2.6. Surface plasmon resonance assay
The interactions between SARS-CoV-2 Mpro and gallic
acid and quercetin for were studied by SPR include immobilizing
SARS-CoV-2 Mpro on a CM5 sensor chip surface and then
flowing a solution containing the compound over the surface. The sensor
surface was activated with a 7 min injection of the mixture of 50 mM
N-hydroxysuccinimide (NHS) and 200 mM 1-ethyl-3-(3-dimethylaminopropyl)
carbodiimide (EDC). 10 mM sodium acetate was used as a running buffer.
Compounds was diluted to different concentrations and injected over the
surfaces at a flow rate of 10 µL/min. The contact time was 90 s,
followed by a 180 s dissociation period. All SPR experiments were
conducted on Biacore T200 instruments (Cytiva, Sweden). The specific
experimental protocol and conditions were performed as described in
previous study28,29.