Mechanical characterization of actomyosin complex by molecular mechanics simulations.

PURPOSE

Knowledge of the mechanical behavior of myosin and actin monomer is critical for understanding the molecular mechanism of actomyosin-based muscle and non-muscle motility. Different experimental studies concerning actomyosin interaction have been performed in vitro, but studies at the single molecule level have just begun. The aim of this study was to provide a mechanical characterization of myosin II and actin monomer using a numerical approach.

METHODS

The elastic properties of the two proteins involved in muscle contraction were assessed by performing stretching simulations up to 10% protein elongation using the restraining method. Interaction properties of the actomyosin complex were evaluated at eight intermolecular distances during which the entire system was left free to move.

RESULTS

According to our results, the values of the elastic modulus of the myosin motor domain and actin are 0.30 GPa, and 0.08 GPa, respectively. As for the actomyosin complex, the interaction force has a maximum value of 541.15 pN.

CONCLUSIONS

Mechanical properties of molecular motors are currently being debated. Our results match a number of experimental data, therefore, supporting the idea that molecular mechanics may be a powerful tool to find a way in this complex subject.