Macromolecular Crowding Affects Stability Properties: A Comparison Study For Titin And Ubiquitin

Abstract

Macromolecules can occupy a large fraction of the volume of the cell and this affects many properties of the proteins inside the cell, such as thermal stability and rates of folding. We present a comparison of the effects of molecular crowding in ubiquitin and titin. We have used an atomic force microscope based single molecule method to measure the effects of macromolecular crowding on the mechanical stability of these proteins. We used dextran as the crowding agent with two different molecular weights, with concentrations varying from zero to 300 grams per liter in the buffer solution. The results show that the forces that are required to unfold molecules are enhanced when high concentration of dextran molecules is added to the buffer solution.