Crystallographic characterization of the α ,γ C12 helix in hybrid peptide sequences
| Autor: | Madhusudana M. B. Reddy, Padmanabhan Balaram, Subrayashastry Aravinda, Krishnayan Basuroy |
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| Rok vydání: | 2016 |
| Předmět: |
Pharmacology
chemistry.chemical_classification 010405 organic chemistry Hydrogen bond Organic Chemistry Peptide General Medicine Dihedral angle 010402 general chemistry 01 natural sciences Biochemistry 0104 chemical sciences Crystallography chemistry Structural Biology 310 helix Intramolecular force Drug Discovery Helix Atom Molecular Medicine Molecular Biology Polyproline helix |
| Zdroj: | Journal of Peptide Science. 22:504-510 |
| ISSN: | 1075-2617 |
| Popis: | The solid-state conformations of two αγ hybrid peptides Boc-[Aib-γ(4) (R)Ile]4 -OMe 1 and Boc-[Aib-γ(4) (R)Ile]5 -OMe 2 are described. Peptides 1 and 2 adopt C12 -helical conformations in crystals. The structure of octapeptide 1 is stabilized by six intramolecular 4 → 1 hydrogen bonds, forming 12 atom C12 motifs. The structure of peptide 2 reveals the formation of eight successive C12 hydrogen-bonded turns. Average backbone dihedral angles for αγ C12 helices are peptide 1, Aib; φ (°) = -57.2 ± 0.8, ψ (°) = -44.5 ± 4.7; γ(4) (R)Ile; φ (°) = -127.3 ± 7.3, θ1 (°) = 58.5 ± 12.1, θ2 (°) = 67.6 ± 10.1, ψ (°) = -126.2 ± 16.1; peptide 2, Aib; φ (°) = -58.8 ± 5.1, ψ (°) = -40.3 ± 5.5; ψ(4) (R)Ile; φ (°) = -123.9 ± 2.7, θ1 (°) = 53.3 θ 4.9, θ 2 (°) = 61.2 ± 1.6, ψ (°) = -121.8 ± 5.1. The tendency of γ(4) -substituted residues to adopt gauche-gauche conformations about the C(α) -C(β) and C(β) -C(γ) bonds facilitates helical folding. The αγ C12 helix is a backbone expanded analog of α peptide 310 helix. The hydrogen bond parameters for α peptide 310 and α-helices are compared with those for αγ hybrid C12 helix. Copyright © 2016 European Peptide Society and John Wiley & Sons. |
| Databáze: | OpenAIRE |
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