Table 1.

Amino acid mutations involved in mammalian infection with H5N1 virus.

Viral components	Protein	Mutation	Adaptive Mechanism in Mammalian System	Reference
Surface glycosylation protein	HA	N154S	Increase α2, 6 binding of H5N1 subtype	[28]
		A158T	Decrease α2, 3 binding by oligosaccharide modification of H5N1 subtype	[33]
		N182K	Increase α2, 6 binding and decrease α2, 3 binding of H5N1 subtype	[29]
		Q192R	Increase α2, 6 binding and decrease α2, 3 binding of H5N1 subtype	[29]
		Q222L	Increase α2, 6 binding and decrease α2, 3 binding of H5N1 subtype	[28]
		S223N	Increase α2, 6 binding and decrease α2, 3 binding of H5N1 subtype	[28]
		G224S	Increase α2, 6 binding and decrease α2, 3 binding of H5N1 subtype	[28]
		Q226L	Increase α2, 6 binding and decrease α2, 3 binding of H2,H3,H5,H9 subtype	[21,24,26,27]
		S227N	Increase α2, 6 binding and decrease α2, 3 binding of H5N1 subtype	[30]
		G228S	Increase α2, 6 binding of H5N1 subtype	[31]
	NA	Deletion in stalk	Functional balance with HA by decreasing enzyme activity of H5N1 subtype	[33,79]
Polymerase	PB1	L473V	Increase polymerase activity of H5N1 and 2009pH1N1 subtype	[56]
		L598P	Increase polymerase activity of H5N1 subtype	[56]
	PB2	Q591K	Increase polymerase activity of H5N1 and 2009 pH1N1 subtype	[54]
		E627K	Increase polymerase activity of H5N1 subtype	[51,52]
		D701N	Increase polymerase activity by binding to beneficial importin α isoform in H5N1 and H7N7 subtype	[47]
Non-structural protein	NS1	PDZ domain in C-terminus	Bind to host PDZ-carrying proteins to interfere host signal pathway	[69,70,71,72]
		S103F, I106M	Bind to host CPSF30 to inhibit protein synthesis	[65,66]
Nuclear export protein	NEP	M16I	Increase polymerase activity of H5N1 subtype	[57]