Intrinsic motional displacements and function in proteins

Scientific Achievement

A method for determining the intrinsic mean square displacement (MSD) of hydrogen (H) in proteins from resolution dependent neutron scattering data has been developed.

Significance and Impact

The MSD of H in proteins is used as an indicator of whether proteins will function. A large MSD is associated with function. Obtaining the intrinsic, instrument independent values of the MSD in proteins is critical to accurate use of this function indicator. Research Details

– A simple model is fitted to instrument dependent data, either new or already in the literature, to obtain the intrinsic MSD in biological molecules. The Intrinsic MSD is always larger than instrument broaded, observed MSD. The intrinsic dynamical transition (DT) temperature is always lower than the observed DT temperature.

The mean square displacement (MSD) in Angstroms of hydrogen in the protein HS-0.4 vs temperature. The squares are the MSD observed on instruments IN16, IN13 and IN6 which depend on the instrument resolution W. The red dots are the intrinsic MSD obtained from a fit to the same data. The red solid line, the intrinsic MSD drawn through the red dots, is independent of the instrument resolution width W.

D Vural, HR Glyde, Physical Review B 86, 011926 (2012). Research conducted at the University of Delaware