Investigation of conformation transition of interface-adsorption proteins by surface stress detecting using micro-cantilever

• 1、CAS Key laboratory of mechanical behavior and design of material, University of Science and

Abstract： A new method based on micro-cantilever sensors was presented and used to investigate conformational transition of interface-adsorption proteins. Lysozyme molecules were grafted onto one surface of a micro-cantilever by self assemble monolayer method. Then the micro-cantilever was immersed into PBS buffer solution. The deflection of the micro-cantilever was measured using optical lever technique. The results show that the micro-cantilever deflects when PBS buffer solution was replace by guanidine hydrochloride solution(6M/L)．This deflection was driven by the changes of the surface stress on the micro-cantilever surface and corresponding to the process of conformation changes of the interface-adsorption lysozyme molecule from a compact globule to a random coil. Subsequently, an opposite deflection occurs while using PBS buffer solution to replace guanidine hydrochloride solution. This phenomena was attributed to conformation reverting, i.e., from a random coil to a compact globule. The ability to extract the mechanical information during the conformation transition of the interface-adsorption proteins is a particular characteristic of this method, because it offers us a new viewpoint to understand the mechanism of conformation folding of interface-adsorption proteins.

Keywords： conformation transition； Lysozyme； surface stress； micro-cantilever