Single-molecule studies reveal reciprocating of WRN helicase core along ssDNA during DNA unwinding.
Single-molecule studies reveal reciprocating of WRN helicase core along ssDNA during DNA unwinding.
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单分子研究揭示了 DNA 解旋过程中 WRN 解旋酶核心沿着 ssDNA 往复运动
DOI：
10.1038/srep43954
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发表时间：
2017-03-07
影响因子：
4.6
通讯作者：
Xi XG
中科院分区：
文献类型：
--
作者：
Wu WQ;Hou XM;Zhang B;Fossé P;René B;Mauffret O;Li M;Dou SX;Xi XG
沃纳综合征是由编码WRN解旋酶的WRN基因突变引起的。了解WRN解旋酶的体外解旋机制有助于预测其在体内的行为，进而了解其生物学功能。为了深入理解WRN的DNA解旋机制，本研究利用单分子荧光共振能量转移（smFRET）方法，对鸡WRN解旋酶核心的DNA解旋特性进行了详细的表征。我们发现WRN在不同的DNA结构上表现出重复的DNA解旋和易位行为，包括分叉的，悬垂的和含有G-四链体的DNA，具有明显有限的解旋持续性。进一步揭示了重复行为是由WRN沿着相同ssDNA的往复运动引起的，而不是由与底物的完全解离和重新结合或链转换引起的。本研究揭示了新的光WRN的运作机制。
Werner syndrome is caused by mutations in the WRN gene encoding WRN helicase. A knowledge of WRN helicase’s DNA unwinding mechanism in vitro is helpful for predicting its behaviors in vivo, and then understanding their biological functions. In the present study, for deeply understanding the DNA unwinding mechanism of WRN, we comprehensively characterized the DNA unwinding properties of chicken WRN helicase core in details, by taking advantages of single-molecule fluorescence resonance energy transfer (smFRET) method. We showed that WRN exhibits repetitive DNA unwinding and translocation behaviors on different DNA structures, including forked, overhanging and G-quadruplex-containing DNAs with an apparently limited unwinding processivity. It was further revealed that the repetitive behaviors were caused by reciprocating of WRN along the same ssDNA, rather than by complete dissociation from and rebinding to substrates or by strand switching. The present study sheds new light on the mechanism for WRN functioning.