FIG 7.

Putative MBX2329 and MBX2546 binding region in HA. HA is a trimer consisting of three identical copies of the HA protein (the three monomers are shown in blue). Each monomer contains two subunits, HA1 and HA2. HA1 is the receptor binding domain (RBD) and contains the sialic acid binding pocket. HA2 contains the membrane fusion machinery. MAb C179 blocks membrane fusion. MAb C179 binds the HA stem and interacts with residues from the N- and C-terminal regions of HA1 (residues 38, 40, 42, 291 to 293, and 318) and the N-terminal portion of HA2 (residues 18 to 21, 38, 41 to 43, 45, 46, 52, and 56), including helix A. The putative binding sites of MBX2329 and MBX2546 overlap this region.