Single-molecule kinetic locking allows fluorescence-free quantification of protein/nucleic-acid binding

Area of Science:

• Biophysics
• Molecular Biology
• Biochemistry

Background:

• Fluorescence-free micro-manipulation of nucleic acids (NA) is crucial for studying DNA/RNA processing proteins.
• Current methods lack the ability to detect and quantify protein binding without label interference.

Purpose of the Study:

• To develop a novel method for direct in vitro visualization and quantification of protein binding to NA.
• To overcome the limitations of existing fluorescence-free techniques in detecting protein-NA interactions.

Main Methods:

• Development of a single-molecule force spectroscopy technique called kinetic locking.
• Validation of kinetic locking by measuring hybridization energy of short nucleotides (5-7 bases).
• Application of kinetic locking to study Escherichia coli RecQ helicase dynamics with its DNA substrate.

Main Results:

• Kinetic locking enables direct visualization of protein binding to NA without chemical disturbance.
• Accurate measurement of hybridization energy for ultrashort nucleotides was achieved.
• Dynamical interactions between E. coli RecQ helicase and its DNA substrate were successfully measured.

Conclusions:

• Kinetic locking is a powerful tool for functional characterization of NA-binding proteins.
• This method provides label-free, in vitro insights into protein-nucleic acid interactions.
• The technique advances the study of DNA/RNA processing proteins and their dynamics.