Viruses with Single-Stranded, Positive-Sense RNA Genomes

Table 14.3 Comparison of the properties of picornavirus proteins

Protein	Number of amino acid residues					Modification	Function
Protein	Poliovirus	Coxsackievirus	Hepatitis A virus	Rhinovirus	Foot-and-mouth disease virus	Modification	Function
Leader					205		Protease, performs the autocatalytic cleavage of the protomer, induces the degradation of eIF-4G
VP4	69	69	23	69	81	Myristoylated (lacking in hepatitis A virus)	Structural protein, on the inner side of the particle, interacts with RNA
VP2	271	261	222	262	218		Structural protein
VP3	238	238	246	236	221		Structural protein
VP1	302	284	274	290	212		Structural protein
2A	149	147	71	145	16		Enteroviruses, rhinoviruses: protease, performs protomer cleavage before of the 2A domain of polyprotein
							Aphthoviruses, erboviruses, cardioviruses: protease, performs protomer cleavage after the 2A domain of polyprotein, mediates the degradation of eIF-4G
							Hepatoviruses, parechoviruses: no protease, active during morphogenesis
2B	97	99	215	97	154		Influences host specificity
2C	329	329	335	330	317	NTP-binding	ATPase, initiation of RNA synthesis, chaperone activity forming ribonucleoprotein complexes?, helicase activity?
3A	87	89	74	85	154		Hydrophobic domain for anchoring the 3AB precursor on the membrane, influences uridylylation of Vpg
3B	22	22	23	23	23/24	Uridylylated	Vpg, covalently linked to the 5′ terminus of the viral genome
3C	182	183	219	182	214		Protease, performs all cleavage reactions, except for VP0 to VP4 and VP2 and for the protomer
3D	461	462	489	460	470		RNA-dependent RNA polymerase

The protein succession order in the table corresponds to the real sequence order in the polyprotein
NTP nucleoside triphosphate