Infrared and Fourier transform Raman spectra are reported for dried mixtures of trehalose and lysozyme. The Raman spectra show effects on the protein amide I band and some sugar bands that are not present when the components are dried separately. Comparison of ir spectra with those published previously show significant differences. It is concluded that these arise because of differences in the extent of drying of the moisture, and that, contrary to some claims, vibrational spectroscopy does not so far show any clear evidence of specific trehalose/protein interactions and that results may be interpreted in terms of entrapment of water within the mixture.

Two-dimensional (1)H-(13)C MAS-J-HMQC solid-state NMR spectra of the two anomeric forms of maltose at natural abundance are presented. The experimental (1)H chemical shifts of the CH and CH(2) protons are assigned using first-principles chemical shift calculations that employ a plane-wave pseudopotential approach. Further calculations show that the calculated change in the (1)H chemical shift when comparing the full crystal and an isolated molecule is a quantitative measure of intermolecular C-H...O weak hydrogen bonding. Notably, a clear correlation between a large chemical shift change (up to 2 ppm) and both a short H...O distance (<2.7 A) and a CHO bond angle greater than 130 degrees is observed, thus showing that directionality is important in C-H...O hydrogen bonding.