Effect of Choline Amino Acid‐Based Ionic Liquids on Stability and Structure of Hemoglobin

Abstract

Ionic liquids (ILs) can stabilize or destabilize proteins, which motivates us to examine their effect on hemoglobin. The native state of hemoglobin (Hb) is disrupted at different physical conditions such as pressure, temperature, and solvents. Herein, we have monitored the stability of Hb in a nontoxic and biocompatible IL, i. e., choline amino acid‐based Ils (ChAAILs), using various spectroscopic techniques like UV‐Vis and fluorescence spectroscopy, circular dichroism (CD), and isothermal titration calorimetry (ITC) measurements. It was observed that Hb stays neither in its native state nor in its fully denatured state; rather, it achieves an intermediate state in the presence of ChAAILs. The research on the intermediate state of Hb is still unexplored. Research has been pursued to find a suitable ligand or IL that can stabilize the intermediate state of Hb. In that context, ChAAILs are among the best choices. Molecular docking studies unravel the binding of ChAAILs with Hb. The obtained binding energies of the docked complex are −7.2 kcal/mol and −8.7 kcal/mol for binding of Hb with [Chl][Gly] and [Chl][Met], respectively, which was in line with the ITC results. The quantum chemical calculations show that H‐bond plays a significant role for the interaction between Hb and ChAAILs.

Progress in the applications of biocompatible ionic liquids: renewable commodity production, catalytic and pharmaceutical approaches – a review

“…A remarkable number of recent studies have highlighted that the choline cation can provide a biodegradable and low toxicity Bio-IL. 41–43 Choline, sourced from natural origins, like meat and vegetable, represents one of the B-complex vitamins. 44 Among its numerous functions, such as muscle control and memory, it acts as a precursor to the neurotransmitter acetylcholine.…”

Mechanisms of Biological Effects of Ionic Liquids: From Single Cells to Multicellular Organisms

“…An overview of the protein-related inhibitory potentials of various ILs is given in Table . There are also studies on IL effects on crucial proteins such as myoglobin (see, e.g., refs − ), hemoglobin (see, e.g., , − ), cytochrome c (see, e.g., − ), and serum albumins (see, e.g., , − ), but we intentionally leave them beyond the scope of our consideration due to significant difficulties in relating the observed stabilizing/destabilizing effects to the toxic impact of a given IL on the whole organism.…”