CONFORMATIONAL CHARACTERIZATION OF WOOL KERATIN AND S-(CARBOXYMETHYL)KERATEINE IN THE SOLID-STATE BY C-13 CP/MAS NMR-SPECTROSCOPY

13C CP/MAS NMR spectra of native wool fiber and four kinds of S-(carboxymethyl)kerateines extracted from wool (low-sulfur fractions (SCMKA), helix-rich fragments (SCMKA-hf), high-sulfur fractions (SCMKB), and high-glycine–tyrosine fractions (HGT)) were measured in the solid state. By use of the observed13C chemical shift values of the main-chain carbonyl carbons, the major conformations of SCMKA and SCMKA-hf were determined to be the right-handed α-helix form and those of SCMKB and HGT to be the β-sheet form. It was also confirmed that both the right-handed α-helix and β-sheet forms exist in native wool fiber. Further, it was suggested that the coiled-coil structure exists in wool, SCMKA, and SCMKA-HF. © 1990, American Chemical Society. All rights reserved.