Single-Molecule FRET Analysis of Replicative Helicases

Area of Science:

• Biochemistry and Molecular Biology
• Biophysics

Background:

• Helicase activity is crucial for DNA replication and other DNA metabolic processes.
• Understanding helicase mechanisms requires high-resolution techniques to observe dynamic behavior.

Purpose of the Study:

• To detail single-molecule fluorescence resonance energy transfer (smFRET) assays for studying helicase DNA unwinding and dynamics.
• To apply smFRET to investigate coordination of DNA replication and specific helicase behaviors.

Main Methods:

• Utilizing single-molecule fluorescence resonance energy transfer (smFRET) to monitor biomolecular behavior at the nanoscale.
• Developing and applying smFRET assays to probe DNA unwinding by replicative helicases.

Main Results:

• smFRET successfully resolved real-time DNA unwinding steps of Bacteriophage T7 helicase.
• Observed heterogeneous unwinding patterns influenced by the E1 helicase DNA binding domain.
• Demonstrated coordination between leading and lagging strand synthesis during DNA replication.

Conclusions:

• smFRET is a powerful tool for elucidating real-time helicase mechanisms and dynamics.
• These assays are broadly applicable to various hexameric helicases, both replicative and non-replicative.