AVM

Protein name	Hemagglutinin
Uniprot protein ID	C3W627
Protein length	566 amino acids
Protein description	The HA protein is translated as an uncleaved HA0 precursor protein, folded as a trimer, and glycosylated and acylated. The HA protein binds to sialic acid-containing receptors on the cell surface, bringing about the attachment of the virus particle to the cell. This attachment induces virion internalization either through clathrin-dependent endocytosis or through clathrin- and caveolin-independent pathway. Plays a major role in the determination of host range restriction and virulence. Class I viral fusion protein. Responsible for penetration of the virus into the cell cytoplasm by mediating the fusion of the membrane of the endocytosed virus particle with the endosomal membrane. Low pH in endosomes induces an irreversible conformational change in HA2, releasing the fusion hydrophobic peptide. Several trimers are required to form a competent fusion pore.

Pubmed ID	30799182
Clinical information	Yes
Disease	-
Published year	2019
Journal	J Infect Public Health
Title	Atypical influenza A(H1N1)pdm09 strains caused an influenza virus outbreak in Saudi Arabia during the 2009-2021 pandemic season
Author	Anis Khan,Mohammed A AlBalwi,Ibraheem AlAbdulkareem,Abdulrahman AlMasoud,Abdulrahman AlAsiri
Evidence	E374K (E47K in HA2 subunit) was found in 9/43 (20.9%) isolates randomly distributed in the phylogenetic tree. Two out of nine cases with E47K mutation appeared to have underlying asthma along with the cardiac and renal disease. A diversity of other substitutions detected spatially or in combination with others were C538A/F/R (residue 311 in HA2 subunit) in 6/43 (13.9%), N294S in 3/43 (6.9%), D222E, I266V, D35Y/N, and S84G/N in 2/43 (4.6%) isolates. There was a case with double mutation R319K/I321G, and another one with triple mutation N31D/D35N/S84N (Fig. 2A). Mutations observed in the NAgene of Saudi isolates with respect to the prototype A/California/07/2009 are presented in Table 4 and annotated in Fig. 2B. All of the Saudi isolates possessed V106I, N248D, and residue H275 (Table 4). The novel NA mutations detected in Saudi strains were E462D in 7/43 (16.2%), I365T in 5/43 (11.6%), and N369T in 2/43 (4.6%) isolates. We did not detect amino acid substitutions A247N, I223V or R [17], known to reduce the susceptibility to NAI in Saudi isolates.