We have measured the VCD of polytyrosine in the amide I and I1 regions in dimethyl sulfoxide (DMSO) and in 8020 mixtures of DMSO with trifluoroethanol, trifluoroacetic acid (TFA), and dichloroacetic acid and in 50:50 mixtures of DMSO and trimethyl phosphate (TMP). Additionally, VCD was obtained for
Vibrational circular dichroism of polypeptides. III. Film studies of several α-helical and β-sheet polypeptides
✍ Scribed by A. C. Sen; T. A. Keiderling
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1984
- Tongue
- English
- Weight
- 630 KB
- Volume
- 23
- Category
- Article
- ISSN
- 0006-3525
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✦ Synopsis
Abstract
Vibrational CD (VCD) of amides A, I, and II vibrations of a variety of polypeptide films have been measured. VCD of films of α‐helical and β‐sheet structures are compared in the three regions. Reproducible spectra could only be obtained for thin films free of orientation dependence. The sign and band shape of the VCD of films are not always the same as that in solution. However, the magnitude of the observed VCD seems to correlate with the secondary structure such that α‐helical molecules typically have much larger Δε/ε values than do β‐sheet molecules. The possibility of interference by artifacts owing to light‐scattering effects is discussed.
📜 SIMILAR VOLUMES
We have measured vibrational CD spectra in the 3600-1250 cm-I region of two monodisperse, protected octapeptides, which form right-handed 3,,-helices in CDC13 solution. The spectra are similar in sign pattern to those obtained for right-handed a-helices in solution but are smaller in magnitude and,
## Abstract Vibrational CD (VCD) and ir absorption data are reported for a series of films of Boc‐(L‐Ala)~__n__~‐OMe homo‐oligopeptides (__n__ = 3–7) in the amide I and A regions. The data evidenced a sharp change between __n__ = 3 and __n__ = 4, which parallels the onset of β‐structure formation,