scholarly journals On the microscopic origin of the cryoprotective effect in lysine solutions

2020 ◽  
Vol 22 (13) ◽  
pp. 6919-6927 ◽  
Author(s):  
Andrés Henao ◽  
Guadalupe N. Ruiz ◽  
Nicola Steinke ◽  
Silvina Cerveny ◽  
Roberto Macovez ◽  
...  
Keyword(s):  
Amino Acid ◽  
Hydration Shell ◽  
Water Molecules ◽  
Microscopic Origin ◽  
First Hydration Shell

Lysine cryoprotective properties are due to the tight bonding of the first hydration Shell to the amino acid. However this effect is only possible for concentration up to 5.4 water molecules per lysine.

The Second Hydration Shell of Li+ in Aqueous LiI from X-Ray and MD Studies

1981 ◽  
Vol 36 (10) ◽  
pp. 1076-1082 ◽  
Author(s):  
T. Radnai ◽  
G. Pálinkás ◽  
Gy I. Szász ◽  
K. Heinzinger
Keyword(s):  
Hydration Shell ◽  
Distribution Functions ◽  
Dynamics Simulation ◽  
Scattering Data ◽  
Water Molecules ◽  
Radial Distribution Functions ◽  
Partial Structure ◽  
X Ray ◽  
Total Structure ◽  
First Hydration Shell

Indications from a molecular dynamics simulation of a 2.2 molal LiI solution of the existence of a second hydration shell of Li+ have been checked by an x-ray investigation of the same solution. The scattering data are analysed via partial structure functions and radial distribution functions which have been obtained from a model fitted to the total structure function. Experiment and simulation agree on first neighbor ion-water distances. An octahedral arrangement of six water molecules in the first hydration shell of Li+ and additional twelve water molecules in the second shell have been verified by the experiment.

A Molecular Dynamics Study of the Structure of an Aqueous CsF Solution

1983 ◽  
Vol 38 (2) ◽  
pp. 214-224 ◽  
Author(s):  
Gy. I. Szász ◽  
K. Heinzinger
Keyword(s):  
Molecular Dynamics ◽  
Hydration Shell ◽  
Distribution Functions ◽  
Dynamics Simulation ◽  
Water Model ◽  
Water Molecules ◽  
Heat Of Solution ◽  
Average Temperature ◽  
Experimental Density ◽  
First Hydration Shell

Abstract A molecular dynamics simulation of a 2.2 molal aqueous CsF solution has been performed employing the ST2 water model. The basic periodic cube with a sidelength of 18.50 Å contained 200 water molecules, and 8 ions of each kind, corresponding to an experimental density of 1.26 g/cm3. The simulation extended over 6.5 ps with an average temperature of 307 K. The structure of the solution is discussed by means of radial distribution functions and the orientation of the water molecules. The computed hydration numbers in the first shell of Cs+ and F- are 7.9 and 6.8, respectively; the corresponding first hydration shell radii are 3.22 A and 2.64 A, respectively. Values for the hydration shell energies and the heat of solution have been calculated.

scholarly journals Structure of the ordered hydration of amino acids in proteins: analysis of crystal structures

2015 ◽  
Vol 71 (11) ◽  
pp. 2192-2202 ◽  
Author(s):  
Lada Biedermannová ◽  
Bohdan Schneider
Keyword(s):  
Amino Acid ◽  
Crystal Structures ◽  
Structure Prediction ◽  
Solvent Accessibility ◽  
Hydration Shell ◽  
Protein Crystal ◽  
Water Molecules ◽  
Amino Acid Residues ◽  
Set Up ◽  
Dynamics Simulations

Crystallography provides unique information about the arrangement of water molecules near protein surfaces. Using a nonredundant set of 2818 protein crystal structures with a resolution of better than 1.8 Å, the extent and structure of the hydration shell of all 20 standard amino-acid residues were analyzed as function of the residue conformation, secondary structure and solvent accessibility. The results show how hydration depends on the amino-acid conformation and the environment in which it occurs. After conformational clustering of individual residues, the density distribution of water molecules was compiled and the preferred hydration sites were determined as maxima in the pseudo-electron-density representation of water distributions. Many hydration sites interact with both main-chain and side-chain amino-acid atoms, and several occurrences of hydration sites with less canonical contacts, such as carbon–donor hydrogen bonds, OH–π interactions and off-plane interactions with aromatic heteroatoms, are also reported. Information about the location and relative importance of the empirically determined preferred hydration sites in proteins has applications in improving the current methods of hydration-site prediction in molecular replacement, ab initio protein structure prediction and the set-up of molecular-dynamics simulations.

