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Titolo:
Low frequency anomaly in the hydration water of Copper Azurin
Autore:
Paciaroni, A; Bizzarri, AR; Cannistraro, S;
Indirizzi:
Univ Perugia, Dipartimento Fis, Unita INFM, I-06100 Perugia, Italy Univ Perugia Perugia Italy I-06100 s, Unita INFM, I-06100 Perugia, Italy Univ Tuscia, Dipartimento Sci Ambientali, I-01100 Viterbo, Italy Univ Tuscia Viterbo Italy I-01100 Sci Ambientali, I-01100 Viterbo, Italy
Titolo Testata:
PHYSICA B
fascicolo: 3-4, volume: 269, anno: 1999,
pagine: 409 - 415
SICI:
0921-4526(199909)269:3-4<409:LFAITH>2.0.ZU;2-W
Fonte:
ISI
Lingua:
ENG
Soggetto:
MOLECULAR-DYNAMICS SIMULATION; INELASTIC NEUTRON-SCATTERING; GLASS-TRANSITION; BOSON PEAK; PROTEIN; MYOGLOBIN; PLASTOCYANIN; LIQUIDS; DIFFUSION; BEHAVIOR;
Keywords:
Copper Azurin; molecular-dynamics simulation;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
41
Recensione:
Indirizzi per estratti:
Indirizzo: Cannistraro, S Univ Perugia, Dipartimento Fis, Unita INFM, I-06100 Perugia, Italy Univ Perugia Perugia Italy I-06100 I-06100 Perugia, Italy
Citazione:
A. Paciaroni et al., "Low frequency anomaly in the hydration water of Copper Azurin", PHYSICA B, 269(3-4), 1999, pp. 409-415

Abstract

A molecular-dynamics (MD) simulation of hydrated Copper Azurin has been performed at different temperatures to study the single-particle dynamics of water surrounding the protein. The self-intermediate scattering function I(ri, t) of the water hydrogen atoms, is characterized by a two step relaxation behaviour at low temperature, where the fast relaxation is distinctly separated from the slower one by a plateau. Such a feature is in qualitative agreement with that recently obtained by MD studies on supercooled bulk water. The dynamical structure factor of hydration water, derived by a time Fourier transform of I(q, t), shows a broad peak in the inelastic low-frequency region (similar to 1.3 meV); such a peak being particularly evident at low temperatures. This inelastic peak, whose intensity shows a q(2) dependence, is reminiscent of the so-called boson peak, experimentally observed in several amorphous disordered materials. An additional evidence of this boson peak is provided by the presence of an excess of modes, with respect to the Debye model, in the hydration water vibrational density of states g(upsilon), which has been calculated from the spectral density of the hydrogen velocity autocorrelation function. The reliability of the present MD simulations is further emphasized by the good agreement of the calculated dynamical susceptibility with that recently obtained by scattering experiments in similar systems. Possible implications of the hydration water low-frequency inelastic anomalies in the protein-solvent dynamical coupling mechanism arebriefly discussed. (C) 1999 Elsevier Science B.V. All rights reserved.

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Documento generato il 28/11/20 alle ore 00:22:24