CYCLIC PEPTIDES, STRUCTURE, AND FUNCTION

一大类天然存在的化合物，如抗生素、毒素、 激素、离子转运调节剂和其他生物活性化合物 都是环肽。人工合成具有明确骨架的环肽 构象作为类似物在生物学上确定可能是有用的 天然多肽的活性构象。构象 环化限制使环肽成为极好的模型 用于研究蛋白质构象的化合物。许多环肽 还参与了离子在生物膜上的运输。X射线 结晶学是确定构象特征的一个很好的工具 环肽。分子的构象与 其生物活性及其环状构象的研究 不同条件下结晶的多肽及其活性比较 结果与其他方法得到的结果，如光谱 技术将是非常有价值的。 在本项目中，使用X射线衍射技术检测了 几种人工合成的环肽的结构和构象 用作生物活性分子和金属研究的类似物 对理解离子有帮助的环肽离子络合物 计划了跨生物膜的运输机制。

A large class of naturally occurring compounds like antibiotics, toxins, hormones, ion transport regulators and other biologically active compounds are cyclic peptides. Synthetic cyclic peptides of defined backbone conformation are potentially useful as analogs for determining biologically active conformations of naturally occurring peptides. The conformational restrictions imposed by cyclisation make cyclic peptides excellent model compounds for the study of the protein conformation. Many cyclic peptides also take part in the transport of ions across biological membranes. X-ray crystallography is a fine tool to determine the conformational features of cyclic peptides. The conformation of a molecule is intimately related to its biological activity and the study of the conformation of cyclic peptides crystallized under different conditions and comparison of the results with those obtained from other methods such as spectroscopic techniques would be very valuable. In this project using X-ray diffraction technique the examination of the structure and conformation of a few synthetic cyclic peptides which are useful as analogs for biologically active molecules and the study of metal ion complexes of cyclic peptides which are useful in understanding the ion transport mechanism across the biological membrane are planned.