TABLE 2.

Amino acid variations along the major trunk of the phylogenetic trees of A/H1N1pdm virus HA and NA glycoproteins over time.

Gene	Amino acid position	2010	2011	2012	2013	2014	2015	2016	2017	2018	Structural mapping (solvent exposure and antigenic epitope location)
HA	391	E391K
	202		S202T								Sb antigenic sites
	468		S468N
	114			D114N
	180				K180Q						Sa antigenic sites
	273				A273T
	300				K300E
	516				E516K
	101							S101N
	179							S179N			Sa antigenic sites
	233							I233T
	181								S181T		Sa antigenic sites
	91									S91R	Cb antigenic sites
	200									S200P	Antigenic epitope (190-helix), adjacent to RBS
	312									I312V
NA	241		V241I
	369		N369K								Antigenic sites
	44				N44S
	106				I106V
	200				N200S
	34					I34V
	321					I312V
	386					N386K
	432					K432E
	13						V13I
	314						I314M				Antigenic sites
	188							I188T
	77								G77R/K
	81								V81A
	449								N449D