6533b7dbfe1ef96bd1270c06

RESEARCH PRODUCT

Thecis-transisomerization ofN-methyl-α,β-dehydroamino acids

Dawid SiodłakAgnieszka Macedowska-capigaMałgorzata A. BrodaAnna E. KoziolTadeusz Lis

subject

Models MolecularAcetonitrilesMagnetic Resonance SpectroscopyStereochemistryMolecular ConformationBiophysicsStereoisomerismCrystallography X-RayBiochemistryBiomaterialschemistry.chemical_compoundAmideSpectroscopy Fourier Transform InfraredPeptide bondchemistry.chemical_classificationOrganic ChemistryStereoisomerismGeneral MedicineNuclear magnetic resonance spectroscopyAmidesCis trans isomerizationCyclic peptidechemistryChloroformPeptidesAcidsIsomerizationCis–trans isomerism

description

Dehydroamino acids with the methylated N-terminal peptide group occur in natural small cyclic peptides. The structural analysis was used to investigate the cis-trans isomerization of the N-terminal tertiary amide group of diamides: Ac-(Z)-Δ(Me)Abu-NHMe (1), Ac-(Z)-Δ(Me)Phe-NHMe (2), Ac-(E)-Δ(Me)Phe-NHMe (3), Ac-Δ(Me)Ala-NHMe (4), and Ac-(Me)Ala-NHMe (5). The compounds were analyzed in the solid state by an X-ray crystallography (1-3), and in the solution by FTIR (MeCN and CHCl(3) ) and NMR (DMSO-d6 and CDCl(3) ) methods (1-5). In the solid state, the studied compounds adopt the cis configuration of N-terminal amide. In solution, this configuration also prevails for the dehydroamino acids 1-4, in contrast to the saturated analog 5. The results indicate that N-methyldehydroamino acids present a promising tool to induce the cis configuration of the amide bond.

yearjournalcountryeditionlanguage
2012-01-28Biopolymers
https://doi.org/10.1002/bip.22082