Biophysical study of thermal denaturation of apo-calmodulin: II- Dynamics of native and unfolded states

¹ Laboratoire Léon Brillouin (CEA/CNRS)
² Inserm U759 / Institut Curie-Recherche

^* To whom correspondence should be addressed. E-mail: gabriel.gibrat{at}cea.fr.

Submitted on August 18, 2007
Revised on September 10, 2007
Accepted on 10 October 2007

	Abstract

Apo-calmodulin, a small, mainly , soluble protein is a calcium-dependent protein activator. This paper presents a study of internal dynamics of native and thermal unfolded apo-calmodulin, using quasi-elastic neutron scattering. This technique can probe protein internal dynamics in the picosecond time-scale and in the nm length-scale. It appears that a dynamical transition is associated with thermal denaturation of apo-calmodulin. This dynamical transition goes together with a decrease of the confinement of hydrogen atoms, a decrease of immobile protons proportion and an increase of dynamical heterogeneity. The comparison of native and unfolded states dynamics suggests that the dynamics of protein atoms is more influenced by their distance to the backbone than by their solvent exposure.

Key Words: Calmodulin, Denatured states, Dynamics, Protein, Quasi-elastic neutron scattering, Time of flight