Cation−Π Interactions in Biochemistry: A Primer

Abstract

Although the potent effects of cation−π interactions for stabilizing protein structure and binding ligands to proteins have been reported in the chemical literature for over two decades, there are no undergraduate biochemistry textbooks covering this important noncovalent attractive force. In an attempt to remedy this situation, this primer describes what cation−π interactions are, provides biochemical examples of cation−π interactions that supplement the protein structure and ligand binding topics of a traditional one-semester biochemistry course, and offers exercises and worked out solutions on cation−π interactions derived from the biochemical literature. In addition, instructions are provided for using the online molecular visualization tools FirstGlance and JSmol viewer to identify cation−π interactions in proteins and for calculating cation−π stabilization energy with the online CaPTURE program.

Quantitative determination of cation–π interactions between metal ions and aromatic groups in aqueous media by a hydrogel Donnan potential method

“…Cation–π interactions are noncovalent molecular interactions between the face of an electron-rich π system and an adjacent cation, known to exist widely in biological systems and play critical roles in various physiological activities, such as molecular recognition, protein folding, and enzyme catalysis, among others. 1–5 For instance, metal ions can interact with the aromatic residues of proteins through cation–π interactions. Understanding these interactions in various aqueous environments is a prerequisite for elucidating the physical mechanism of their biological functions.…”

Constructing a shape memory network with controllable stability and dynamic features through cation–π interactions

“…Recently, the cation-π interaction has attracted our attention due to its high stability in bulk materials and good reversibility in suitable chemical environments. It was first identified in protein multistage structures, 27,28 and now it has been widely applied in adhesion, [29][30][31] self-assembled structures, 32,33 surface modification 34 and metal adsorption. 35 It is essentially an electrostatic interaction that occurs between the cation and electronrich π orbitals, 36 where the bond energy of the cation-π interaction can be strong and adjustable due to its various structures.…”

Green Fischer Indole Synthesis Using a Steroidal Ketone in a Conductively Heated Sealed-Vessel Reactor for the Advanced Undergraduate Laboratory

“…A search in this journal alone for heterocyclic synthesis yields well over 700 results. The indole heterocycle is prominent in a wide variety of alkaloids with important pharmacologic properties, but only a few undergraduate synthetic experiments or other activities centering on indoles have been described in this journal …”