1. The large protein ‘L’ of Peste-des-petits-ruminants virus exhibits RNA triphosphatase activity, the first enzyme in mRNA capping pathway
- Author
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Deepa Rajagopalan, Piyush Kumar Singh, Melkote S. Shaila, Asutosh Bellur, Mohammad Yunus Ansari, and Purnima Shanmugam
- Subjects
RNA Caps ,Guanylyltransferase ,Conventional mRNA capping ,Polyadenylation ,Genetic Vectors ,Gene Expression ,Biochemistry ,Article ,Virus ,Peste-des-petits-ruminants virus ,Viral Proteins ,03 medical and health sciences ,Virology ,Chlorocebus aethiops ,Peste-des-Petits-Ruminants ,Genetics ,RNA triphosphatase ,Animals ,RNA, Messenger ,Cloning, Molecular ,Vero Cells ,Molecular Biology ,030304 developmental biology ,Microbiology & Cell Biology ,0303 health sciences ,Messenger RNA ,biology ,030306 microbiology ,RNA virus ,General Medicine ,biology.organism_classification ,Molecular biology ,mRNA capping ,Acid Anhydride Hydrolases ,Enzyme Activation ,Protein L ,Morbillivirus ,Vesicular stomatitis virus ,biology.protein ,PPRV ,Peste-des-petits-ruminants virus L protein ,Baculoviridae - Abstract
Peste-des-petits-ruminants is a highly contagious and fatal disease of goats and sheep caused by non-segmented, negative strand RNA virus belonging to the Morbillivirus genus-Peste-des-petits-ruminants virus (PPRV) which is evolutionarily closely related to Rinderpest virus (RPV). The large protein 'L' of the members of this genus is a multifunctional catalytic protein, which transcribes and replicates the viral genomic RNA as well as possesses mRNA capping, methylation and polyadenylation activities; however, the detailed mechanism of mRNA capping by PPRV L protein has not been studied. We have found earlier that the L protein of RPV has RNA triphosphatase (RTPase), guanylyltransferase (GTase) and methyltransferase activities, and unlike vesicular stomatitis virus (VSV), follows the conventional pathway of mRNA capping. In the present work, using a 5'-end labelled viral RNA as substrate, we demonstrate that PPRV L protein has RTPase activity when present in the ribonucleoprotein complex of purified virus as well as recombinant L-P complex expressed in insect cells. Further, a minimal domain in the C-terminal region (aa1640-1840) of the L protein has been expressed in E. coli and shown to exhibit RTPase activity. The RTPase activity of PPRV L protein is metal-dependent and functions with a divalent cation, either magnesium or manganese. In addition, RTPase associated nucleotide triphosphatase activity (NTPase) of PPRV L protein is also demonstrated. This work provides the first detailed study of RTPase activity and identifies the RTPase domain of PPRV L protein.
- Published
- 2018