Nmr studies of a free and protected tetrapeptide glycyl-L-prolylglycylglycine in β-turn-supporting environment
✍ Scribed by B. Perly; N. Helbecque; A. Forchioni; M. H. Loucheux-Lefebvre
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1983
- Tongue
- English
- Weight
- 744 KB
- Volume
- 22
- Category
- Article
- ISSN
- 0006-3525
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✦ Synopsis
Nmr studies of the protected and free tetrapeptide Gly-Pro-Gly-Gly were carried out in 8-turn-supporting solvents, that is, in CDCl3 for Z-Gly-Pro-Gly-Gly-OMe and in MezSO-dG for H-Gly-Pro-Gly-Gly-OH. Comparisons with specifically a-deuterated analogs gave complete assignments of the NH and methylene regions. Analysis of chemical shifts, coupling constants, and the temperature dependence of chemical shifts show that the peptide adopts a type I1 @-turn conformation. This turn is stabilized for the protected tetrapeptide by two hydrogen bonds between (i) C = O (Glyl) and NH(GIy,), and (ii) urethane function NH and methyl ester C=O.