Spin-state dependence of the structural and vibrational properties of solvated iron(ii) polypyridyl complexes from AIMD simulations: II. aqueous [Fe(tpy)2]Cl2

2019 ◽  
Vol 21 (2) ◽  
pp. 650-661 ◽  
Author(s):  
Latévi M. Lawson Daku
Keyword(s):  
Hydration Shell ◽  
State Dependence ◽  
Distribution Functions ◽  
Water Molecules ◽  
Radial Distribution Functions ◽  
Spin States ◽  
Polypyridyl Complexes ◽  
Coordination Numbers ◽  
A Chain ◽  
First Hydration Shell

LS and HS Fe–O radial distribution functions and running coordination numbers for aqueous [Fe(tpy)2]Cl2: in both spin states, the first hydration shell of [Fe(tpy)2]2+ consists in a chain of ∼15 hydrogen-bonded water molecules wrapped around the ligands.

The dipole moment of water in the first hydration shell of a monovalent ion

1968 ◽  
Vol 46 (21) ◽  
pp. 2407-2411 ◽  
Author(s):  
Dieter K. Ross
Keyword(s):  
Dielectric Constant ◽  
Dipole Moment ◽  
Continuous Medium ◽  
Hydration Shell ◽  
Bulk Water ◽  
Water Molecules ◽  
The Mean ◽  
Monovalent Ion ◽  
Coordinated Water ◽  
First Hydration Shell

The mean dipole moment of the water molecules in contact with a monovalent ion is estimated. The first hydration shell of a spherical ion is assumed to contain either four or six coordinated water molecules, while the water molecules outside this shell are replaced by a continuous medium whose dielectric constant is that corresponding to bulk water at 25 °C. It is found that the dipole moment induced in the attached water molecules is comparable with its permanent dipole moment.

Origin of ion selectivity at the air/water interface

2015 ◽  
Vol 17 (6) ◽  
pp. 4311-4318 ◽  
Author(s):  
Lu Sun ◽  
Xin Li ◽  
Yaoquan Tu ◽  
Hans Ågren
Keyword(s):  
Hydrogen Bonds ◽  
Weak Interactions ◽  
Ion Selectivity ◽  
Hydration Shell ◽  
Water Molecules ◽  
Water Interface ◽  
Hydration Shells ◽  
Air Water Interface ◽  
Water Hydrogen ◽  
First Hydration Shell

A snapshot of a water droplet consisting of Cs+ and I− ions with their hydration structures displayed. I− is hydrated anisotropically and the water–water hydrogen bonds in the first hydration shell are hindered. The anions have quite weak interactions with non-hydrogen-bonded water molecules in the first hydration shell, making it easier for them to leave the site. In contrast, cations obtain more stable hydration shells with an increase in their size.

A Monte Carlo Study on a Magnesium Cyclen Complex

1988 ◽  
Vol 43 (8-9) ◽  
pp. 797-800
Author(s):  
Vithaya W. Ruangpornvisuti ◽  
Bernd M. Rode
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Potential Function ◽  
Hydration Shell ◽  
Monte Carlo Study ◽  
Intermolecular Potential ◽  
Water Molecules ◽  
First Hydration Shell

AbstractA Monte Carlo simulation has been performed to study the hydration of the magnesium complex of 1,4,7,10-tetraazacyclododecane (cyclen). An intermolecular potential function for magnesium cyclen complex and water, derived from ab initio calculations was used. The first hydration shell results to consist of 18 water molecules.

scholarly journals Hydration of the Ammonium Ion: Monte Carlo Simulation

1991 ◽  
Vol 46 (1-2) ◽  
pp. 107-110 ◽  
Author(s):  
R. Noto ◽  
V. Martorana ◽  
M. Migliore ◽  
S. L. Fornili
Keyword(s):  
Aqueous Solution ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Liquid Water ◽  
Infinite Dilution ◽  
Hydration Shell ◽  
Ammonium Ion ◽  
Water Molecules ◽  
Rotational Mobility ◽  
First Hydration Shell

AbstractA Monte Carlo simulation of ammonium aqueous solution at infinite dilution shows that this ion is on the average rather loosely bonded to three of the fourteen water molecules present in its first hydration shell. This result agrees with conclusions suggested by recent experiments on the rotational mobility of ammonium in liquid water.

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