A model protein and surrounding water have been investigated at different temperatures. We have detected an anomalous compression of the protein near the freezing point of water—a compression not obviously related to the negative thermal expansion of the solvent. Moreover, the physiological protein working temperature (T=300??K) appears to be related to the activation of exchange of vicinal water with the bulk and the concomitant absorption of heat by hydrophilic amino acids. The inferred activation was interpreted on the basis of degenerate tetrahedral order between the hydration shell and the bulk. The results support the notion that the dynamics of vicinal water makes a substantial contribution to the activity optimum of proteins.
Water induced effects on the thermal response of a protein / Melchionna, S; Briganti, Giuseppe; Londei, Paola; Cammarano, Piero. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - STAMPA. - 92:(2004), pp. 158101-158105. [10.1103/PhysRevLett.92.158101]
Water induced effects on the thermal response of a protein
BRIGANTI, Giuseppe;LONDEI, Paola;CAMMARANO, Piero
2004
Abstract
A model protein and surrounding water have been investigated at different temperatures. We have detected an anomalous compression of the protein near the freezing point of water—a compression not obviously related to the negative thermal expansion of the solvent. Moreover, the physiological protein working temperature (T=300??K) appears to be related to the activation of exchange of vicinal water with the bulk and the concomitant absorption of heat by hydrophilic amino acids. The inferred activation was interpreted on the basis of degenerate tetrahedral order between the hydration shell and the bulk. The results support the notion that the dynamics of vicinal water makes a substantial contribution to the activity optimum of proteins.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
