The empirical rules for estimating molar rotations of carbohydrate structures proposed by Whiffen and elaborated by Brewster provided interpretations of solvent effects on optical rotation with changes in conformational equilibria which in certain cases were confirmed by n.m.r. Conversely, it was found that only slight changes in rotation occur on changing the solvent for conformationally rigid...

The crystal structure of the oxidized form of flavodoxin from Desulfovibrio vulgaris has been studied at 2.0-A resolution, and a detailed description of the region around the flavin mononucleotide binding site is now available. The flavin is between a tyrosine group, roughly parallel to it on one side, and a tryptophan, about 45 degrees from being parallel, on the other side. The two carbonyl g...

The ESR parameters of PC spin labels in frozen membranes do not simply represent the membrane polarity or water penetration profile. Instead, they show a distribution between hydrogen-bonded (HB) and non-hydrogen-bonded (non-HB) states, which is affected by a number of factors in the membrane composition. Similar to the exclusion of solutes from crystallizing solvents, the pure bulk gel phase e...

Protein$\alpha$-helices provide an ordered biological environment that is conducive to soliton-assisted energy transport. The nonlinear interaction between amide I excitons and phonon deformations induced in the hydrogen-bonded lattice of peptide groups leads self-trapping energy, thereby creating a localized quasiparticle (soliton) persists at zero temperature. presence thermal noise, however,...

Hydrogen-bonding and intra/intermolecular vibrational coupling of water next to a hydrophobic molecule (tert-butyl alcohol, TBA) have been studied by Raman multivariate curve resolution (Raman-MCR) and isotopic dilution spectroscopy. Raman-MCR provides the vibrational spectrum of water pertinent to the hydration shell of TBA, which shows a distinct Raman band at around 3660 cm(-1) corresponding...

Sputtering of condensed-phase ammoniumnitrate yields an extensivedistribution of negative cluster ions of the form [(NH4N03),N03]-, n 2 3. Collision-induced dissociation of mass-selected cluster ions suggests that the first two members of the series, n = 1 and n = 2, are missing because the ions rearrange to lose one or more ammonia molecules. Gradient-corrected density-functional calculations ...