Saturation transfer differences (STD) NMR is not only a method for drug discovery and screening, but also has qualitative and quantitative applications that can answer questions involving molecular interactions between ligands and proteins, in particular to obtain dissociation constants from STD NMR titrations. The STD NMR experiment has proved to be a powerful tool for studying ligand binding to native viruses or virus-like particles (VLPs). Creative Biostructure provides the STD NMR service to characterize the binding epitopes of ligands and their target proteins or VLPs involved in coronavirus research.