Human coronavirus 229E nonstructural protein 13 (nsp13) exhibits NTPase, dNTPase, RNA 5'-triphosphatase, and both RNA and DNA duplex-unwinding activities in vitro.
The human coronavirus 229E (HCoV-229E) replicase gene-encoded nonstructural protein 13 (nsp13) contains an N-terminal zinc-binding domain and a C-terminal superfamily 1 helicase domain. A histidine-tagged form of nsp13, which was expressed in insect cells and purified, is reported to unwind efficiently both partial-duplex RNA and DNA of up to several hundred base pairs. Characterization of the nsp13-associated nucleoside triphosphatase (NTPase) activities revealed that all natural ribonucleotides and nucleotides are substrates of nsp13, with ATP, dATP, and GTP being hydrolyzed most efficiently. Using the NTPase active site, HCoV-229E nsp13 also mediates RNA 5'-triphosphatase activity, which may be involved in the capping of viral RNAs.
Ivanov et al. (Fri,) conducted a other in Human Coronavirus 229E. HCoV-229E nsp13 vs. HEL_KA (inactive control protein) was evaluated on Enzymatic activities (NTPase, dNTPase, RNA 5'-triphosphatase, and duplex-unwinding). Human coronavirus 229E nonstructural protein 13 (nsp13) exhibits NTPase, dNTPase, RNA 5'-triphosphatase, and both RNA and DNA duplex-unwinding activities in vitro.