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Thermal Motion of DNA in an MspA Pore

Bo Lu1, Stephen Fleming1, Tamas Szalay2

  • 1Department of Physics, Harvard University, Cambridge, Massachusetts.

Biophysical Journal
|October 8, 2015
PubMed

Insights

We studied DNA motion in nanopores to understand DNA sequencing. Increasing electric force reduces DNA

Area of Science:

  • Biophysics
  • Nanotechnology
  • Molecular Biology

Background:

  • Nanopore sequencing utilizes biological pores to analyze DNA molecules.
  • Understanding the dynamics of DNA within nanopores is crucial for optimizing sequencing accuracy and speed.

Purpose of the Study:

  • To determine the thermal motion of a DNA-NeutrAvidin complex within a Mycobacterium smegmatis porin A nanopore.
  • To investigate the relationship between electric force, diffusion, and DNA position fluctuations.
  • To provide insights into improving nanopore sequencing technologies.

Main Methods:

  • Experimental measurements of a voltage-clamped DNA-NeutrAvidin complex.
  • Computational calculations to determine electric force and diffusion constants.
  • Analysis of thermal position fluctuations within the nanopore.

Main Results:

  • The electric force and diffusion constant of DNA inside the nanopore were determined.
  • Out-of-equilibrium states rapidly return to equilibrium, leading to measurements averaging over equilibrium distributions.
  • This averaging is consistent with current nanopore sequencing experimental results.

Conclusions:

  • Thermal position fluctuations of DNA in nanopores can be reduced by increasing electrophoretic force.
  • Findings support the optimization of nanopore sequencing devices for enhanced performance.
  • The study clarifies the behavior of DNA dynamics in nanopores relevant to sequencing applications.

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