Rich D H, Kawai M, Jasensky R D
Int J Pept Protein Res. 1983 Jan;21(1):35-42.
The conformations of chlamydocin and cyclo (Ala-Aib-Phe-D-Pro) (Ala4-chlamydocin) in chloroform have been investigated by nuclear magnetic resonance, infrared and circular dichroism spectroscopy. The data obtained from these experiments establish an all transoid, bis gamma-turn conformation for both compounds in chloroform with the following torsional angles (+/- 20 degrees): Ala4-chlamydocin: Aib, phi + 60 degrees, psi - 50 degrees; omega + 160 degrees; Phe phi - 120 degrees, psi + 120 degrees, omega - 160 degrees; D-Pro phi + 60 degrees, psi - 55 degrees, omega + 160 degrees; Ala phi - 110 degrees, psi + 110 degrees, omega - 160 degrees. Chlamydocin adopts a closely related conformation in neat chloroform. Nuclear Overhauser Effect (NOE) data are utilized to assign amide bond geometries in the cyclic tetrapeptide ring system.
通过核磁共振、红外光谱和圆二色光谱对氯仿中衣原体毒素和环（丙氨酸-氨基异丁酸-苯丙氨酸-D-脯氨酸）（丙氨酸4-衣原体毒素）的构象进行了研究。从这些实验中获得的数据确定了两种化合物在氯仿中的全反式、双γ-转角构象，其扭转角如下（±20度）：丙氨酸4-衣原体毒素：氨基异丁酸，φ +60度，ψ -50度；ω +160度；苯丙氨酸φ -120度，ψ +120度，ω -160度；D-脯氨酸φ +60度，ψ -55度，ω +160度；丙氨酸φ -110度，ψ +110度，ω -160度。衣原体毒素在纯氯仿中采用密切相关的构象。利用核Overhauser效应（NOE）数据确定环四肽环系统中的酰胺键几何结构。
