The spectral shifts of SPR (Surface Plasmon Resonance) band of gold nano-colloids were utilized to investigate the affinity of the SARS-CoV-2 spike protein (S protein) to gold nano-colloids’ surfaces. The SPR band peak shift was examined as the pH values were hopped between pH ~3 and pH ~10, and an alternation of the average SPR band peaks were observed. For the diameter of gold larger than 30 nm, a significant amplitude of an alternation was observed under the presence of the S proteins. It implies that the reproduction of pH induced reversible protein folding of an S protein. We interpret that the folded conformation was formed at pH <u>&gt;</u> ~7 and the unfolded conformation was maximized at pH ~3 and the lower. The folded conformation may correspond to the down conformation of RBD (receptor binding domain), and the unfolded conformation may correspond to the up conformation of RBD. The formation of the gold nano-particle aggregates could be due to the interaction between the S proteins with up conformation. We concluded that gold nano-colloidal particles are sensitive to the conformational change of the protein adsorbed over the particles’ surface.

Spectroscopic studies on the affinity of SARS-CoV-2 spike proteins to gold nano-colloids

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.