Fig. 5: Design and validation of SARS-CoV 2P DS S and MERS-CoV 2P DS S.

a, Sequence alignment showing the conservation of the residues involved in and adjacent to the designed disulfide bond across human coronavirus S glycoproteins. Residues are highlighted if they are identical in the alignment (black) or conservatively substituted (gray). Residues are numbered according to the SARS-CoV-2 S sequence. Green triangles highlight residues involved in the designed disulfide bond. b, SDS–PAGE analysis of MERS-CoV 2P S and MERS-CoV 2P DS S in reducing and nonreducing conditions showing formation of an intermolecular disulfide bond. c, 3D reconstruction in two orthogonal orientations of negatively stained MERS-CoV 2P DS S confirming proper folding of the designed protein construct. d, SDS–PAGE analysis of SARS-CoV 2P S and SARS-CoV 2P DS S in reducing and nonreducing conditions showing formation of an intermolecular disulfide bond. e, 3D reconstruction in two orthogonal orientations of negatively stained SARS-CoV 2P DS S confirming proper folding of the designed protein construct. f,g, Binding of various concentrations of the human neutralizing antibodies S309 (f) and S304 (g) to immobilized SARS-CoV 2P DS S (green) or SARS-CoV 2P S (black). Data are shown as mean and s.d. of n = 2 technical replicates; data are representative of two independent experiments.