André F, Vicherat A, Boussard G, Aubry A, Marraud M
LCPM, CNRS-URA-494, ENSIC-INPL, Nancy, France.
J Pept Res. 1997 Nov;50(5):372-81. doi: 10.1111/j.1399-3011.1997.tb01197.x.
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.
为了确定氮杂肽中CαH→Nα交换引起的结构扰动，我们通过1H NMR和红外光谱研究了丙氨酸、天冬氨酸和天冬酰胺的氮杂类似物在极性不断增加的不同有机溶剂中的各种衍生物。它们的通式为：R1-AzXaa-NR2R3、R1-Pro-AzXaa-NR2R3和R1-AzXaa-Pro-NR2R3（其中AzXaa表示氨基酸残基Xaa = Ala、Asp、Asn的氮杂类似物；R1 = Boc、Z；R2、R3 = H、Me、iPr）。氨基酸残基的氮杂类似物似乎是一种强烈的β-转角诱导基序，并且AzAsn羧酰胺侧链能够作为质子供体与前面的肽羰基相互作用。
