Characterization of leucine side-chain reorientation in collagen-fibrils by solid-state 2H NMR (original) (raw)

1982, Proceedings of the National Academy of Sciences

We have used 2H quadrupole-echo NMR spectroscopy to study the molecular dynamics of the leucine side chain in collagen fibrils labeled with [2H10]leucine. X-ray crystallographic studies of leucine and small leucyl-containing peptides and proteins [Benedetti, C. (1977) in Proceedings of the Fifth American Peptides Symposium, eds, Goodman, M. & Meienhofer, J. (Wiley, New York), pp. 257--274; Janin, J., Wodak, S., Levitt, M. & Maigret, B. (1978) J. Mol. Biol. 125, 357--386] show that the amino acid side chain exists predominantly in only two of the nine possible conformations. 2H NMR spectra of polycrystalline D,L [2H10]leucine obtained from -45 degrees C to +100 degrees C showed that interconversion of the two conformations did not take place on the 2H NMR timescale in this temperature range. In contrast, experimental lineshapes observed for [2H10]leucine-labeled collagen fibrils from -85 degrees C to +30 degrees C were simulated by using a model in which the side chain hops at variou...