Zika virus NS5 RdRp protease binding assay for compound screening using grating-coupled interferometry v1

This protocol aims to measure kinetic parameters (ka, kd, and KD) for compounds against Zika virus (ZIKV) NS5 RdRp protease using the Creoptix Wave system. Grating-coupled interferometry (GCI) is a label-free technique to measure kinetics and affinity for different targets (proteins, small molecules, fragments, etc.) with enhanced sensitivity. Biotin-tagged ZIKV NS5 RdRp protease was captured on the streptavidin-coated chip surface. This immobilisation technique provides oriented and active protein immobilisation for binding assays and can be applied to different protein targets. Binding analysis was performed with the Repeated Analyte Pulses of Increasing Duration (RAPID) method, which involves the injection of samples at a single concentration with varied association times. Kinetic parameters were obtained from the Creoptix Wave software (v 4.5.18) and the in-house developed, open-source, Python-based tool 'SensoFit' (xchem/sensofit).