Does Changing the Pulling Direction Give Better Insight into Biomolecules?

Abstract

Single-molecule manipulation techniques reveal that the mechanical resistance of a protein depends on the direction of the applied force. Using a lattice model of polymers, we show that changing the pulling direction leads to different phase diagrams. The simple model proposed here indicates that in one case the system undergoes a transition akin to the unzipping of a beta sheet, while in the other case the transition is of a shearing (slippage) nature. Our results are qualitatively similar to experimental results. This demonstrates the importance of varying the pulling direction since this may yield enhanced insights into the molecular interactions responsible for the stability of biomolecules.