title: Human coronavirus 229E nonstructural protein 13: characterization of duplex-unwinding, nucleoside triphosphatase, and RNA 5'-triphosphatase activities.
abstract: 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.
authors.affiliation: Institute of Virology and Immunology, University of Würzburg, Würzburg, Germany.
authors.forename: Konstantin A
authors.initials: KA
authors.lastname: Ivanov
authors.forename: John
authors.initials: J
authors.lastname: Ziebuhr
mesh_terms: D017766:Acid Anhydride Hydrolases / Q000378:metabolism*; D028941:Coronavirus 229E, Human / Q000201:enzymology* / Q000235:genetics; D004265:DNA Helicases / Q000378:metabolism*; D006801:Humans; D043583:Nucleoside-Triphosphatase / Q000378:metabolism*; D020365:RNA Helicases / Q000378:metabolism*; D013379:Substrate Specificity; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D017361:Viral Nonstructural Proteins; D017766:Acid Anhydride Hydrolases; C023090:RNA triphosphatase; D043583:Nucleoside-Triphosphatase; D004265:DNA Helicases; D020365:RNA Helicases