The 3C-like serine proteinase is responsible for the majority of cleavages. The helicase which contains a zinc finger structure displays RNA and DNA duplex-unwinding activities with 5' to 3' polarity. The exoribonuclease acts on both ssRNA and dsRNA in a 3' to 5' direction. NendoU is a Mn(2+)-dependent, uridylate-specific enzyme, which leaves 2'-3'-cyclic phosphates 5' to the cleaved bond. a ribonucleoside 5'-triphosphate + RNA(n) = diphosphate + RNA(n+1) ATP + H2O = ADP + H(+) + phosphate ATP + H2O = ADP + H(+) + phosphate The hydrophobic domains (HD) could mediate the membrane association of the replication complex and thereby alter the architecture of the host cell membrane. Specific enzymatic cleavages in vivo by its own protease yield mature proteins. 3CL-PRO is autocatalytically processed (By similarity). Produced by -1 ribosomal frameshifting at the 1a-1b genes boundary.