Pore-containing Helical Structures Constructed By Non-covalent Interactions

In the past several decades,we have witnessed great progress in the understanding of the highly-ordered structures of bio-macromolecules.Currently,it is well-recognized that folding of proteins is the base for their highly-ordered tertiary and quaternary structures and their remarkable functions,such as molecular recognition,transport,electron transfer,and catalysis.In addition,DNA double helix structure carries replication,transcription,translation and other functions,which ensures the normal operation of the life system.It can be seen that the spiral structure plays a vital role in our life system.Inspired by this,scientists have designed the artificial helical structures to simulate the structures and functions of natural helix and develop their applications in chiral separation,sensor,catalysis,transmembrane transport,identification,and optics.Due to the interactions of the helix are divided into covalent and non-covalent,and the spiral structure formed by the non-covalent interaction is close to the natural spiral structure,so it is easier to simulate its functional properties.Therefore,this paper constructs two spiral structures formed by two different non-covalent interactions,and their structures and properties are characterized and explored in detail.1.Design and Synthesis of Self-Folding Helical StructuresThe relative orientation of consecutive units within even a very short oligomer may result in a stable,planar,curved,crescent-like conformation.If its continuous units are added to a certain extent,the electrostatic repulsion of the both ends can lead a self-folding helical structure.We established a new type of aromatic helical oligomers consisting of pyridine as structural motif and 1,3,4-oxadiazole as linker.We have demonstrated that it has a helical conformation in the solution by circular dichroism.2.Design and Preparation of Helical Supramolecular PolymersAt the end of the 20 th century,with the rising and developing of supramolecular chemistry,some people began to try to use supramolecular force to construct the helical structure,and called this kind of spiral structure supramolecular spiral.Compared to the artificial covalent spiral,the supramolecular helix is closer to the natural helix.In this paper,we designed and synthesized a new type of helical structure by using the four hydrogen bonds between molecules,and the assembly morphology in solution are carefully observed and studied by AFM,TEM and SEM.And its principles are also analyzed.3.Channel Properties of Pore-Containing HelicesThe channel properties of the synthesized helical oligomers were tested inspired by the effects of previous work on our group and we found that it can be embed in the phospholipid bilayer by stacking and it is selective only transporting potassium ions,not sodium ions,which implys that it is a good artificial potassium channel.Except for providing attractive models for studying natural channels,the biomimetic K+ channels may also lead to technologically useful applications in medical treatment,desalination,and separation.