Viscoelasticity and Dynamics of Single Biopolymer Chain Measured with Magnetically Modulated Atomic Force Microscopy

Viscoelactic response of a titin single molecule chain during the course of forced unraveling was studied using atomic force microscopy. Effect of transition to/from an unfolding intermediate onto the measured elasticity data was analyzed. The result hinted that emergence of the transition onto the elasticity depends on the experimental condition such as modulation force amplitude. Anomalous slow unraveling of one domain was observed and its viscoelastic response was discussed from the viewpoint of internal friction of polymer.