C-13 cross-polarization/magic angle spinning NMR studies of alpha-elastin preparations show retention of overall structure and reduction of mobility with a decreased number of cross-links

High-resolution solid-state C-13 NMR spectra are presented for samples of a -elastin prepared from the aorta of normal and copper-deficient pigs. Chemi cal shifts of the various peaks indicate that both the normal and undercros s-linked peptides have similar overall structures. However, C-13 T-1, C-13 T-1p, and H-1 T-1p measurements indicate that the alpha -elastin peptides o btained from the abnormal elastic fibers samples exhibit altered mobilities , particularly in their side chains. Results from spectra taken with a rang e of contact times and from dipolar dephasing experiments are consistent wi th conclusions reached with the relaxation measurements. Namely, the loss o f junction associated with the undercross-linked sample is correlated to a small but measurable difference in relative mobility. (C) 2001 John Wiley & Sons, Inc.