Remodeling the conformational dynamics of I-motif DNA by helicases in ATP-independent mode at acidic environment

Autor: Bo Gao, Ya-Ting Zheng, Ai-Min Su, Bo Sun, Xu-Guang Xi, Xi-Miao Hou
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: iScience, Vol 25, Iss 1, Pp 103575- (2022)
Druh dokumentu: article
ISSN: 2589-0042
DOI: 10.1016/j.isci.2021.103575
Popis: Summary: I-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 both in vitro and in vivo.
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