Pantano M, Formaggio F, Crisma M, Bonora G M, Toniolo C, Aubry A, Bayeul D, Dautant A, Précigoux G, Boesten W H
Biopolymer Research Center, C.N.R. Department of Organic Chemistry, University of Padova, Italy.
Pept Res. 1993 Jul-Aug;6(4):196-204.
We have synthesized by solution methods and fully characterized a variety of (alpha Me)Leu/Aib model peptides to the octapeptide level. A solution conformational analysis was performed by using infrared absorption. 1H nuclear magnetic resonance, and circular dichroism. The crystal-state structures of Z-D-(alpha Me)Leu-(Aib)2-OtBu, pBrBz-(Aib)2-D-(alpha Me)Leu-(Aib)2-OtBu, and Ac-(Aib)2-D-(alpha Me)Leu-(Aib)2-OtBu monohydrate were solved by x-ray diffraction. The results indicate that the (alpha Me)Leu residue may be easily incorporated into beta-bends and 3(10)-helical structures, and suggest that this residue tends to induce a helix handedness opposite to that promoted by its unmethylated counterpart (Leu) of the same optical configuration.
我们已通过溶液法合成了多种（α-甲基）亮氨酸/氨基异丁酸（Aib）模型肽，并对其至八肽水平进行了全面表征。利用红外吸收、¹H核磁共振和圆二色性进行了溶液构象分析。通过X射线衍射解析了Z-D-（α-甲基）亮氨酸-（Aib）₂-OtBu、对溴苯甲酰基-（Aib）₂-D-（α-甲基）亮氨酸-（Aib）₂-OtBu和Ac-（Aib）₂-D-（α-甲基）亮氨酸-（Aib）₂-OtBu一水合物的晶体结构。结果表明，（α-甲基）亮氨酸残基可能易于并入β-转角和3（10）-螺旋结构，并表明该残基倾向于诱导与其相同光学构型的未甲基化对应物（亮氨酸）所促进的螺旋手性相反的螺旋手性。
