title: Characterization of the reovirus lambda1 protein RNA 5'-triphosphatase activity.
abstract: Characterization of the phosphohydrolytic activities of recombinant reovirus lambda1 protein demonstrates that, in addition to the previously reported nucleoside triphosphate phosphohydrolase and helicase activities, the protein also possesses RNA 5'-triphosphatase activity. This activity was absolutely dependent on the presence of a divalent cation, Mg2+ or Mn2+, and specifically removes the 5'-gamma-phosphate at the end of triphosphate-terminated RNAs. Kinetic competition analysis showed that nucleoside triphosphate phosphohydrolase and RNA 5'-triphosphatase reactions are carried out at a common active site. These results strongly support the idea that, in addition to its role as an RNA helicase during transcription of the viral genome, lambda1 also participates during formation of the cap structure at the 5' end of newly synthesized reovirus mRNAs. The lambda1 protein represents only the third RNA triphosphatase whose primary structure is known and the first described in a double-stranded RNA virus.
authors.affiliation: Département de Microbiologie et Immunologie, Université de Montréal, Montréal, Québec H3C 3J7, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Bisaillon
authors.forename: G
authors.initials: G
authors.lastname: Lemay
mesh_terms: D017766:Acid Anhydride Hydrolases / Q000378:metabolism*; D001667:Binding, Competitive; D002213:Capsid / Q000378:metabolism*; D036022:Capsid Proteins; D004268:DNA-Binding Proteins; D020558:GTP Phosphohydrolases / Q000378:metabolism; D007700:Kinetics; D008274:Magnesium / Q000378:metabolism; D008345:Manganese / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D036022:Capsid Proteins; D004268:DNA-Binding Proteins; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; C090196:lambda 1 protein, reovirus; D008345:Manganese; D017766:Acid Anhydride Hydrolases; D020558:GTP Phosphohydrolases; C023090:RNA triphosphatase; D008274:Magnesium