Structural and functional studies of SF1B Pif1 from Thermus oshimai reveal dimerization-induced helicase inhibition.
Structural and functional studies of SF1B Pif1 from Thermus oshimai reveal dimerization-induced helicase inhibition.
复制标题
来自 Thermus oshimai 的 SF1B Pif1 的结构和功能研究揭示了二聚化诱导的解旋酶抑制
DOI：
10.1093/nar/gkab188
复制
发表时间：
2021-04-19
影响因子：
14.9
通讯作者：
Xi XG
中科院分区：
文献类型：
--
作者：
Dai YX;Chen WF;Liu NN;Teng FY;Guo HL;Hou XM;Dou SX;Rety S;Xi XG
摘要Pif 1是一种SF 1B解旋酶，从细菌到人类都是进化上保守的，在维持细胞核和线粒体基因组稳定性方面起着多种作用。Pif 1家族虽然高度保守，但其机制多样性很大。在这里，我们报告的晶体结构Thermus oshimai Pif 1（ToPif 1）单独和复杂的部分双链或单链DNA。在载脂蛋白状态和与部分双链体DNA的复合物中，ToPif 1是单体的，其结构域2B/loop 3分别采用闭合和开放构象。当与单链DNA复合时，ToPif 1形成稳定的二聚体，结构域2B/loop 3转变为更开放的构象。单分子和生物化学分析表明，域2B/loop 3开关之间的封闭和开放的构象时，ToPif 1单体解旋DNA和，与其他典型的二聚体SF 1A解旋酶，二聚化有抑制作用，其解旋酶的活性。这一机制并不适用于所有Pif 1解旋酶，但说明了不同解旋酶之间调节机制的多样性。这也提出了这样的可能性，即虽然二聚化导致SF 1A解旋酶的激活，但它可能导致对一些其他未表征的SF 1B解旋酶的抑制，这是一个值得进一步研究的有趣主题。
Abstract Pif1 is an SF1B helicase that is evolutionarily conserved from bacteria to humans and plays multiple roles in maintaining genome stability in both nucleus and mitochondria. Though highly conserved, Pif1 family harbors a large mechanistic diversity. Here, we report crystal structures of Thermus oshimai Pif1 (ToPif1) alone and complexed with partial duplex or single-stranded DNA. In the apo state and in complex with a partial duplex DNA, ToPif1 is monomeric with its domain 2B/loop3 adopting a closed and an open conformation, respectively. When complexed with a single-stranded DNA, ToPif1 forms a stable dimer with domain 2B/loop3 shifting to a more open conformation. Single-molecule and biochemical assays show that domain 2B/loop3 switches repetitively between the closed and open conformations when a ToPif1 monomer unwinds DNA and, in contrast with other typical dimeric SF1A helicases, dimerization has an inhibitory effect on its helicase activity. This mechanism is not general for all Pif1 helicases but illustrates the diversity of regulation mechanisms among different helicases. It also raises the possibility that although dimerization results in activation for SF1A helicases, it may lead to inhibition for some of the other uncharacterized SF1B helicases, an interesting subject warranting further studies.
登录
查看更多内容
影响因子：
3.8
作者：
Bochman ML;Sabouri N;Zakian VA
通讯作者：
Zakian VA
影响因子：
6.1
作者：
Brookes E;Vachette P;Rocco M;Pérez J
通讯作者：
Pérez J
影响因子：
14.9
作者：
Yuan F;Griffin L;Phelps L;Buschmann V;Weston K;Greenbaum NL
通讯作者：
Greenbaum NL
影响因子：
2.9
作者：
Andis, Nicholas M.;Sausen, Christopher W.;Bochman, Matthew L.
通讯作者：
Bochman, Matthew L.
影响因子：
5.6
作者：
Cheng, W;Hsieh, J;Lohman, TM
通讯作者：
Lohman, TM