Table 1.

Deduced amino acid sequences of engineered HACS motifs of reverse genetics viruses.

Reverse genetics virus	HACS motif a
	HA1												HA2
	P12	P11	P10	P9	P8	P7	P6	P5	P4	P3	P2	P1	P1’
rgHPAIV	N	S	P	Q	R	E	R	R	R	K	K	R	G
rgLPAIV	N	S	P	Q	R	E	—	—	—	—	T	R	G
Mutant 5	N	S	P	Q	R	E	—	—	—	—	K	R	G
Mutant 6	N	S	P	Q	R	—	—	—	—	K	T	R	G
Mutant 7	N	S	P	Q	—	—	—	—	R	K	K	R	G
Mutant 4	N	S	P	Q	R	E	—	—	R	K	K	R	G
Mutant 8	N	S	P	Q	—	—	—	R	R	K	K	R	G
Mutant 9	N	S	P	Q	R	E	—	R	R	K	K	R	G
Mutant 2	N	S	P	Q	R	E	R	R	R	K	T	R	G
Mutant 1	N	S	P	Q	R	E	R	R	Q	K	K	R	G
Mutant 3	N	V	P	Q	R	E	R	R	R	K	K	R	G

¹Dash indicates deletion, underlined indicates mutation. Cleavage occurs C-terminally at the scissile bond between P1 (HA₁) and P1’ (HA₂). The HACS motif is flanked N-terminally by PQ, and C-terminally by G.