Professor Mihail barboiu and doctoral student Zheng Shaoping, foreign tutor of Sun Yat sen University, reported the first novel biomimetic ion transport channel based on the coordinated regulation of hydrogen bond and anion π interaction

It is a common physiological phenomenon that ions migrate across membrane by protein channels Its existence not only maintains the normal homeostasis of cells, but also forms the basis of electrical signal transmission inside and outside cells If the transmission process is blocked, or the structural defect of protein channel is caused by gene mutation, a series of physiological problems will be caused, which are called "channel diseases" in medicine, such as Bart syndrome, bester's disease, cystic fibrosis and other typical clinical diseases Compared with the traditional modification methods of defective proteins, the direct synthesis of biomimetic channels with ion transport function has become a popular new anti-cancer treatment method At present, most of the biomimetic ion channels are constructed by the following assembly strategy: design a channel with multiple ion binding sites (the binding direction is pointing to the center of the channel) As a structural element, through the regulation of the strength of supramolecular action, we selectively combine the target ion, and skillfully make the ion leap forward in a certain direction, forming a channel structure for free transport of ions In this paper, the supramolecular interactions involved mainly refer to various forms of hydrogen bonds, including classical hydrogen bonds, C-H bonds, anion dipole interactions, etc., while others, such as anion π interactions, have been widely reported to exist between the host and guest based on anion recognition, but they are extremely rare in biological transport channels, and only in the form of ion transport carriers Recently, Professor Mihail barboiu and doctoral student Zheng Shaoping, an expert in the "Thousand Talents Program" of Lehn Institute of functional materials, School of chemistry, Sun Yat sen University, reported the first anion transport channel based on the coordinated regulation of hydrogen bond and anion - π interaction In terms of structure, after protonation of four molecules on the same plane, through coordination of various hydrogen bonds (hydrogen bond sources include - ch on triazole ring, - NH 2, and - NH adjacent to amide bond of five membered ring), a pair of triazole quadrupole moment T 4 structure can be formed, which can stabilize the existence of a pair of anions; at the same time, the anions are located on the plane or (and ）The lower triazole ring has a strong anion - π effect (3.2-3.7 Å), which makes it finally form a transport path for anion to slip through (figure left) In this transport structure, the free pore can allow anions of 3-4 Å to pass through, and the slip length is 9-10 Å Generally speaking, molecular protonation is the premise (molecules without protonation can only form a network structure of hydrogen bond complexation), anion π interaction provides the power of ion pair sequential sliding, while the hydrophobic alkyl chain at the outer end acts as a protective shell to guarantee the stable existence of the whole channel structure in the water environment These three points are the successful construction of the anion transport There are three essential elements in the channel structure Next, based on the fluorescence transport experiment of vesicle membrane, the author compared the ion transport performance of different size protonated molecules self-assembled on the phospholipid membrane to form the channel structure, and speculated its ion transport mechanism (figure right) As the only way to distinguish the construction form of ion transport carrier or ion transport channel, patch clamp experiment helps to confirm the existence of the channel structure on the phospholipid membrane All of these will open up new ideas and provide reference for the further design of a new bionic ion transport channel with high efficiency ion selective transport Anion channel (left) and its formation process (middle) and ion transport mechanism (right) (source: School of chemistry, Sun Yat sen University) This work was recently published in the scientific journal "Shao Ping Zheng and Mihail barboiu *, Angel Chem Int ed 2019, DOI: 10.1002/anie.201904808), and was listed as one of the VIP (very important paper, 5%), and was selected as the back cover article of the current journal This research is supported by the national foundation of China, the National Research Institute of France and Lehn Institute of functional materials.