4HG4: Crystal structure of Fab 2G1 in complex with a H2N2 influenza virus hemagglutinin

Influenza virus hemagglutinin (HA) mediates receptor binding and viral entry during influenza infection. The development of receptor analogs as viral-entry blockers has not been successful, which suggests that sialic acid may not be an ideal scaffold to obtain broad, potent HA inhibitors. Here, we report crystal structures of Fab fragments from three human antibodies that neutralize the 1957 pandemic H2N2 influenza virus in complex with H2 HA. All three antibodies use an aromatic residue to plug a conserved cavity in the HA receptor-binding site. Each antibody interacts with the absolutely conserved HA1 Trp153 at the cavity base through pi-pi stacking with the signature Phe54 of two VH1-69-encoded antibodies or a tyrosine from HCDR3 in the other antibody. This highly conserved interaction can be used as a starting point to design inhibitors targeting this conserved hydrophobic pocket in influenza viruses.
PDB ID: 4HG4Download
MMDB ID: 107622
PDB Deposition Date: 2012/10/6
Updated in MMDB: 2017/11
Experimental Method:
x-ray diffraction
Resolution: 3.2  Å
Source Organism:
Influenza A virus (A/Japan/305+/1957(H2N2))
Similar Structures:
Biological Unit for 4HG4: dodecameric; determined by author
Molecular Components in 4HG4
Label Count Molecule
Proteins (12 molecules)
Hemagglutinin HA1
Molecule annotation
Hemagglutinin HA2
Molecule annotation
FAB 2G1 Heavy Chain
Molecule annotation
FAB 2G1 Light Chain
Molecule annotation
Chemicals (6 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB