Abstract

Single-molecule manipulation of biological molecules opens a new door for a close-up investigation of the complexbiological interactions. Nanomanipulation tools such as atomic force microscope and optical tweezers are used topull single molecules while monitoring their force response. Using the recently derived nonequilibrium work theorem, i.e., Jarzynski’s equality, we were able to determine the equilibrium properties from these nonequilibrium measurements results. I will describe the free energy reconstruction and velocity dependence of titin I27 stretching and unfolding using Jarzynski’s equality. The results and implication of properties determined by mechanical manipulation of single-molecules will be discussed. Finally, I will present single-molecule studies of biological systems such as mechanical melting of DNA and protein folding, and discuss the implications and challenges as well as the significance of single-molecule manipulation in biological functions.