Biomechanics of actin filaments: a computational multi-level study

Area of Science:

• Biophysics
• Computational Biology
• Molecular Biology

Background:

• Actin microfilaments (F-actin) are crucial for cell mechanics.
• The relationship between F-actin's mechanical behavior and its molecular architecture is not fully understood.

Purpose of the Study:

• To computationally investigate the biomechanics of F-actin.
• To correlate F-actin mechanical properties with the molecular topology of G-actin monomers.

Main Methods:

• A multi-level computational approach combining equilibrium molecular dynamics (MD) simulations and normal mode analysis (NMA).
• Modeling and characterization of F-actins up to 500 nm in length.
• Analysis of G-actin molecular rearrangements and F-actin vibrational modes.

Main Results:

• F-actin bending stiffness, modulus, and persistence length are independent of filament length.
• The flexibility of F-actin is primarily determined by the orientations and motions of specific G-actin residue groups.

Conclusions:

• A combined MD and NMA approach effectively investigates F-actin biomechanics by considering G-actin molecular conformations.
• This computational method utilizes crystallographic G-actin data without requiring experimental parameters or residue reduction.