Overall structures of Sb14, Sb16, Sb45, and Sb68 complexed with the SARS-CoV-2 RBD.Ribbon (sybodies) and ribbon plus surface (RBD) representations of the complex of (A) Sb16 (slate) with the RBD (gray) (7KGK); (B) Sb45 (cyan) with the RBD (7KGJ); (D) Sb45 and Sb68 (purple) with the RBD (7KLW), and (E) Sb14 (blue) and Sb68 (magenta) with the RBD (7MFU). Sb16–RBD and Sb45–RBD superimposed based on the RBD are shown in panel C, to highlight CDR loops, which are color-coded as CDR1 (pink), CDR2 (orange), and CDR3 (red). The CDR2 of Sb16 and CDR3 of Sb45 interact similarly with the RBD surface. Panel F shows a sequence alignment of the four sybodies. CDR1, complementarity-determining region 1; CDR2, complementarity-determining region 2; CDR3, complementarity-determining region 3; RBD, receptor-binding domain; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.