Table. Alignment of residues involved receptor binding of hemagglutinin of influenza A viruses*.

Origin/subtype	Isolate name	Amino acid position (H3 numbering)
		131	135	137	138	152	186	190	193	200	222	224	225	226	227	228
Human/H3N2	A/Panama/2007/1999	A	T	S	A	N	S	D	S	G	W	R	G	V	S	S
Human/H3N2	A/Texas/50/2012	T	T	S	A	N	G	D	F	G	R	R	N	I	P	S
Human/H3N2	A/Brisbane/10/2007	T	T	S	A	N	V	N	F	G	R	R	N	I	P	S
Human/H1N1	A/California/04/2009	D	V	A	A	I	S	D	S	T	K	R	D	Q	E	G
Human/H1N1	A/Texas/36/1991	V	V	T	S	L	S	D	A	A	K	R	G	Q	E	G
Human/H1N1	A/Brisbane/59/2007	T	V	A	S	L	P	D	A	A	K	R	D	Q	E	G
Avian/H1N1	A/duck/Alberta/1976	T	V	A	A	L	P	E	S	A	E	R	G	Q	A	G
Avian/H7N1	A/rhea/North Carolina/39482/1993	R	A	S	A	K	G	E	K	T	F	S	G	R	I	D
Avian/H6N1	A/mallard/Sweden/81/2002	D	V	K	A	L	P	E	T	R	A	N	G	Q	R	G
Avian (human isolate)/H5N1	A/Vietnam/1203/2004	A	V	S	A	V	N	E	K	T	K	N	G	Q	S	G
Avian (human isolate)/H7N9	A/Anhui/1/2013	R	A	S	A	K	V	E	K	K	Q	N	G	L	S	G
Avian/H10N7	A/shorebird/Delaware Bay/10/2004	N	T	R	A	K	S	E	D	L	Q	N	G	Q	S	G
Avian/H10N7	A/mallard/Interior Alaska/10BM01929/2010	N	T	K	A	K	S	E	D	L	Q	N	G	Q	S	G
Avian (seal isolate)/H10N7	A/harbor seal/Germany/1/2014	N	T	K	A	K	S	E	D	L	Q	N	G	Q	S	G
Avian (human isolate)/H10N8	A/Jiangxi-Donghu/346–1/2013	N	T	R	A	K	S	E	D	L	Q	N	G	Q	S	G

*Residues found in human H1 or H3 and in H10 hemagglutinin but not in other avian hemagglutinin sequences are shown in bold.