Coarse-Grained Langevin Equation for Protein Dynamics: Global Anisotropy and a Mode Approach to Local Complexity

Area of Science:

• Biophysics
• Computational Biology
• Protein Dynamics

Background:

• Proteins are semiflexible molecules with complex dynamics.
• Accurate modeling of protein motion is crucial for understanding function.
• Existing rigid-body models lack internal dissipation, limiting their accuracy.

Purpose of the Study:

• To develop a multiscale approach for quantitative protein dynamics.
• To analytically solve protein dynamics using a coarse-grained Langevin equation.
• To incorporate internal dissipation into protein motion modeling.

Main Methods:

• Multiscale modeling: molecular dynamics (MD) simulations coupled with Langevin equation.
• Analytical normal-mode solution of the Langevin equation for protein dynamics.
• Input from MD simulations provides quantitative structural averages for the Langevin model.

Main Results:

• The model describes proteins as semiflexible objects in a folded state free energy well.
• Dynamics are separated into global anisotropic tumbling and local internal fluctuations.
• The approach quantitatively predicts dynamics from picoseconds to nanoseconds.
• Results show good agreement with MD simulations and nuclear magnetic resonance (NMR) experiments.

Conclusions:

• The multiscale approach provides a quantitative description of protein dynamics.
• It accurately captures both global and internal motions, including internal dissipation.
• This method offers a powerful tool for studying protein behavior and comparing with experimental data.