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Infrared, Raman and INS spectra of picolinic acid N-oxide (PANO) are examined for the location of the hydronic modes such as hydrogen bonds. The hydrogen bonding in PANO is investigated by hydronium potential fluctuation.

The proton dynamics in the medium-strong intramolecular hydrogen bond of acetylacetone (Pentane-2,4-dione) was studied using the mixed quantum-classical method density matrix evolution (DME). It was possible to stimulate the vibrational spectrum of strong hydrogen-bonded systems in polar solutions.

The proton potential in the medium-strong intramolecular hydrogen bond of acetylacetone was examined on various ab initio and density functional theory levels. It was shown that the proton donor-proton acceptor influences the barrier heights while both CO distances introduce the asymmetry.

Abstract Background For a long time IBs were considered to be inactive deposits of accumulated target proteins. In our previous studies, we discovered IBs containing a high percentage of correctly folded protein that can be extracted under non-denaturing conditions in biologically active form without applying any renaturation steps. In order to widen the concept of correctly folded protein inside IBs, G-CSF (granulocyte colony stimulating factor) and three additional proteins were chosen for this study: GFP (Green fluorescent protein), His7dN6TNF-α (Truncated form of Tumor necrosis factor α with an N-terminal histidine tag) and dN19 LT-α (Truncated form of Lymphotoxin α). Results Four structurally different proteins that accumulate in the bacterial cell in the form of IBs were studied, revealing that distribution of each target protein between the soluble fraction (cytoplasm) and insoluble fraction (IBs) depends on the nature of the target protein. Irrespective of the folding pattern of each protein, spectroscopy studies have shown that proteins in IBs exhibit similar structural characteristics to the biologically active pure protein when produced at low temperature. In the case of the three studied proteins, G-CSF, His7ΔN6TNF-α, and GFP, a significant amount of protein could be extracted from IBs with 0.2% N-lauroyl sarcosine (NLS) and the proteins retained biological activity although no renaturation procedure was applied. Conclusion This study shows that the presence of biologically active proteins inside IBs is more general than usually believed. A large amount of properly folded protein is trapped inside IBs prepared at lower temperatures. This protein can be released from IBs with mild detergents under non-denaturing conditions. Therefore, the active protein can be obtained from such IBs without any renaturation procedure. This is of great importance for the biopharmaceutical industry. Furthermore, such IBs composed of active proteins could also be used as pure nanoparticles in diagnostics, as biocatalysts in enzymatic processes, or even as biopharmaceuticals.

The conformational preferences of 13 dipeptides are studied by using infrared and Raman spectroscopy. The results have shown that alanine dipeptide has adopted a [P.sub.II] conformation and the population of the [beta] conformation has increased in valine dipeptides.

A novel synthetic method is developed for a salt of 2-{[2-(3,4-dichlorophenyl)-ethyl]propylamino}-1-pyridin-3-ylethanol and the dynamic and conformational properties of its salt form are characterized. The results have shown a diastereomeric effect in the salt form of a racemic tertiary arylalkylamine and some NMR spectroscopic evidence are provided to demonstrate the mechanisms underlying this effect.

A study is conducted to show that a new sol-gel precursor consists of positively charged polyhedral cubelike silsesquioxanes. The result reveals that over the course of condensation of sols, the refractive index of the modes attributed to the polysilsesquioxanes species exhibited strong dispersion, which led to a shift of the vibrational band position in the experimental ATR spectra.

The structure and the gasochromic properties of sol-gel-derived WO3 films with a monoclinic structure ( m-WO3) were studied by focusing attention on the size of the monoclinic grains. The size of the m-WO3 grains is modified by the addition of an organic–inorganic hybrid to the initial peroxopolytungstic acid (W- PTA) sols which are based on chemically bonded poly-(propylene glycol) to triethoxysilane end-capping groups ( ICS- PPG). The results obtained with scanning electron microscopy (SEM) and transmission electron microscopy (TEM) show that the heat treatment (500°C) of WO3/ ICS- PPG (0.5, 1, 2, 5, and 10 mol%) composite films results in a change of their morphology, and nanodimensional pores are formed between the grains. High-resolution TEM (HRTEM) analysis revealed the presence of an amorphous phase on the outside of the m-WO3 grains, whereas energy-dispersive X-ray spectra (EDXS) showed that this amorphous phase contained W and Si. Impregnation of the WO3/ ICS- PPG film with H2PtCl6/ i-propanol solution followed by heat treatment at 380°C gave the films their gasochromic properties. Infrared and Raman spectroscopic studies of the WO3/ ICS- PPG film confirmed the results of the corresponding HRTEM and EDXS analysis. In situ UV/Vis and in situ IR spectra of the films were measured in hydrogen and in air, and colouring/bleaching changes and the corresponding kinetics were assessed. The IR spectra of gasochromically coloured films showed that the mesoporous WO3/ ICS- PPG (1 mol%) film transforms to tetragonal H xWO3 bronze. The IR spectra of the H xWO3 bronze are discussed with the aim to establish the existence of the metal-OH vibrations of gasochromically formed oxyhydroxide tungsten bronze. [ABSTRACT FROM AUTHOR]

Glutathione is the most abundant low molecular weight thiol-containing molecule in biological cells with a strong tendency to interact with metal ions. Among the eight possible glutathione binding sites, only two are determined as groups that interact with the Cd2+ ion. Analysis of vibrational spectra and 13C and 1H NMR spectra revealed that thiol and glutamyl's carboxylic groups are groups that cooperate in interaction with Cd2+ ions. The coordination of Cd2+ with those groups was supported by the application of auxiliary molecules (D-penicillamine, glycine, cysteine and glutamic acid dipeptides, mercaptosuccinic acid and N-acetyl-L-cysteine). These molecules provide a reliable assignment of the fundamental vibrations in the glutathione vibrational spectra. Concentration-dependent measurements of Cd2+ ions showed that the optimal stoichiometry of coordination with the glutathione molecule is 1:1. The analysis of 3J (Halpha, H(N)) coupling constants and conformational sensitive bands in the glutathione vibrational spectra suggest that interaction with Cd2+ ions significantly alters glutathione backbone conformation. The binding of ions induced the conformational change of the cysteine backbone from a predominantly beta structure to P(II).