Temperature-dependent hydration behavior of aqueous lysine: an approach towards protein binding through dielectric spectroscopy

Present work reports interaction between water and amino acid lysine for understanding the physicochemical properties that will be useful in the structure formation of protein. The dielectric relaxation of aqueous lysine was systematically investigated over a temperature range spanning from 298.15 K to 278.15 K, encompassing frequencies ranging from 10 MHz to 30 GHz, and across a concentration range of 0.152 M to 0.610 M. Within this study, aqueous lysine revealed the presence of two distinct relaxation modes. The low-frequency relaxation process (l-process) is primarily associated with the relaxation of lysine molecules, whereas the high-frequency relaxation process (h-process) is attributed to water molecules interacting with lysine. Several key dielectric parameters, including static dielectric constant (epsilon j), relaxation time (tau j), dipole moment (mu j), correlation factor (gj), and the number of water molecules rotationally bonded by solute molecules (Zib), were meticulously determined. These parameters were interpreted in terms of molecular interactions, hydrogen bonding, hydrophobicity, and Lys-Lys binding. Additionally, various thermodynamic parameters such as molar enthalpy (Delta Hj), molar entropy (Delta Sj), and molar free energy (Delta Fj) were calculated to provide further insights into the system's characteristics and behavior.Communicated by Ramaswamy H. Sarma

Automated summary

This study investigates the interaction between water and the amino acid lysine in order to understand the physicochemical properties that contribute to protein structure formation. The research reveals the presence of two distinct relaxation modes in aqueous lysine and provides detailed analysis of key dielectric and thermodynamic parameters. The findings shed light on molecular interactions, hydrogen bonding, hydrophobicity, and Lys-Lys binding.