Assessing Binding Perturbation due to Artificial Vibrational Probe Groups in the Nucleoprotein-Phosphoprotein Complex of the Nipah Virus

Abstract

The binding interaction between the intrinsically disordered nucleoprotein tail and the phosphoprotein of the Nipah Virus (NiV) involves both disorder-to-order transition and fuzzy binding. To examine the dynamic structure and the conformational distribution of this interaction, a site-specific thiocyanate (SCN) vibrational probe was incorporated at many sites on the binding region of the NiV NTAIL. Since this binding is likely driven by hydrophobic forces, replacing a non-polar amino acid side chain with a polar probe could perturb binding. Isothermal titration calorimetry (ITC) experiments were designed to determine the extent of disruption to binding thermodynamics. The ITC results were then used to inform the interpretation of the vibrational spectroscopy data and measure the importance of single amino acids in maintaining this “fuzzy” binding interface.