Power Strokes in Molecular Motors: Predictive, Irrelevant, or Somewhere in Between?

Area of Science:

• Biophysics
• Chemical Engineering
• Computational Biology

Background:

• The power stroke mechanism, analogous to macroscopic engines, has long been used to explain molecular motor directionality.
• Despite evidence of its limitations, this intuition persists in some scientific communities.

Purpose of the Study:

• To systematically investigate how molecular motor directionality responds to modifications based on power stroke intuition.
• To explore the role of conformational stability in determining motor directional bias.

Main Methods:

• Development of a catalysis-driven molecular motor model.
• Conducting simulated numerical experiments to analyze motor behavior under modified conditions.

Main Results:

• Confirmed that the power stroke mechanism generally fails to predict molecular motor directionality.
• Demonstrated that the relative stability of molecular conformations is a key factor in adjusting motor directional bias.
• Observed that attempts to alter power strokes can have side effects that influence motor bias, potentially mimicking power stroke predictions.

Conclusions:

• The power stroke mechanism is formally unimportant for determining molecular motor directionality.
• Conformational stability offers a viable design element for tuning motor directional bias.
• The apparent utility of the flawed power stroke mechanism in engineering may stem from side effects of power stroke modifications that coincidentally alter bias.