Vibrational circular dichroism of polypeptides. II. Solution amide II and deuteration results

✍ Scribed by A. C. Sen; T. A. Keiderling

• Publisher: Wiley (John Wiley & Sons)
• Year: 1984
• Tongue: English
• Weight: 708 KB
• Volume: 23
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.360230808

✦ Synopsis

Synopsis

Vibrational CD (VCD) of amide I and I1 vibrations of several a-helical polypeptides have been measured in solution. For the amide I1 as well as the amide I [previously published: Lal, B.B. & Nafie, L.A. (1982) Biopolymers 21, 21611 we find the VCD to be characteristic of the polypeptide secondary structure. Amide I1 bands of right-handed u helices were all found to have negative VCD and to have their maximum rotational strength for the parallel (low-energy) component. However, left-handed a helices formed from L-amino acids gave positive amide I1 bands at higher frequencies than found for the right-handed helices, indicating that the VCD was sensitive to the stereochemical difference. The amide-I VCD spectra of some deuterated right-handed a-helical polypeptides have a new negative feature to low frequency that does not reflect theoretical predictions but also appears to be stereochemically sensitive. Amide-I1 and amide-A VCD of a few deuterated polypeptides imply retention of the secondary-structure-dependent characteristics seen in the hydrogenated VCD.