Methyltransferase: Displays a capping enzyme activity. This function is necessary since all viral RNAs are synthesized in the cytoplasm, and host capping enzymes are restricted to the nucleus. The enzymatic reaction involves a covalent link between 7-methyl-GMP and the methyltransferase, whereas eukaryotic capping enzymes form a covalent complex only with GMP. Methyltransferase catalyzes transfer of a methyl group from S-adenosylmethionine to GTP and GDP to yield m(7)GTP or m(7)GDP. This enzyme also displays guanylyltransferase activity to form a covalent complex, methyltransferase-m(7)GMP, from which 7-methyl-GMP is transferred to the mRNA to create the cap structure. Papain-like cysteine protease: May participate in the processing of polyprotein pORF1 together with cellular proteases and the cleavage of capsid protein ORF2. NTPase/helicase: Multi-functional protein that exhibits NTPase and RNA unwinding activities. Hydrolyzes all NTPs efficiently and unwinds RNA duplexes containing 5' overhangs. Possesses a sequence independent RNA-5'-triphosphatase (RTPase) activity suggestive of its role in forming viral cap structure (PubMed:20071563) (By similarity). Participates also in viral genome replication, RNA translocation and genome packaging/unpackaging (By similarity). RNA-directed RNA polymerase: Plays an essential role in the virus replication. Binds to the 3'-end of the genomic RNA to initiate viral replication. a ribonucleoside 5'-triphosphate + RNA(n) = diphosphate + RNA(n+1) It is not yet clear whether the ORF1-encoded polyprotein contains multiple biochemical activities, or undergoes cis or trans- processing to release biochemically distinct peptides. No processing has been observed in mammalian expression systems. However, the baculovirus expressed polyprotein is processed into smaller protein, probably by a cysteine protease. Belongs to the hepevirus non-structural polyprotein family.