Helicase activity and substrate specificity of RecQ5β  

作　　者：尤菁 徐雅楠 李辉 吕袭明 李伟 王鹏业 窦硕星 奚绪光 

机构地区：[1]Beijing National Laboratory for Condensed Matter Physics and CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences (CAS), Beijing 100190, China [2]School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China [3]College of Life Science, Inner Mongolia University for Nationalities, Tongliao 028000, China [4]College of Life Sciences, Northwest Agriculture and Forestry University, Yangling 712100, China [5]LBPA, IDA, ENS Cachan, CNRS, Universite Paris-Saclay, Cachan F-94235, France

出　　处：《Chinese Physics B》2017年第6期499-507,共9页中国物理B（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.11674383,11474346,and 11274374);the National Basic Research Program of China(Grant No.2013CB837200);the National Key Research and Development Program of China(Grant No.2016YFA0301500)

摘　　要：RecQ5β is an essential DNA helicase in humans, playing important roles in DNA replication, repair, recombination and transcription. The unwinding activity and substrate specificity of RecQ5β is still elusive. Here, we used stopped-flow kinetic method to measure the unwinding and dissociation kinetics of RecQ5β with several kinds of DNA substrates, and found that RecQ5β could well unwind ss/ds DNA, forked DNA and Holiday junction, but was compromised in unwinding blunt DNA and G-quadruplex. Rec5β has the preferred unwinding specificity for certain DNA substrates containing the junction point, which may improve the binding affinity and unwinding activity of RecQ5β. Moreover, from a comparison with the truncated RecQ5β～（1-467）, we discovered that the C-terminal domain might strongly influence the unwinding activity and binding affinity of RecQ5β. These results may shed light on the physiological functions and working mechanisms of RecQ5β helicase.RecQ5β is an essential DNA helicase in humans, playing important roles in DNA replication, repair, recombination and transcription. The unwinding activity and substrate specificity of RecQ5β is still elusive. Here, we used stopped-flow kinetic method to measure the unwinding and dissociation kinetics of RecQ5β with several kinds of DNA substrates, and found that RecQ5β could well unwind ss/ds DNA, forked DNA and Holiday junction, but was compromised in unwinding blunt DNA and G-quadruplex. Rec5β has the preferred unwinding specificity for certain DNA substrates containing the junction point, which may improve the binding affinity and unwinding activity of RecQ5β. Moreover, from a comparison with the truncated RecQ5β～（1-467）, we discovered that the C-terminal domain might strongly influence the unwinding activity and binding affinity of RecQ5β. These results may shed light on the physiological functions and working mechanisms of RecQ5β helicase.

关 键 词：HELICASE RecQ5β DNA substrate specificity unwinding kinetics 

分 类 号：Q75[生物学—分子生物学]