AVM

Protein name	Neuraminidase
Uniprot protein ID	C3W6G3
Protein length	469 amino acids
Protein description	The NA assembles as a tetramer of four identical polypeptides and, when embedded in the envelope of the virus, accounts for approximately 10-20% of the total glycoproteins on the virion surface, with about 40-50 NA spikes and 300-400 HA spikes on an average sized virion of 120 nm. The four monomers, each of approximately 470 amino acids, fold into four distinct structural domains: the cytoplasmic tail, the transmembrane region, the stalk, and the catalytic head. The NA catalyzes the removal of terminal sialic acid residues from viral and cellular glycoconjugates. Cleaves off the terminal sialic acids on the glycosylated HA during virus budding to facilitate virus release. Additionally helps virus spread through the circulation by further removing sialic acids from the cell surface. These cleavages prevent self-aggregation and ensure the efficient spread of the progeny virus from cell to cell. Otherwise, infection would be limited to one round of replication. Described as a receptor-destroying enzyme because it cleaves a terminal sialic acid from the cellular receptors. May facilitate viral invasion of the upper airways by cleaving the sialic acid moities on the mucin of the airway epithelial cells.

Pubmed ID	30066273
Clinical information	No
Disease	-
Published year	2018
Journal	Arch Virol
Title	Evolution and dynamics of the pandemic H1N1 influenza hemagglutinin protein from 2009 to 2039
Author	Hebah A Al Khatib,Asmaa A Al Thani,Hadi M Yassine
Evidence	Mutations were either gradually accumulated to become fixed in currently circulating strains (D114N, S179N, S202T, S220T, I233T, K300E and E391K) or dynamic in terms of appearance and disappearance, both spatially and temporally (A203T, N458K and E508G). Some of the reported mutations have been shown to increase infection severity (D239G/N; globular head), enhance HA binding affinity to its receptor (S200P and S202T; RBD), or have deleterious effect on HA function (N458K and E508G; stem region). The continuous accumulation of mutations at the Sa site led to the gradual acquisition of glycosylation at residue 179 starting from 2015, which became a dominant feature in all strains isolated in the following years. In addition to sharing common amino acid substitutions (e.g. S179N in HA head and E537K in HA stem)