文章基本信息

标题：Remodeling the conformational dynamics of I-motif DNA by helicases in ATP-independent mode at acidic environment
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作者：Bo Gao ; Ya-Ting Zheng ; Ai-Min Su 等
期刊名称：iScience
印刷版ISSN：2589-0042
出版年度：2022
卷号：25
期号：1
页码：1-18
DOI：10.1016/j.isci.2021.103575
语种：English
出版社：Elsevier
摘要：SummaryI-motifs are noncanonical four-stranded DNA structures formed by C-rich sequences at acidic environment with critical biofunctions. The particular pH sensitivity has inspired the development of i-motifs as pH sensors and DNA motors in nanotechnology. However, the folding and regulation mechanisms of i-motifs remain elusive. Here, using single-molecule FRET, we first show that i-motifs are more dynamic than G4s. Impressively, i-motifs display a high diversity of six folding species with slow interconversion. Further results indicate that i-motifs can be linearized by Replication protein A. More importantly, we identified a number of helicases with high specificity to i-motifs at low pH. All these helicases directly act on and efficiently resolve i-motifs into intermediates independent of ATP, although they poorly unwind G4 or duplex at low pH. Owing to the extreme sensitivity to helicases and no need for ATP, i-motif may be applied as a probe for helicase sensing bothin vitroandin vivo.Graphical abstractDisplay OmittedHighlights•I-motifs display a high diversity of six folding species with slow interconversion•Replication protein A efficiently linearizes i-motifs at acidic pH•Helicases specifically bind to and unfold i-motifs at acidic pH independent of ATP•I-motif can be used as a convenient probe for helicase sensingin vitroBiological sciences; Biochemistry; Molecular biology; Structural biology