The proline residue of dipeptides Ser-Pro and Pro-Ser has been replaced by 7-azabicyclo[2.2.1]heptane-1-carboxylic acid (Ahc), a conformationally restricted analogue of proline that is capable of mimicking distorted amides. The conformational analysis of the new peptides in the solid state revealed that the Ahc-Ser sequence displays a type I beta-turn, which includes a distorted amide bond. In contrast
二肽Ser-Pro和Pro-Ser的脯
氨酸残基已被
7-氮杂双环[2.2.1]庚烷-1-
甲酸(Ahc)取代,这是脯
氨酸的构象受限类似物,能够模拟扭曲的酰胺。对固态新肽的构象分析表明,Ahc-Ser序列显示出I型β-转角,其中包括一个扭曲的酰胺键。相反,Ser-Ahc序列以非折叠结构存在。