Nano-size dependent protein corona formation by SARS-CoV-2 Omicron spike protein over gold nano-colloid and reversible aggregation

Kazushige Yokoyama; Theresa Lam; Jack Santariello; Akane Ichiki

doi:10.1016/j.colsurfa.2022.128967

Nano-size dependent protein corona formation by SARS-CoV-2 Omicron spike protein over gold nano-colloid and reversible aggregation

Colloids Surf A Physicochem Eng Asp. 2022 Aug 20:647:128967. doi: 10.1016/j.colsurfa.2022.128967. Epub 2022 Apr 16.

Authors

Kazushige Yokoyama¹, Theresa Lam¹, Jack Santariello¹, Akane Ichiki¹

Affiliation

¹ Department of Chemistry, The State University of New York Geneseo College, Geneseo, NY, USA.

Abstract

The adsorption process of SARS-CoV-2 Omicron spike protein to the nano-gold colloid surfaces was examined by monitoring the surface plasmon resonance (SPR) band shift of gold-nano particles ranging between diameters of d = 10-100 nm. The externally changed pH between 3 and 11 at 24.5 ± 0.4 °C initiated a reversible formation of the gold colloid aggregates, where formation/deformation of the aggregates were monitored by red/blue shift of the peak of the SPR band. There was no sign of reversible aggregation for d = 10, 15, and 20 nm gold colloids. A clear undulation of the peak shift corresponding to pH hopping between pH ~3 and ~11 was confirmed for colloidal d > 30 nm. This degree of the reversibility was compared to previously reported SARS-CoV-2 Alpha spike protein coated gold colloids. It was concluded that Omicron spike protein possesses a similar low affinity for gold nano particle d < 20 nm and possesses the higher affinity to the gold nanoparticles of d > 30 nm. However, the Omicron spike protein conformation was presumed to be more denatured compared to the SARS-CoV-2 Alpha spike protein. Our finding suggested Omicron spike protein was more acid labile/flexible.

Keywords: Gold nano-particles; Omicron; Protein corona; Protein folding; Reversible aggregation; SARS-CoV-2; SPR (Surface plasmon resonance) band; Spike protein.