nowadays nmr spectroscopy becomes a powerful tool in chemistry because of the nmr chemical shifts. hartree–fock theory and the gauge-including atomic orbital (giao) methods are used in the calculation of 29si nmr chemical shifts of various silicate species in the silicate solution as initial components for zeolite synthesis both in gas and solution phase. calculations have been performed at geo...

The interactions of the carboxyl group of oleic acid with bovine serum albumin (BSA) were studied by 13C NMR spectroscopy at 50.3 MHz using 90% isotopically substituted [1-13C]oleic acid. 13C NMR spectra were obtained as a function of the mole ratio of oleic acid to BSA (from 0.5-10.0) and, for selected mole ratios, as a function of pH (between pH 3.0 and 10.6) and temperature (between 15 and 5...

Zinc is the second most abundant metal ion incorporated in proteins, and is in many cases a crucial component of protein three-dimensional structures. Zinc ions are frequently coordinated by cysteine and histidine residues. Whereas cysteines bind to zinc via their unique S(γ) atom, histidines can coordinate zinc with two different coordination modes, either N(δ1) or N(ε2) is coordinating the zi...

Chemical shifts reflect the structural environment of a certain nucleus and can be used to extract structural and dynamic information. Proper calibration is indispensable to extract such information from chemical shifts. Whereas a variety of procedures exist to verify the chemical shift calibration for proteins, no such procedure is available for RNAs to date. We present here a procedure to ana...

Nuclear magnetic resonance (NMR) spectroscopy uses the magnetic spin properties of atomic nuclei within a molecule to identify atoms that are close together in space (either because they are bonded together or because folds of a protein chain bring them together). This information is used to derive a three-dimensional model of a protein in solution (a ‘solution structure’). Only certain isotope...

Even as available magnetic fields for NMR continue to increase, resolution remains one of the most critical limitations in assigning and solving structures of larger biomolecules. Here we present a novel constant-time through-bond correlation spectroscopy for solids that offers superior resolution for 13C chemical shift assignments in proteins. In this experiment, the indirect evolution and tra...

Post-translational modifications of proteins expand the diversity of the proteome by several orders of magnitude and have a profound effect on several biological processes. Their detection by experimental methods is not free of limitations such as the amount of sample needed or the use of destructive procedures to obtain the sample. Certainly, new approaches are needed and, therefore, we explor...

The 13C NMR chemical shift of sp2 carbon atoms in acyclic alkenes was estimated with multilayer feedforward artificial neural networks (ANNs) and multilinear regression (MLR), using as structural descriptors a vector made of 12 components encoding the environment of the resonating carbon atom. The neural network quantitative model provides better results than the MLR model calibrated with the s...

Paramagnetic metal ions can induce molecular alignment with respect to the magnetic field. This alignment generates residual anisotropic chemical shifts (RACS) due to nonisotropic averaging over the molecular orientations. Using a 30 kDa protein-protein complex, the RACS effects are shown to be significant for heteronuclear spins with large chemical shift anisotropies, lanthanide ions with larg...