Figure 6.

pH dependences of the net charge nz of unfolded (curves 1, 3) and 3D folded (curves 2, 4) polypeptide chain of RBD of the S-protein of the wild-type strain (curves 1, 2) and omicron variant (curves 3, 4) of the SARS-CoV-2 coronavirus. The amino acid sequences of the two polypeptide chains correspond to those of the recombinant proteins used in the isoelectric focusing experiment: His tag is attached to the C end of the polypeptide chains. The nz values are calculated with step 0.1 pH units; the isoelectric point pI is equal to pH at nz = 0.