A carboxy terminal domain of the L protein of rinderpest virus possesses RNA triphosphatase activity - The first enzyme in the viral mRNA capping pathway

Singh, Piyush Kumar and Ratnam, Nivedita and Narayanarao, Kannan Boosi and Bugatha, Harigopalarao and Karande, Anjali A and Subbarao, Shaila Melkote (2015) A carboxy terminal domain of the L protein of rinderpest virus possesses RNA triphosphatase activity - The first enzyme in the viral mRNA capping pathway. In: BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 464 (2). pp. 629-634.

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Abstract

The large protein L of negative-sense RNA viruses is a multifunctional protein involved in transcription and replication of genomic RNA. It also possesses enzymatic activities involved in capping and methylation of viral mRNAs. The pathway for mRNA capping followed by the L protein of the viruses in the Morbillivirus genus has not been established, although it has been speculated that these viruses may follow the unconventional capping pathway as has been shown for some viruses of Rhabdoviridae family. We had earlier shown that the large protein L of Rinderpest virus expressed as recombinant L-P complex in insect cells as well as the ribonucleoprotein complex from purified virus possesses RNA triphosphatase (RTPase) and guanylyltransferase activities, in addition to RNA dependent RNA polymerase activity. In the present work, we demonstrate that RTPase as well as nucleoside triphosphatase (NTPase) activities are exhibited by a subdomain of the L protein in the C terminal region (a.a. 1640 1840). The RTPase activity depends absolutely on a divalent cation, either magnesium or manganese. Both the RTPase and NTPase activities of the protein show dual metal specificity. Two mutant proteins having alanine mutations in the glutamic acid residues in motif-A of the RTPase domain did not show RTPase activity, while exhibiting reduced NTPase activity suggesting overlapping active sites for the two enzymatic functions. The RTPase and NTPase activities of the L subdomain resemble those of the Vaccinia capping enzyme D1 and the baculovirus LEF4 proteins. (C) 2015 Elsevier Inc. All rights reserved.

Item Type:	Journal Article
Publication:	BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
Publisher:	ACADEMIC PRESS INC ELSEVIER SCIENCE
Additional Information:	Copy right for this article belongs to the ACADEMIC PRESS INC ELSEVIER SCIENCE, 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA
Keywords:	Negative strand RNA viruses; RNA modification; mRNA capping; Metalloenzyme; Rinderpest virus L protein; RNA triphosphatase
Department/Centre:	Division of Biological Sciences > Biochemistry Division of Biological Sciences > Microbiology & Cell Biology
Date Deposited:	11 Sep 2015 04:35
Last Modified:	11 Sep 2015 04:35
URI:	http://eprints.iisc.ac.in/id/eprint/52317

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