Department of Organic Chemistry Ugo Schiff, University of Florence, Via della Lastruccia 13, I-50019, Sesto Fiorentino (FI), Italy.
Org Biomol Chem. 2010 Feb 21;8(4):916-24. doi: 10.1039/b913444a. Epub 2009 Dec 14.
Four peptides differing for the structure of the new morpholine-based heterocyclic compound acting as a turn inducer were synthesized in solution phase, and the conformational preferences were assessed by means of NMR analysis. All spectroscopic data revealed an adaptive behaviour of the turn peptides in generating turn conformations stabilized by intramolecular hydrogen-bonds, despite the conformational changes of the turn inducer. Thus, this study suggests the possibility of functionalizing morpholine-containing beta-turn peptides with no significant loss of the secondary framework. The 3,4-dihydro-2H-[1,4]oxazine-containing peptide showed a more compact structure stabilized by an additional gamma-turn-forming hydrogen-bond experienced by the Gly amide proton.
四种不同结构的肽在溶液相中被合成，这些肽都含有新型吗啉基杂环化合物作为诱导物，通过 NMR 分析评估其构象偏好。所有的光谱数据都表明，尽管诱导物的构象发生了变化，但这些转角肽通过形成分子内氢键来稳定转角构象，从而表现出适应性行为。因此，这项研究表明，有可能在不显著损失二级结构的情况下，对含有吗啉的β-转角肽进行功能化。含有 3,4-二氢-2H-[1,4]恶嗪的肽具有更紧凑的结构，由甘氨酸酰胺质子经历的额外的γ-转角形成氢键稳定。
