Electrostatic Interaction\nbetween SARS-CoV‑2\nand Charged Surfaces: Spike Protein Evolution Changed the Game

Previous works show the key role of electrostatics in\nthe SARS-CoV-2\nvirus in aspects such as virus–cell interactions or virus inactivation\nby ionic surfactants. Electrostatic interactions depend strongly on\nthe variant since the charge of the Spike protein (responsible for\nvirus–environment interactions) evolved across the variants\nfrom the highly negative Wild Type (WT) to the highly positive Omicron\nvariant. The distribution of the charge also evolved from diffuse\nto highly localized. These facts suggest that SARS-CoV-2 should interact\nstrongly with charged surfaces in a way that changed during the virus\nevolution. This question is studied here by computing the electrostatic\ninteraction between WT, Delta and Omicron Spike proteins with charged\nsurfaces using a new method (based on Debye–Hückel theory)\nthat provides efficiently general results as a function of the surface\ncharge density σ. We found that the interaction of the WT and\nDelta variant spikes with charged surfaces is dominated by repulsive\nimage forces proportional to σ<sup>2</sup> originating at the\nprotein/water interface. On the contrary, the Omicron variant shows\na distinct behavior, being strongly attracted to negatively charged\nsurfaces and repelled from positively charged ones. Therefore, the\nSARS-CoV-2 virus has evolved from being repelled by charged surfaces\nto being efficiently adsorbing to negatively charged ones.