Interaction between arginine conformers and Hofmeister halide anions

In this work, we investigated the interaction between halide anions with arginine conformers in an attempt to identify the suitable halide anion to suppress the protein aggregation. The result obtained from structural parameters reveals that the interaction of halide anions results in salting out property of arginine and decreases in the order F- > Cl- > Br-. On a macromolecular perspective, the interaction of halide anions at the amide position leads to interaction of the guanidinium site of the arginine to interact with the hydrophobic core of the protein, which subsequently slows down the protein-protein aggregation. The halide ion size regulates the preferential binding sites in protein and decreases the rate of association by several orders of magnitude i.e. through size of the ion. The radial distribution plot (RDF) plotted between the various pairs, shows that the fluoride anion has more affinity towards the arginine in first hydration shell. (C) 2016 Elsevier B.V. All rights reserved.