Helicase activity and substrate specificity of RecQ5β

• 来源期刊: 中国物理B（英文版）
• 关键词: helicase RecQ5β DNA substrate specificity unwinding kinetics
• 年，卷（期）: 2017,（6）
• 页码范围: 499-507
• 页数: 9页
• 语种: 英文
• DOI: 10.1088/1674-1056/26/6/068701

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/dsDNA,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 RecQ5β1-467,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.