Biological water: A critique

Zhong, Dongping; Pal, Samir Kumar; Zewail, Ahmed H.

doi:10.1016/j.cplett.2010.12.077

Cited by 261 publications

(311 citation statements)

References 75 publications

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“…12 and MM are the total dipole moment of first and second layers respectively. The protein surface is generally rugged even for a globular protein.…”

Section: B Ktmentioning

confidence: 99%

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Distinguishing dynamical features of water inside protein hydration layer: Distribution reveals what is hidden behind the average

Mukherjee

Mondal

Bagchi

2017

The Journal of Chemical Physics

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Since the pioneering works of Pethig, Grant and Wüthrich on protein hydration layer, many studies have been devoted to find out if there are any "general and universal" characteristic features that can distinguish water molecules inside the protein hydration layer from bulk. Given that the surface itself varies from protein to protein, and that each surface facing the water is heterogeneous, search for universal features has been elusive.Here, we perform atomistic molecular dynamics simulation in order to propose and demonstrate that such defining characteristics can emerge if we look not at average properties but the distribution of relaxation times. We present results of calculations of distributions of residence times and rotational relaxation times for four different proteinwater systems, and compare them with the same quantities in the bulk. The distributions in the hydration layer is unusually broad and log-normal in nature, due to the simultaneous presence of peptide backbones that form weak hydrogen bonds, hydrophobic amino acid side chains that form no hydrogen bond and charged polar groups that form strong hydrogen bond with the surrounding water molecules. The broad distribution is responsible for the non-exponential dielectric response and also agrees with large specific heat of the hydration water. Our calculations reveal that while the average time constant is just about 2-3 times larger than that of bulk water, it provides a poor representation of the real behaviour. In particular, the average leads to the erroneous conclusion that water in the hydration layer is bulk-like. However, the observed and calculated lower value of static dielectric constant of hydration layer remained difficult to reconcile with the broad distribution observed in dynamical properties. We offer a plausible explanation of these unique properties.

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“…12 and MM are the total dipole moment of first and second layers respectively. The protein surface is generally rugged even for a globular protein.…”

Section: B Ktmentioning

confidence: 99%

“…Much later, the problem was re-visited by employing improved NMR techniques [27][28][29] , time dependent fluorescence Stokes shift (TDFSS) studies 12,30,31 and also computer simulation studies 2,[32][33][34] . New NMR experiments all but rule out existence of any slow component 28,35 .…”

Section: Introductionmentioning

confidence: 99%

Distinguishing dynamical features of water inside protein hydration layer: Distribution reveals what is hidden behind the average

Mukherjee

Mondal

Bagchi

2017

The Journal of Chemical Physics

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“…Strongly altered hydrogen-bond dynamics in the lipid hydration shells have been observed in the experiments addressing water translational mobility, reorientation, and hydrogen-bond strength. [10][11][12][13][14][15] Interestingly, such studies indicate coupling between the dynamics of water and biological objects which may imply a strong interaction between the solute and the hydration shell. 16,17 It is well known that structure, dynamics and even macroscopic properties of water are determined by the strong intermolecular interactions between the hydrogen-bonded water molecules.…”

Section: Introductionmentioning

confidence: 99%

Reduced coupling of water molecules near the surface of reverse micelles

Bakulin

Pshenichnikov

2011

Phys. Chem. Chem. Phys.

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“…27 mol H 2 O/mol CA(1-7)M(2-9)), it follows that the glass transition temperature increases as the amount of the bound water decreases and does not seem to depend on the free water content. The recent work of Zhong et al 15 also shows that there are two types of hydration water, those that reorient in the vicinity of a surface and those which are ordered, yet in dynamic interaction with the protein. Our results point in the same direction, as two types of water could be derived from the adiabatic calorimetry results and by neutron scattering we could see a strong correlation between water dynamics and protein's slow, long range motion at temperatures above 220 K, as discussed above.…”

Section: Discussionmentioning

confidence: 99%

“…Nevertheless, many aspects regarding its particular structure near the surface and inside biological macromolecules as well as its link to biological function are still under discussion. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Proteins are known to have a ''limiting hydration'' necessary for function, and thus there must exist a link between hydration and protein functional properties.…”

Section: Introductionmentioning

confidence: 99%

Hydration water and peptide dynamics – two sides of a coin. A neutron scattering and adiabatic calorimetry study at low hydration and cryogenic temperatures

Bastos

Alves

Maia

et al. 2013

Phys. Chem. Chem. Phys.

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In the present work we bridge neutron scattering and calorimetry in the study of a low-hydration sample of a 15-residue hybrid peptide from cecropin and mellitin CA(1-7)M(2-9) of proven antimicrobial activity.Quasielastic and low-frequency inelastic neutron spectra were measured at defined hydration levelsa nominally 'dry' sample (specific residual hydration h = 0.060 g/g), a H 2 O-hydrated (h = 0.49) and a D 2 Ohydrated one (h = 0.51). Averaged mean square proton mobilities were derived over a large temperature range (50-300 K) and the vibrational density of states (VDOS) were evaluated for the hydrated samples. The heat capacity of the H 2 O-hydrated CA(1-7)M(2-9) peptide was measured by adiabatic calorimetry in the temperature range 5-300 K, for different hydration levels. The glass transition and water crystallization temperatures were derived in each case. The existence of different types of water was inferred and their amounts calculated. The heat capacities as obtained from direct calorimetric measurements were compared to the values derived from the neutron spectroscopy by way of integrating appropriately normalized VDOS functions. While there is remarkable agreement with respect to both temperature dependence and glass transition temperatures, the results also show that the VDOS derived part represents only a fraction of the total heat capacity obtained from calorimetry. Finally our results indicate that both hydration water and the peptide are involved in the experimentally observed transitions.

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Biological water: A critique

Cited by 261 publications

References 75 publications

Distinguishing dynamical features of water inside protein hydration layer: Distribution reveals what is hidden behind the average

Distinguishing dynamical features of water inside protein hydration layer: Distribution reveals what is hidden behind the average

Reduced coupling of water molecules near the surface of reverse micelles

Hydration water and peptide dynamics – two sides of a coin. A neutron scattering and adiabatic calorimetry study at low hydration and cryogenic temperatures

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