以比其他分支和线性DNA更高的亲和力与霍利迪连接结合，这类似于MutSγ和细菌MutS2（霍利迪连接解析MutS同源物）的DNA结合特异性。然而，与MutS2不同，phMutS5对分支DNA没有核酸酶活性。与MutSγ相似，Holliday连接的存在显著地刺激了phMutS 5的ATP酶活性。此外，定点突变显示ATP酶活性依赖于蛋白质的步行者ATP酶基序。这些结果表明，古细菌MutS5应该稳定Holliday连接并在同源重组中发挥作用，这与真核MutSγ的功能类似。
Archaeal DNA recombination mechanism and the related proteins are similar to those in eukaryotes. However, no functional homolog of eukaryotic MutSγ, which recognizes Holliday junction to promote homologous recombination, has been identified in archaea. Hence, the whole molecular mechanism of archaeal homologous recombination has not yet been revealed. In this study, to identify the archaeal functional homolog of MutSγ, we focused on a functionally uncharacterized MutS homolog, MutS5, from a hyperthermophilic archaeonPyrococcus horikoshii(phMutS5). Archaeal MutS5 has a Walker ATPase motif‐containing amino acid sequence that shows similarity to the ATPase domain of MutSγ. It is known that the ATPase domain of MutS homologs is also a dimerization domain. Chemical cross‐linking revealed that purified phMutS5 has an ability to dimerize in solution. phMutS5 bound to Holliday junction with a higher affinity than to other branched and linear DNAs, which resembles the DNA‐binding specificities of MutSγ and bacterial MutS2, a Holliday junction‐resolving MutS homolog. However, phMutS5 has no nuclease activity against branched DNA unlike MutS2. The ATPase activity of phMutS5 was significantly stimulated by the presence of Holliday junction similarly to MutSγ. Furthermore, site‐directed mutagenesis revealed that the ATPase activity is dependent on the Walker ATPase motif of the protein. These results suggest that archaeal MutS5 should stabilize the Holliday junction and play a role in homologous recombination, which is analogous to the function of eukaryotic MutSγ.
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影响因子：
2.9
作者：
KURAMITSU, S;HIROMI, K;KAGAMIYAMA, H
通讯作者：
KAGAMIYAMA, H
影响因子：
2.6
作者：
R. Vijayvargia;I. Biswas
通讯作者：
R. Vijayvargia;I. Biswas
影响因子：
4.8
作者：
Dufner, P;Marra, G;Jiricny, J
通讯作者：
Jiricny, J
DOI：
10.1016/j.bbapap.2017.06.024
发表时间：
2017-09-01
影响因子：
3.2
作者：
Fukui, Kenji;Iino, Hitoshi;Yano, Takato
通讯作者：
Yano, Takato
影响因子：
4.8
作者：
Iaccarino, I;Marra, G;Jiricny, J
通讯作者：
Jiricny, J