We report zero-field NMR measurements of a viscous organic liquid, ethylene glycol. Zero-field spectra were taken showing resolved scalar spin-spin coupling (J-coupling) for ethylene glycol at different temperatures and water contents. Molecular dynamics strongly affects the resonance linewidth, which closely follows viscosity. Quantum chemical calculations have been used to obtain the relative...

When the first atomic structures of salt crystals were determined by the Braggs in 1912-1913, the analytical power of X-ray crystallography was immediately evident. Within a few decades the technique was being applied to the more complex molecules of chemistry and biology and is rightly regarded as the foundation stone of structural biology, a field that emerged in the 1950s when X-ray diffract...

A method to measure the polyol pathway metabolic flux in the intact rabbit lens by 13C nuclear magnetic resonance spectroscopy is described. In the lens exposed to 35.5 mM glucose, the polyol pathway accounts for 1/3 of the total glucose turnover. The high metabolic activity of the pathway suggests a significant alteration in the reduced to oxidized pyridine nucleotide ratio in the lens exposed...

An alkaloid from Maclurodendron porteri has been isolated and characterized. Extraction process was conducted by acid-base extraction method followed by column chromatography. The structure was established by nuclear magnetic resonance spectroscopy and mass spectrometry. The compound was identified as haplophytin B which occurs commonly in the Rutaceae family. However, this is the first time th...

Mutant human interleukin-la proteins were constructed by oligonucleotide directed mutagenesis. Six different mutants were tested for receptor binding activity and showed no alteration with respect to the wild-type protein. Analysis of these mutants by nuclear magnetic resonance spectroscopy confirmed the structural integrity of the mutant proteins and pcrmitted the sequence specific assignment ...

Interlock is a structural element in DNA G-quadruplexes that can be compared with the commonly used complementary binding of 'sticky ends' in DNA duplexes. G-quadruplex interlocking can be a basis for the assembly of higher-order structures. In this study, we formulated a rule to engineer (3 + 1) interlocked dimeric G-quadruplexes and established the folding topology of the designed DNA sequenc...

Native and recombined lipoproteins have been studied by (31)P nuclear magnetic resonance spectroscopy. Very low-, low-, and high-density lipoproteins exhibited characteristic spectra. The main resonances were assigned to phosphatidylcholine and sphingomyelin. Relaxation times for these phospholipids were separately measured in low-density lipoproteins and high-density lipoproteins. The effect o...

Alkaline phosphatase (EC 3.1.3.1) containing m-flurotyrosine has been prepared from E. coli grown in the presence of m-flurotyrosine. The kinetic properties of the m-fluorotyrosine enzyme measured with p-nitrophenylphosphate at pH 8.0 and dinitrophenylphosphate at pH 5.5 are essentially the same as those of normal alkaline phosphatase. However, the ability of the m-fluorotyrosine protein to ref...

Levan production by strains of Erwinia herbicola is common, and this property has some taxonomic significance for species differentiation within the "herbicola" group. The extracellular polysaccharide elaborated by strain 403 was characterized by nuclear magnetic resonance spectroscopy and methylation analysis. Results showed it to be a typical bacterial levan.

Galantamine hydrobromide was subjected to different stress conditions (acidic, alkaline, thermal, photolytic and oxidative). Degradation was found to occur under acidic, photolytic and oxidative conditions, while the drug was stable under alkaline and elevated temperature conditions. A stability-indicating reversed-phase liquid chromatographic method was developed for the determination of the d...