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它生物活性化合物 是环肽。 具有确定骨架的合成环肽 构象是潜在的有用的类似物，用于确定生物 天然肽的活性构象。 构象 环化作用的限制使环肽成为极好的模型 蛋白质构象的研究。 许多环肽 也参与离子穿过生物膜的运输。 x射线 晶体学是一个很好的工具，以确定构象特征， 环肽 分子的构象与 其生物活性及环状构象的研究 不同条件下结晶的肽及其比较 结果与其他方法，如光谱法， 技术将是非常有价值的。 本课题利用X射线衍射技术， 一些合成环肽， 可用作生物活性分子的类似物和金属的研究 环肽的离子络合物， 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.