Figure 2.

Cryo-EM structure of S-ECD (Omicron) in complex with STS165

(A) The domain-colored cryo-EM structure of S-ECD (Omicron) in complex with STS165 is shown in two perpendicular views. STS165 binds to three “up” RBDs, which the heavy and light chains of it are colored blue and cyan, respectively. Each of the Spike trimer is colored pink, orange, and gray, respectively.

(B) Structural comparison between ACE2 (green) and STS165 bound to RBD, and the spatial overlap of them is represented by a black x.

(C) Structural classification of some Class 4 representative nAbs, which are similar to the STS165 epitope. H014 (PDB: 7CAH), EY6A (PDB: 6ZFO), and S304 (PDB: 7R6X).

(D) The binding epitope of STS165 bound to the RBD is colored blue on the left, which overlaps with the mutated residues (purple) relative to the RBD (Wuhan-Hu-1) on S373 and S375.

(E) The binding interface between STS165 and RBD (Omicron). The mutated residues relative to the RBD (Wuhan-Hu-1) are shown as purple spheres.

(F) The representative bivalent binding 2D classification of Omicron S-6p bound to STS165.

(G) The proposed inter-Spike bivalent binding model of STS165 based on the structures.