Mechanical measurement of the unfolding of a protein
Center for Chaos and Turbulence Studies, Niels Bohr Institute,
Blegdamsvej 17, 2100 Copenhagen Ø, Denmark
Accepted: 12 July 1996
We report the first mechanical measurement of the reversible unfolding of protein molecules. The molecules are confined between a flat plate and a sphere, and we measure the displacement of the sphere caused by the unfolding of the molecules in denaturing agents. In the case of bovine serum albumin, this "mechanical” size of the protein increases by 9 nm (a doubling of the folded dimensions) in strong denaturants. The present technique measures a size which is the maximum extent of the molecules, and is thus complementary to other existing methods which measure a radius of gyration. It gives access to the dynamics of conformational changes over time scales from milliseconds to minutes.
PACS: 87.15.He – Molecular dynamics and conformational changes / 07.07.Df – Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing / 36.20.Ey – Conformation (statistics and dynamics)
© EDP Sciences, 1996