DNA and Chromosomes
A Parallel Quadruplex DNA Is Bound Tightly but Unfolded Slowly by Pif1 Helicase
Background: Some G-rich sequences fold into intramolecular quadruplex structures. Pif1 helicase reduces genomic instability by unfolding quadruplex DNA.Results: Pif1 unfolds a parallel quadruplex structure slowly relative to unwinding of duplex DNA.Conclusion: Comparison of duplex unwinding to quadruplex unfolding is complicated by distinct kinetic mechanisms.Significance: A highly stable, intramolecular quadruplex is a formidable obstacle but can be overcome by Pif1 helicase.
