Chen, Sow-Hsin Lagi, Marco Chu, Xiang-qiang Zhang, Yang Kim, Chansoo Faraone, Antonio Fratini, Emiliano Baglioni, Piero 2024-01-20T19:34:46Z 2024-01-20T19:34:46Z 2021-09-04 2010-03 0712-4813 https://pubs.kist.re.kr/handle/201004/131670 This review article describes our neutron scattering experiments made in the past four years for the understanding of the single-particle (hydrogen atom) dynamics of a protein and its hydration water and the strong coupling between them. We found that the key to this strong coupling is the existence of a fragile-to-strong dynamic crossover (FSC) phenomenon occurring at around T-L = 225 +/- 5 K in the hydration water. On lowering of the temperature toward FSC, the structure of hydration water makes a transition from predominantly the high density form (HDL), a more fluid state, to predominantly the low density form (LDL), a less fluid state, derived from the existence of a liquid liquid critical point at an elevated pressure. We show experimentally that this sudden switch in the mobility of hydration water on Lysozyme. B-DNA and RNA triggers the dynamic transition, at a temperature T-D = 220 K. for these biopolymers. In the glassy state, below T-D. the biopolymers lose their vital conformational flexibility resulting in a substantial diminishing of their biological functions. We also performed molecular dynamics (MD) simulations on a realistic model of hydrated lysozyme powder, which confirms the existence of the FSC and the hydration level dependence of the FSC temperature. Furthermore, we show a striking feature in the short time relaxation (beta-relaxation) of protein dynamics. which is the logarithmic decay spanning 3 decades (from ps to ns). The long time alpha-relaxation shows instead a diffusive behavior, which supports the liquid-like motions of protein constituents. We then discuss our recent high-resolution X-ray inelastic scattering studies of globular proteins. Lysozyme and Bovine Serum Albumin. We were able to measure the dispersion relations of collective, intra-protein phonon-like excitations in these proteins for the first time. We found that the phonon energies show a marked softening and at the same time their population increases substantially in a certain wave vector range when temperature crosses over the T-D. Thus the increase of biological activities above T-D has positive correlation with activation of slower and large amplitude collective motions of a protein. English HINDAWI PUBLISHING CORP Dynamics of a globular protein and its hydration water studied by neutron scattering and MD simulations Article 10.3233/SPE-2010-0409 1 SPECTROSCOPY-AN INTERNATIONAL JOURNAL, v.24, no.1-2, pp.1 - 24 SPECTROSCOPY-AN INTERNATIONAL JOURNAL 24 1-2 1 24 N scie scopus 000278029800001 2-s2.0-77953732984 Biochemical Research Methods Spectroscopy Biochemistry & Molecular Biology Spectroscopy Article; Proceedings Paper HIGH-PRESSURE GLASS-TRANSITION SILICA MATERIALS CONFINED WATER SLOW DYNAMICS LIQUID-PHASE TEMPERATURE MYOGLOBIN CROSSOVER SOLVENT