Table 1.

Spatial distance between epitopes of HA and the receptor-binding site

Epitope	Spatial distance, Å
A	10.7
B	13.0
C	44.5
D	17.7
E	25.5
O	35.8

Shown are the distances between the centroid of atomic positions of amino acids found in each epitope and the centroid of atomic positions of amino acids found in the receptor-binding site. The distances are based on chain A of the HA 3D structure (PDB ID: 1hgf) of A/Aichi/2/68 (A/H3N2). A, B, C, D, E, and O are defined in the legend of Fig. 4.