Peptide-mediated conformational changes in bilipeptides: evidence for the occurrence of stretched species
作者:Daniel Krois、Harald Lehner
DOI:10.1039/p29900001745
日期:——
Flexible biliverdins covalently bound to tripeptides of the sequence Pro-X-Y exhibit a remarkable tendency to adopt stretched conformations. This contrasts with the behaviour of the great many bilipeptides synthesized so far, preserving the (Z,Z,Z,syn,syn,syn) geometry. The conformational changes induced are strongly solvent dependent and sensitive to the steric requirements of the amino acid constituent
与序列Pro-XY的三肽共价结合的柔性biliverdins表现出明显的采用伸展构象的趋势。这与迄今为止合成的许多双脂肽的行为相反,保留了(Z,Z,Z,syn,syn,syn) 几何学。诱导的构象变化强烈依赖溶剂,并且对氨基酸成分X的空间要求敏感。在携带两个肽实体非常接近的biliverdin bis(三肽)中,后者的影响被分子内肽与肽的链间相互作用所叠加。在这些情况下,仅当氨基酸实体X变得更大时,发色团才发生拉伸。构象变化是通过围绕C(5)次甲基单键旋转而进行的,因此形成了(Z,Z,Z,anti,syn,syn)。Pro-XY肽酯在氢键差的溶剂中有利于拉伸构象异构体的出色行为归因于γ弯曲的形成。结论是对18种Biliverdin肽的UV-VIS,CD和1 H NMR光谱进行综合评估得出的,这些肽包括构象上可移动的和刚性的双三烯生色团。