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Probing DNA conformational changes with high temporal resolution by tethered particle motion.
Manoel Manghi1, Catherine Tardin, Julien Baglio
1Université de Toulouse, UPS, Laboratoire de Physique Théorique (IRSAMC), F-31062 Toulouse, France. CNRS, F-31062 Toulouse, France.
Physical Biology
|October 19, 2010
Summary
Tethered particle motion (TPM) tracks DNA dynamics by observing particle movement. Researchers calibrated TPM, finding optimal resolution down to 20 ms by minimizing particle-DNA friction with smaller probes.
Area of Science:
- Biophysics
- Molecular Biology
- Nanotechnology
Background:
- Tethered particle motion (TPM) tracks DNA conformational changes like looping and protein interactions.
- TPM relies on monitoring a particle probe's Brownian motion, tethered by a DNA molecule to a surface.
Purpose of the Study:
- To calibrate the time resolution of TPM based on dynamical properties.
- To analyze how DNA relaxation time is influenced by DNA length and particle size.
Main Methods:
- Comparative analysis of theoretical models, computer simulations, and experimental data.
- Measurement of relaxation times for DNA lengths from 401 to 2080 base pairs.
- Investigation using particle radii ranging from 20 to 150 nm.
Main Results:
- The relaxation time of the particle-DNA complex increases with DNA contour length and particle radius.
- For particles ≤ 20 nm radius, hydrodynamic friction from the particle and surface minimally impacts DNA dynamics.
- Optimal TPM time resolution can achieve 20 ms in specific experimental setups.
Conclusions:
- A dynamical calibration of TPM is proposed, linking relaxation time to system parameters.
- Minimizing particle size is key to achieving high time resolution in TPM experiments.
- TPM offers a powerful tool for studying DNA conformational dynamics with millisecond precision.
