Effect of the Environment on the Protein Dynamical Transition: A Neutron Scattering Study

Paciaroni, Alessandro; Cinelli, Stefania; Onori, G.

doi:10.1016/s0006-3495(02)75239-9

Cited by 171 publications

(205 citation statements)

References 40 publications

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“…According to Roh et al [3], the values of T D at h = 0.30 and 0.45 are both around 200 K, which is substantially different from the results of T X shown in this study. Moreover, Paciaroni et al [2] report that T D even decreases as h increases. To account for these results, we conclude that the PDT is not directly or solely induced by the dynamic crossover in the protein hydration water.…”

Section: -3mentioning

confidence: 98%

“…Experimental studies show that the protein hydration water plays a key role in many aspects of protein behavior, which include the mean square displacement of the protein constituent atoms [2][3][4], the subpicosecond collective vibrations [5][6][7][8], the intraprotein α and β fluctuations [9,10], and the protein enzymatic activity [11]. Thus the study of the protein hydration water is crucial for the understanding of protein dynamics.…”

Section: Introductionmentioning

confidence: 99%

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Hydration-dependent dynamic crossover phenomenon in protein hydration water

Wang

Fratini

et al. 2014

Phys. Rev. E

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The characteristic relaxation time τ of protein hydration water exhibits a strong hydration level h dependence. The dynamic crossover is observed when h is higher than the monolayer hydration level h c = 0.2-0.25 and becomes more visible as h increases. When h is lower than h c , τ only exhibits Arrhenius behavior in the measured temperature range. The activation energy of the Arrhenius behavior is insensitive to h, indicating a local-like motion. Moreover, the h dependence of the crossover temperature shows that the protein dynamic transition is not directly or solely induced by the dynamic crossover in the hydration water.

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Section: -3mentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Hydration-dependent dynamic crossover phenomenon in protein hydration water

Wang

Fratini

et al. 2014

Phys. Rev. E

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“…We have not found such data. Some information comes from a neutron-scattering study on lysozyme embedded in pure glycerol (36) that showed that ͗x 2 (T) c ͘ for the glycerol and for the embedded lysozyme are identical. This result implies that the hydrogen atoms in the protein see the full motions of molecules in the shell and also suggests that glycerol can replace water.…”

Section: The ␤-Relaxation In Proteinsmentioning

confidence: 99%

Bulk-solvent and hydration-shell fluctuations, similar to α- and β-fluctuations in glasses, control protein motions and functions

Fenimore

Frauenfelder²,

McMahon³

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

504

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The concept that proteins exist in numerous different conformations or conformational substates, described by an energy landscape, is now accepted, but the dynamics is incompletely explored. We have previously shown that large-scale protein motions, such as the exit of a ligand from the protein interior, follow the dielectric fluctuations in the bulk solvent. Here, we demonstrate, by using mean-square displacements (msd) from Mö ssbauer and neutron P roteins are the molecules that perform most biological functions, from storage of dioxygen (O 2 ) to enzyme catalysis. A central goal of protein science is to relate structure, dynamics, and function. Although investigations of protein structures and functions are well organized industries, protein dynamics is still in its infancy. Dynamics studies are best performed on proteins whose structures and functions are well known, e.g., myoglobin (Mb), the protein that gives muscles their red color. A hybrid picture of Mb is shown in Fig. 1. The lower part displays a piece of the protein backbone, namely, three ␣-helices. The upper part presents a space-filling view of the protein atoms. The active center, a heme group with a central iron atom, is red. Two cavities are also shown, Xe1 and the heme cavity. The protein is surrounded by the hydration shell, one to two layers of water, and is embedded in the bulk solvent. In Mb's role as an oxygenstorage protein, O 2 enters the protein, stays some time in Xe1, then binds at the heme iron (1). CO follows a similar path through the protein. The structure of Mb shows no permanent channel that leads from the outside to either Xe1 or the heme pocket or from Xe1 to the heme pocket. Thus, structural fluctuations are necessary for function (2).Fluctuations imply that Mb possesses numerous different conformations, called conformational substates (CS) (3). The different CS can be described by an energy landscape (EL) (4), the central concept in the folding (5), dynamics, and function of proteins. The EL is a construct in Ϸ3N dimensions, where N is the number of atoms forming the protein and the hydration shell. A substate is a point in this hyperspace, and structural fluctuations are represented by jumps between points. Initially, we assumed that protein conformations could be organized into a simple, rough EL (1). Experiments showed, however, that there are wells within wells within wells, and an organization of the EL with several tiers of decreasing free-energy barriers ensued (6). The top tier, denoted by CS0, contains a small number of CS with different structures that can have different functions: in A 0 Mb is involved in NO enzymatics; in A 1 it acts as an oxygen-storage system (7). Each of the CS0 substates can assume a very large number of CS1, called statistical substates. They perform the same function but with different rates. Here, we will show that the statistical substates comprise two tiers, CS1␣ and CS1␤. Fluctuations between CS1␣ substates are slaved to the solvent motions and involve sizeable structural changes (8). ...

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“…The term 'slaving' has been used to express that water can impose its dynamical fingerprint on a protein 11,12 . Cryo-temperature dependent neutron scattering experiments revealed the solvent dependence of dynamical transitions in soluble proteins [13][14][15][16][17][18][19][20][21] and in RNA 22 and provided insights into the coupling between them. Molecular dynamics simulations suggested the onset of water translational diffusion to be at the origin of the dynamical transition 23,24 .…”

Section: Introductionmentioning

confidence: 99%

From shell to cell: neutron scattering studies of biological water dynamics and coupling to activity

et al. 2009

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An integrated picture of hydration shell dynamics and of its coupling to functional macromolecular motions is proposed from studies on a soluble protein, on a membrane protein in its natural lipid environment, and on the intracellular environment in bacteria and red blood cells. Water dynamics in multimolar salt solutions was also examined, in the context of the very slow water component previously discovered in the cytoplasm of extreme halophilic archaea. The data were obtained from neutron scattering by using deuterium labelling to focus on the dynamics of different parts of the complex systems examined.

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Effect of the Environment on the Protein Dynamical Transition: A Neutron Scattering Study

Cited by 171 publications

References 40 publications

Hydration-dependent dynamic crossover phenomenon in protein hydration water

Hydration-dependent dynamic crossover phenomenon in protein hydration water

Bulk-solvent and hydration-shell fluctuations, similar to α- and β-fluctuations in glasses, control protein motions and functions

From shell to cell: neutron scattering studies of biological water dynamics and coupling to activity

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