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Examination of a linear peptide with a type VI turn reveals the presence of sterical hindrance for the interactions of few of the proline ring protons with water solvent. NMR experiments suggest that close, specific packing between the proline and aromatic rings in the folded type VI turn conformation is responsible for the reduced accessibility of water to the proline ring protons. This differential hydration confirms that hydrophobic interactions between the aromatic and proline rings stabilize the turn structure.

The mechanism involved in the reaction CO2 + OH- -> HCO3(super 1-) is investigated. Geometries, electrostatic potential derived atomic point charges and thermodynamic corrections from normal mode analysis are determined at the RHF/6-31+G**//RHF/6-31+G** level for ab initio gas-phase calculations. Likewise, molecular dynamics free energy perturbation simulations are undertaken to develop a free energy of solvation curve. Results show that the reorganization of the water molecules proceeds with an energy cost of approximately 40 kcal/mol.

Research into the structure of the hydrated calcium(II) ion in aqueous solution is presented. It was found to be possible to calculate realistic theoretical extended X-ray absorption fine structure spectroscopy spectra for aqueous calcium chloride solutions.

It has been possible to make estimates of the solvent reorganization energy and entropy for methane in water on the basis of approximate calculations of the correlation functions involved. The main contribution to the entropy of hydrophobic hydration at room-temperature comes from solute-solvent correlations.

A study has been conducted to investigate the structural roles of hydration water molecules in stabilizing the higher-order structure of the Fe-type nitrile hydratase based on the crystal structure and results from light scattering measurements. Findings indicated that the hydration water molecules function as a glue for forming and stabilizing the alpha-beta heterodimer, the catalytic center and the (alpha-beta)2 heterotetramer.

The efficiency of lattice models in explaining the folding mechanism of proteins may be enhanced through a comprehensive description of solvation forces involved in the process. By introducing physically motivated solvation terms, researchers may be able to account for amino acid diversity, which leads to a more facilitated folding transition and unique ground states. These models are currently being studied to expand their applications to off-lattice simulations.

Research was conducted to examine the solution structure and dynamics of metal-bound water exchange in a series of lanthanide complexes of primary, secondary, and tertiary tetraamide derivatives of 1,4,7,10-tetraazacyclododecane. The relative proportions of the cationic gadolinium complexes of 12-N4-based tetraamide complexes that exist in solution as two isomers were governed by the nature of the amide substituents. Results indicate that new contrast agents may be developed by devising 'tetraazacyclododecane tetraacetate-like' complex structures wherein the proportion of the isomer in solution is maximized.

Research was conducted to determine the optimized potentials for liquid simulations-all atom (OPLS-AA) parameters for primary, secondary and tertiary amines and ammonia. The relative free energies of hydration, hydrogen bonding, molecular structures, pure liquid properties and conformational energetics were taken into account when developing the parameter set for methylamine, dimethylamine, trimethylamine and ammonia. Results suggest that the previous problems encountered with classical force fields for amines arose not from a critical omission but from nonoptimal parametrization.

The molecular structure, rotation and bonding of the S1

Widom particle insertion measurements combined with molecular dynamics simulation were used to study the effects of cosolvents on the solubility and hydration of small nonpolar solutes in solution. The solutes considered were helium, neon, argon and methane, while the solutions were sodium chloride, urea, ammonium sulfate, calcium chloride, ammonium acetate, guanidinium chloride, tetramethylammonium chloride and 2,2,2-trifluoroethanol. The degree of preferential cosolvent-solute binding for low cosolvent concentrations was found to be the key in determining the change in free energy of solvation.

Research was conducted to examine hydrophobic hydration and interactions on a molecular scale and the effects of pressure, temperature and salt concentration on them using a new theoretical approach. The objective is to improve the understanding of the molecular origins of hydrophobic effects. Results confirm that the basic information theory model provides a simple theoretical framework to study many hydrophobic phenomena on a molecular scale since it has already led to a new understanding of the temperature dependence of hydrophobic hydration.

A model solute imidazole, which was selected as a molecular solute to exemplify, combine and extend aspects of ionic and polar solutes studied previously, is presented. High accuracy results for molecular models permitted careful testing of simple theories of electrostatic hydration free energies. The simplest theories, dielectric continuum models, have been found to be rough despite the fact that they can always be adjusted to reproduce an empirical answer given a priori.

An investigation on the reverse micelles of triblock copolymers poly(ethylene oxide)-block-poly(propylene oxide)-block-poly-(ethylene oxide) EO6PO36EO6 (Pluronic L62) and EO13PO30EO13 (Pluronic L64) in ternary and binary systems with different water contents was conducted using fluorescence, absorption and spin probe techniques. The results gave complementary and concordant conclusions regarding micellization, hydration and microviscosity in various micellar zones.

A study was conducted to analyze the hydration of MgAl layered double hydroxides supporting an interlayer terephthalate anions and controlled layer charge. Powder x-ry diffraction, thermal gravimmetry and computer simulation were carried out to examine the influence of layer charge density and interlayer water content on the interlayer arrangement. Results indicated that the orientation of the terepthalate anion correlated with the hydroxide layer charge and the interlayer water content of the layered double hydroxides.

A study was conducted to analyze the weak, polarized Raman band assigned to the v1 CdO6 mode of the hexaquo Cd(II) ion over the temperature range 25-152 degrees C. The true vibrational contribution of the band was determined using the isotropic scattering geometry. The Raman spectra of the Cd(ClO4)2 solution was then obtained at three different temperatures. In addition, ab initio geometry optimizations were performed at the Hartree-Fock and second-order Moller-Plesset levels of theory.

Research was conducted to examine the hydration of beryllium, magnesium, calcium and zinc ions using density functional theory. The representative metals were chosen to investigate the coordinative behavior of doubly charged metal ions in water. Results indicate that the water dipole moments and polarizabilities, which are critical for the accuracy of the binding energies, are well reproduced when the basis set on the metal is included in the calculations.

Several of the data presented in Table 1 on page 10161 are wrong. A corrected table of the values for A, C, G and T is presented.