Table 2.
Properties of the 2A proteins and peptides of picornaviruses
| Virus | Size (residues)‡ | Isoelectric point§ | Identifiable domains/motifs | Number of species | Interspecies sequence conservation|| | |
|---|---|---|---|---|---|---|
| Genus | Species* | |||||
| Cosavirus | All 5 species | 30–37 | ND | NPG(P) | 5 | ND |
| Senecavirus | SVV | 9 | ND | NPG(P) | 1 | NA |
| Teschovirus | PTV | 21 | ND | NPG(P) | 1 | NA |
| Erbovirus | ERBV | 16 | ND | NPG(P) | 1 | NA |
| Aphthovirus | FMDV | 18 | ND | NPG(P) | 3 | ND |
| ERAV | 18 | ND | ||||
| BRV | 19 | ND | ||||
| Cardiovirus | EMCV | 143 | 9.67 | NPG(P) | 2 | 24% (42%) |
| TMEV | 133 | 8.89 | ||||
| Sapelovirus | ASV | 12 | ND | None | 3 | ND for all 3 species; 27% (39%) for SSV and PSV |
| SSV | 292–302 | 5.00 | Protease¶ | |||
| PSV | 226 | 5,55 | Protease¶ | |||
| Kobuvirus | AiV | 111 | 5.92 | H-NC¶ | 3 | 54% (66%) |
| BKV | 134 | 5.51 | ||||
| PKV | 136 | 5.38 | ||||
| Parechovirus | LV 2A1 | 20 | ND | NPG(P) | 2 | 44% (64%) for 2A2 of LV and 2A of HPeV |
| LV 2A2 | 135 | 6.60 | H-NC | |||
| HPeV | 160 | 5.28 | H-NC | |||
| Avihepatovirus | DHV 2A1 | 20 | ND | NPG(P) | 1 | NA |
| DHV 2A2+2A3 | 285 | 8.65 | AIG1 and H-NC | |||
| Hepatovirus | HAV | 189 | 8.78 | None | 1 | NA |
| Tremovirus | AEV | 163 | 8.22 | H-NC | 1 | NA |
| Enterovirus | All 10 species | 142–150 | 5.22–6.30 | Pico_P2A | 10 | 35% (51%) |
| Klassevirus | HKV | 126 | 4.80 | None | 1 | NA |
| Unclassified | SePV-1 2A1 | 29 | ND | NPG(P)# | 1 | NA |
| SePV-1 2A2 | 100 | 7.92 | None | 1 | NA | |
| AEV, avian encephalomyelitis virus; AiV, Aichi virus; ASV, avian sapelovirus; BKV, bovine kobuvirus; BRV, bovine rhinitis B virus; DHV, duck hepatitis A virus; EMCV, encephalomyocarditis virus; ERAV, equine rhinitis A virus; ERBV, equine rhinitis B virus; FMDV, foot-and-mouth disease virus; HAV, hepatitis A virus; HKV, human klassevirus; HPeV, human parechovirus; LV, Ljungan virus; NA, not applicable; ND, not determined; PKV, porcine kobuvirus; PSV, porcine sapelovirus; PTV, porcine teschovirus; SePV-1, seal picornavirus type 1; SSV, simian sapelovirus; SVV, Seneca Valley virus; TMEV, Theiler's murine encephalomyelitis virus. | ||||||
| *For those viruses with more than one 2A protein, the specific protein analysed is indicated. | ||||||
| ‡According to the data in GenBank. | ||||||
| §Values were calculated only for peptides with >40 residues using ProtParam132. | ||||||
| ||For the viral genera with more than one species, the level of interspecies amino acid identity (and similarity, in parentheses) was calculated with the aid of CLUSTAL_X2 alignments, using utilities implemented in BioEdit and the BLOSUM62 similarity matrix134. To focus on the core protein sequences, the internal insertions of >15 amino acid residues, as well as terminal insertions, were not taken into account. | ||||||
| ¶These are manually recognizable motifs. | ||||||
| #One of the strains is reported to harbour an NPR(P) motif instead of NPG(P). | ||||||