The molecular structure and physical properties of elastin fibers as revealed by Raman microspectroscopy

Abstract Raman microspectroscopy has been used to investigate the structure of α‐elastin and fibrous elastin from ligament and aorta, and to explore changes associated with mechanical strain and temperature. Although no vibrational modes associated with cross‐linking of the fibers could be identified, the secondary structure of dehydrated fibrous elastin was significantly different from α‐elastin. The former differed from previous experimental measurements, but was close to the theoretical predictions with 36% β‐structures, 46% unordered, and 18% α‐helix. α‐Elastin contained 29% β‐structures, 53% unordered, and 18% α‐helix. In nuchal fibers the amide I mode was polarized, consistent with the peptide bond. Strains of up to 60% in ligament fiber bundles resulted in no significant shifts in peak position or in secondary structure. Polarization measurements revealed that the peptide bonds and several side chains re‐orientated closer to the fiber axis. Heating nuchal fibers to 60°C to increase the energetic component of the elasticity was associated with a 30% increase in the proportion of β‐structures in the amide I band, a 50% increase in the amide III band, and a 50% reduction in the signal from bound water. © 2008 Wiley Periodicals, Inc. Biopolymers 89: 931–940, 2008. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com