Hemagglutinin-neuraminidase explained

Symbol:	HN
Hemagglutinin-neuraminidase, Paramyxoviridae
Pfam:	PF00423
Pfam Clan:	CL0434
Interpro:	IPR000665
Scop:	1usr
Cazy:	GH83
Cdd:	cd15469
Pdb:	,,,,,,,,,

Hemagglutinin-neuraminidase refers to a single viral protein that has both hemagglutinin and (endo) neuraminidase activity. This is in contrast to the proteins found in influenza, where both functions exist but in two separate proteins. Its neuraminidase domain has the CAZy designation glycoside hydrolase family 83 (GH83).^[1]

It does show a structural similarity to influenza viral neuraminidase and has a six-bladed beta-propeller structure.^[2] This Pfam entry also matches measles hemagglutinin (cd15467), which has a "dead" neuraminidase part repurposed as a receptor binding site.^[3]

Hemagglutinin-neuraminidase allows the virus to stick to a potential host cell, and cut itself loose if necessary. Hemagglutinin-neuraminidase can be found in a variety of paramyxoviruses including mumps virus, human parainfluenza virus 3, and the avian pathogen Newcastle disease virus.

Types include:

• Mumps hemagglutinin-neuraminidase
• Parainfluenza hemagglutinin-neuraminidase

Hemagglutinin-neuraminidase inhibitors have been investigated and suggest that there may applications for human use in the future.^[4]

Notes and References

1. Yuan P, Thompson TB, Wurzburg BA, Paterson RG, Lamb RA, Jardetzky TS . Structural studies of the parainfluenza virus 5 hemagglutinin-neuraminidase tetramer in complex with its receptor, sialyllactose. . Structure . 2005 . 13 . 5 . 803–15 . 15893670 . 10.1016/j.str.2005.02.019 . free .
2. Lawrence MC, Borg NA, Streltsov VA, etal . Structure of the haemagglutinin-neuraminidase from human parainfluenza virus type III . J. Mol. Biol. . 335 . 5 . 1343–57 . January 2004 . 14729348 . 10.1016/j.jmb.2003.11.032.
3. Colf . LA . Juo . ZS . Garcia . KC . Structure of the measles virus hemagglutinin. . Nature Structural & Molecular Biology . December 2007 . 14 . 12 . 1227–8 . 10.1038/nsmb1342 . 18026116. 40292 .
4. Alymova IV, Taylor G, Takimoto T, etal . Efficacy of novel hemagglutinin-neuraminidase inhibitors BCX 2798 and BCX 2855 against human parainfluenza viruses in vitro and in vivo . Antimicrob. Agents Chemother. . 48 . 5 . 1495–502 . May 2004 . 15105096 . 400544 . 10.1128/AAC.48.5.1495-1502.2004.