Use of Ionic Liquids in Protein and DNA Chemistry

Abstract

Ionic liquids (ILs) have been receiving much attention as solvents in various areas of biochemistry because of their various beneficial properties over the volatile solvents and ILs availability in myriad variants (perhaps as many as 108) owing to the possibility of paring one cation with several anions and vice-versa as well as formulations as zwitterions. Their potential as solvents lies in their tendency to offer both directional and non-directional forces toward a solute molecule. Because of these forces, ionic liquids easily undergo intermolecular interactions with a range of polar/non-polar solutes, including biomolecules such as proteins and DNA. The interaction of genomic species in aqueous/non-aqueous states assists in unraveling their structure and functioning, which have implications in various biomedical applications. The charge density of ionic liquids renders them hydrophilic and hydrophobic, which retain intact over long-range of temperatures. Their ability in stabilizing or destabilizing the 3D-structure of a protein or the double-helical structure of DNA has been assessed superior to the water and volatile organic solvents. The aptitude of an ion in influencing the structure and stability of a native protein depends on their ranking in the Hofmeister series. However, at several instances, a reverse Hofmeister ordering of ions and specific ion-solute interaction has been observed. The capability of an ionic liquid in terms of the tendency to promote the coiling/uncoiling of DNA structure is noted to rely on the basicity, electrostatic interaction, and hydrophobicity of the ionic liquid in question. Any change in the DNA's double-helical structure reflects a change in its melting temperature (Tm), compared to a standard buffer solution. These changes in DNA structure have implications in biosensor design and targeted drug-delivery in biomedical applications. In the current review, we have attempted to highlight various aspects of ionic liquids that influence the structure and properties of proteins and DNA. In short, the review will address the issues related to the origin and strength of intermolecular interactions, the effect of structural components, their nature, and the influence of temperature, pH, and additives on them.

An experimental approach probing the conformational transitions and energy landscape of antibodies: a glimmer of hope for reviving lost therapeutic candidates using ionic liquid

“…[15][16][17][DHP] has also been found to signicantly stabilise DNA and nuclease and to increase protein thermal and storage stability via hydrogen bonding and electrostatic interactions. 15,18 Thus, we are particularly interested in understanding the effects of biocompatible ILs, specically [Cho][DHP], on protein stability and the energy landscape and conformational transitions of functional proteins.…”

Influence of Alkyl Chain Length on Thermal Properties, Structure, and Self-Diffusion Coefficients of Alkyltriethylammonium-Based Ionic Liquids

“…Even though a vast number of works on the structure and properties of ionic liquids are present in the literature, experimental as well as theoretical studies are needed on this topic, especially considering those ILs that are less often used and more environmentally benign, e.g., ammonium, diazolium/triazolium, or nature-inspired ILs [ 4 , 8 , 9 ]. Two of the most widely explored groups of ILs are imidazolium and pyridinium [ 10 , 11 ].…”

Enhancement of the Catalytic Activity of Hammerhead Ribozymes by Organic Cations

“…It is known that salts of bulky organic cations, including quaternary ammonium, phosphonium, and pyridinium ions, can form ionic liquids soluble in aqueous solution. [25] Our results imply that some ionic liquid compounds have the potential to enhance the catalytic activity of hammerhead ribozymes. Additionally, it is mentioned that living cells contain many types of bulky cationic molecules, including basic proteins.…”