Table 3.
Amino acid analysis of key sites in the internal gene.
| Protein | Sites | BJ/712/ | HB/28/ | BJ/142/ | BJ/293/ | HB/179/ | HB/182/ | YN/438/ | HK/Y280 | Eshkol/1436 | RSA/9508103 | Functiona |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PB2 | L89V | V | V | V | V | V | V | V | V | V | V | Increased virulence in mice21 |
| G309D | D | D | D | G | D | D | D | D | D | D | ||
| R477G | G | G | G | G | G | G | G | G | G | G | ||
| I495V | V | V | V | V | V | V | V | T | V | V | ||
| E627K | E | E | E | E | E | E | E | E | E | E | Increased virulence and transmissibility in mammals46,47 | |
| D701N | D | D | D | D | D | D | D | D | D | D | Increased virulence and transmissibility in mammals46,47 | |
| PB1 | L13P | P | P | P | P | P | P | P | P | P | uk | Mammalian host-specific markers43 |
| I368V | V | V | V | V | V | V | V | I | I | I | Airborne transmissibility in ferrets22 | |
| PA | N383D | D | D | D | D | D | D | D | D | D | D | Increased virulence in ducks23 |
| A515T | T | T | T | T | T | T | T | T | T | T | Increased virulence in ducks24 | |
| F672L | L | L | L | L | L | L | L | L | L | L | Airborne transmissibility in chickens44 | |
| M1 | V15I | I | I | I | I | I | I | I | I | I | V | Mammalian host-specific markers9 |
| N30D | D | D | D | D | D | D | D | D | D | D | Increased virulence in mice25 | |
| T215A | A | A | A | A | A | A | A | A | A | A | Increased virulence in mice25 | |
| M2 | S31N/G | N | N | N | N | N | N | N | S | S | S | Resistance to M2-blocker antiviral drugs48 |
| L55F | F | F | F | F | F | F | F | F | F | L | Mammalian host-specific markers9 | |
| NS1 | P42S | S | S | S | S | S | S | S | S | S | S | Increased virulence in mice28 |
| V149A | A | A | A | A | A | A | A | A | A | A | Increased virulence in mice29 |
aThe functions of each site were described in brief, and the related references were superscript.