Low energy dynamics of globular proteins studied by inelastic neutron scattering

In order to reveal the dynamical properties specific to the folded protein, inelastic neutron scattering measurements were performed for the folded an d the unfolded Staphylococcal nuclease, and myoglobin at 100 K and 300 K. T he observed S(Q, omega) at 100 K for these three were essentially identical . Protein individuality was not expressed in the low energy dynamics at low temperature. The peak position of low energy excitation showed molecular w eight dependence, suggesting that the excitation is originated from modes e xtended over a whole molecule. The changes in dynamical properties upon fol ding were observed at 300 K, suggesting that anharmonic motion is essential for function. (C) 1999 Published by Elsevier Science Ltd. All rights reser ved.