Solvent caging of internal motions in myoglobin at low temperatures

Abstract

Experimental and simulation studies have reported the presence of a transition in the internal dynamics of proteins at 220 K. This transition has been correlated with the onset of activity in several proteins. The role of the solvent in the dynamical transition has been the subject of increased attention. Here simulation techniques are used to distinguish dynamical features inherent to the protein energy landscape from those induced by the surrounding solvent. The present results indicate that the protein dynamical transition primarily affects the side-chains on the outer layers of the protein. Moreover, the results indicate that the solvent restrains protein motions at low temperatures.