Fig. 5: Structural basis for breadth of AR4A recognition.

a Surface representation of sE1E2.SZ bound by AR4A variable region (cartoon). Molecules are colored as in Fig. 1, with the bridging domain colored red and the AR4A epitope on E2 colored wheat. N-linked glycans are shown as cyan spheres. b Closeup view of AR4A epitope on E2, rotated by 90° relative to (a). AR4A HCDR3 and HCDR2 residues that interact with E2 are shown as sticks and colored purple and magenta, respectively. c AR4A heavy chain (HC) and light chain (LC) paratope buried surface areas (BSA), parsed by CDR. d Sequence alignment of AR4A heavy and light chains against their respective germline precursors. Residues that interact with E2 are labeled with asterisks and underlined, and somatically matured residues are shaded cyan. e Weighted mean scaled Shannon sequence entropy and mean percent sequence conservation of structurally characterized antibody epitopes that target E2 (antigenic domains, AD; antigenic regions, AR). f Closeup view of AR4A epitope on E2, rotated by 90° relative to (a), with the E2 surface colored by residue sequence entropy on a scale from 0 (conserved, white) to 100 (variable, purple). AR4A residues are depicted as in (b). Raw sequence entropies were calculated in units of nats. Source data are provided as a Source Data file.