Conformational Preferences of Peptides Containing Reverse-Turn Mimetic Bicyclic Lactams: Inverse γ-Turns versus Type-II′ β-Turns – Insights into β-Hairpin Stability
✍ Scribed by Laura Belvisi; Cesare Gennari; Antonia Mielgo; Donatella Potenza; Carlo Scolastico
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 271 KB
- Volume
- 1999
- Category
- Article
- ISSN
- 1434-193X
No coin nor oath required. For personal study only.
✦ Synopsis
The solid-phase synthesis and characterization of a series of of the reverse-turn mimic. In N-acetylated tetrapeptide mimics incorporating the two different bicyclic lactams (a peptides (3-9), containing reverse-turn mimetic bicyclic lactams (1a, 1b), was reported in the preceding paper. The series and b series), H 5 is available for either a γ-turn (7membered ring with the carbonyl group of the bicyclic bicyclic lactams (1a, 1b) possess high structural similarity to the two central residues of a β-turn. The conformational lactam) or a β-turn (10-membered ring with the carbonyl group of residue 2), as shown in Figures 7 and9. The a series preferences of the constrained peptides have been investigated by NMR spectroscopy and IR spectroscopy. Our incorporating the (5,7)-bicyclic lactam predominantly induces the γ-turn conformation, while the b series experimental results have been complemented by computer modelling studies and show that the constrained peptides (3-incorporating the (5,6)-bicyclic lactam can promote either a γ-turn or a β-turn conformation, with the β-turn usually being 9) form an inverse γ-turn or a type-IIЈ β-turn through intramolecular hydrogen bonding, depending on the nature preferred and with varying degrees of β-hairpin formation.