Division of Organic Chemistry, National Institute of Health Sciences, Tokyo 158-8501, Japan.
J Pept Sci. 2010 Mar;16(3):153-8. doi: 10.1002/psc.1213.
One chiral L-valine (L-Val) was inserted into the C-terminal position of achiral peptide segments constructed from alpha-aminoisobutyric acid (Aib) and alpha,beta-dehydrophenylalanine (Delta(Z)Phe) residues. The IR, (1)H NMR and CD spectra indicated that the dominant conformations of the pentapeptide Boc-Aib-DeltaPhe-(Aib)(2)-L-Val-NH-Bn (3) and the hexapeptide Boc-Aib-DeltaPhe-(Aib)(3)-L-Val-NH-Bn (4) in solution were both right-handed (P) 3(10)-helical structures. X-ray crystallographic analyses of 3 and 4 revealed that only a right-handed (P) 3(10)-helical structure was present in their crystalline states. The conformation of 4 was also studied by molecular-mechanics calculations.
一个手性 L-缬氨酸（L-Val）被插入到由α-氨基异丁酸（Aib）和α，β-脱水苯丙氨酸（Δ（Z）Phe）残基构建的非手性肽段的 C 末端位置。IR、（1）H NMR 和 CD 光谱表明，五肽 Boc-Aib-DeltaPhe-（Aib）（2）-L-Val-NH-Bn（3）和六肽 Boc-Aib-DeltaPhe-（Aib）（3）-L-Val-NH-Bn（4）在溶液中的主要构象均为右手（P）3（10）-螺旋结构。3 和 4 的 X 射线晶体学分析表明，它们的晶态中仅存在右手（P）3（10）-螺旋结构。4 的构象也通过分子力学计算进行了研究。
