Single-molecule mechanical fingerprinting with DNA nanoswitch calipers

Area of Science:

• Biotechnology
• Nanotechnology
• Biophysics

Background:

• Identifying biomolecules in trace samples is crucial but challenging for proteins due to complexity and lack of amplification.
• Existing methods like mass spectrometry have limitations in single-molecule protein identification.

Purpose of the Study:

• To develop a novel tool for precise, single-molecule analysis of biomolecules, particularly proteins.
• To overcome limitations in current protein identification techniques by enabling atomic-level measurements.

Main Methods:

• Combined DNA nanotechnology with single-molecule force spectroscopy.
• Utilized optical tweezers for absolute distance measurements with ångström-level precision.
• Employed multiplexed magnetic tweezers for quantifying relative abundance in mixed samples.

Main Results:

• Demonstrated ångström-level precision distance measurements for DNA and peptides.
• Achieved single-molecule fingerprinting of peptides by measuring distances between DNA-labeled residues.
• Successfully discriminated between different post-translational modifications in heterogeneous peptide populations.

Conclusions:

• DNA nanoswitch calipers offer a powerful and accessible method for characterizing nanoscale complexes.
• This technology enables precise distance measurements, advancing single-molecule proteomics.
• The tool facilitates new applications in biomolecular identification and characterization.