title: Aza-peptides. III. Experimental structural analysis of aza-alanine and aza-asparagine-containing peptides.
abstract: To determine the structural perturbations induced by the C alpha H-->N alpha exchange in aza-peptides, we have examined by 1H NMR and IR spectroscopy various derivatives of the aza-analogues of alanine, aspartic acid and asparagine in different organic solvents with increasing polarity. Their general formulas are: R1-AzXaa-NR2R3, R1-Pro-AzXaa-NR2R3 and R1-AzXaa-Pro-NR2R3 (where AzXaa denotes the aza-analogue of the amino acid residue Xaa = Ala, Asp, Asn; R1 = Boc, Z; R2, R3 = H, Me, iPr). The aza-analogue of an amino acid residue appears to be a strong beta-turn-inducing motif, and the AzAsn carboxamide side-chain is capable of interacting, as a proton donor, with the preceding peptide carbonyl group.
authors.affiliation: LCPM, CNRS-URA-494, ENSIC-INPL, Nancy, France.
authors.forename: F
authors.initials: F
authors.lastname: André
authors.forename: A
authors.initials: A
authors.lastname: Vicherat
authors.forename: G
authors.initials: G
authors.lastname: Boussard
authors.forename: A
authors.initials: A
authors.lastname: Aubry
authors.forename: M
authors.initials: M
authors.lastname: Marraud
mesh_terms: D000409:Alanine / Q000737:chemistry*; D001216:Asparagine / Q000737:chemistry*; D001372:Aza Compounds / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D010455:Peptides / Q000737:chemistry*; D011487:Protein Conformation
chemical_list: D001372:Aza Compounds; D010455:Peptides; D001216:Asparagine; D000409:Alanine