Preferred structures of constrained peptides from achiral α,α-dialkyiated glycyl residues with acyclic side chains.
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Date
1985-08
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Abstract
Conformational energy computations of the monopeptides from three achiral α,α−
dialkylated glycyl residues with acyclic side chains (namely α,α-dimethyl-; α,α−diethyl-; and a, adi-
n-propylglycines) are reported as a function of the relevant N-Cα-C' bond angle. In parallel,
experimental studies were performed in the solid state (infrared absorption and X-ray
diffraction) and in solution (infrared absorption and proton magnetic resonance) on the
corresponding protected homo-peptide series (the former series to the dodecamer, the other
two series to the pentamers). The results obtained unequivocally indicate that the preference
from a helical to a fully extended conformation increases as side-chain bulkiness increases. The
longest homo-peptides from α,α−dimethylglycine form stable 310-helices. A picture of the
mode of self-association of the helical structures has also been determined. The results of the
theoretical analyses fit well with the experimentally observed conformational properties in the
solid state and in chloroform solution.
Description
Keywords
α,α-Dialkylated amino acids, α−aminoisobutyric acid, infrared spectroscopy, NMR spectroscopy, peptide conformation, X-ray diffraction
Citation
Benedetti E, Blasio B Di, Pavone V, Pedone C, Vavoso A, Toniolo C, Bonora G M, Leplawy M T, Hardy P M. Preferred structures of constrained peptides from achiral α,α-dialkyiated glycyl residues with acyclic side chains. Journal of Biosciences. 1985 Aug; 8(1&2): 253-262.