Protein imaging. Single-protein spin resonance spectroscopy under ambient conditions

Area of Science:

• Biophysics
• Quantum Sensing
• Structural Biology

Background:

• Magnetic resonance techniques are crucial for understanding biomolecular structure and dynamics.
• Measuring magnetic resonance spectra from single biomolecules has been a significant challenge in biophysics.

Purpose of the Study:

• To demonstrate the detection of electron spin resonance (ESR) signals from a single spin-labeled protein.
• To utilize a single nitrogen-vacancy (NV) center in diamond as a sensor for biomolecular measurements.
• To explore the potential for probing protein motion and enabling advanced structural analyses.

Main Methods:

• Employing a single NV center in diamond as a nanoscale sensor placed in close proximity to a single spin-labeled protein.
• Detecting the ESR signal from the spin label on the protein under ambient conditions.
• Coherently driving the spin of the label to explore its dynamics and potential for spin manipulation.

Main Results:

• Successfully detected the ESR signal from a single spin-labeled protein.
• Measured the orientation of the spin label attached to the protein.
• Observed the influence of protein motion on the spin label's dynamics.
• Demonstrated coherent spin manipulation of the label.

Conclusions:

• Single NV centers in diamond can serve as sensitive probes for single-molecule biophysics.
• This technique allows for the study of protein dynamics and orientation at the single-molecule level.
• Coherent spin control opens avenues for future applications in nuclear spin polarization and detailed protein structure analysis.