Infrared and Raman study in the solid state of fully protected, monodispersed homooligopeptides of L-valine, L-isoleucine, and L-phenylalanine

✍ Scribed by M. H. Baron; C. De Loze; C. Toniolo; G. D. Fasman

• Publisher: Wiley (John Wiley & Sons)
• Year: 1979
• Tongue: English
• Weight: 673 KB
• Volume: 18
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.1979.360180216

✦ Synopsis

Abstract

An ir‐absorption and Raman‐scattering study, in the solid state, has been carried out on monodispersed, N‐ and C‐protected homooligopeptides (number of residues, n, from 2 to 7) of L‐valine, L‐isoleucine, and L‐phenylalanine. The amide I, II, III, V, and __v__NH regions have been examined. Some deuterated (ND) samples have been examined to complete the assignments. L‐Phenylalanine dipeptide displays spectral characteristics compatible with the parallel β‐structure; L‐isoleucine and L‐valine dipeptides are probably in a distorted structure. A mixture of parallel and antiparallel extended chains cannot be excluded for the peptides with n = 3. In the amide I region the spectra of peptides with n ≥ 4 show the existence of the β‐conformation. The problem of chain orientation within the pleated‐sheet structure is discussed on the basis of a recent theoretical treatment of vibrational interactions of the amide I mode.