Title: Detection and Manipulation of Single Biomolecular Machines

Speaker： Dr. Shixin Liu

             Assistant Professor，Head of the Laboratory of Nanoscale Biophysics and Biochemistry，The Rockefeller University

Time： 1:00pm June 8th 2015

Address： Rm 101, East wing of Old Chemistry Building, Peking Unversity 

Chair：  Dr. Ping Wei,  Center for Quantitative Biology 

Abstract：

        After twenty-five years of development, single-molecule techniques have become popular tools to study biology. There are two broad families of single-molecule approaches: fluorescence-based detection and force-based manipulation. I will present two systems to demonstrate the power of these approaches in dissecting the molecular mechanism of complex biological processes. First, optical trapping experiments showed that a bacteriophage genome packaging motor simultaneously rotates and translocates the DNA genome during the viral life cycle. This homomeric ring ATPase displays a remarkable level of coordination and an unexpected division of labor among its subunits. As DNA is packed into the viral capsid and the internal pressure rises, the motor gradually changes its step size and the amount of DNA rotation in order to achieve robust and efficient packaging. Second, single-molecule FRET assays revealed that the HIV reverse transcriptase is able to flip and slide on nucleic acid substrates. These large-scale motions allow the enzyme to quickly switch between various binding modes and perform different functions.