NSs encoded by groundnut bud necrosis virus is a bifunctional enzyme

Lokesh, Bhushan ; Rashmi, Panigrahi R. ; Amruta, Bhat S. ; Srisathiyanarayanan, Dharmaiah ; Murthy, Mathur R. N. ; Savithri, Handanahal S. (2010) NSs encoded by groundnut bud necrosis virus is a bifunctional enzyme PLoS One, 5 (3). e9757_1-e9757_10. ISSN 1932-6203

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Official URL: http://www.plosone.org/article/info%3Adoi%2F10.137...

Related URL: http://dx.doi.org/10.1371/journal.pone.0009757

Abstract

Groundnut bud necrosis virus (GBNV), a member of genus Tospovirus in the family Bunyaviridae, infects a large number of leguminosae and solanaceae plants in India. With a view to elucidate the function of nonstructural protein, NSs encoded by the small RNA genome (S RNA), the NSs protein of GBNV- tomato (Karnataka) [1] was over-expressed in E. coli and purified by Ni-NTA chromatography. The purified rNSs protein exhibited an RNA stimulated NTPase activity. Further, this activity was metal ion dependent and was inhibited by adenosine 5' (β, γ imido) triphosphate, an ATP analog. The rNSs could also hydrolyze dATP. Interestingly, in addition to the NTPase and dATPase activities, the rNSs exhibited ATP independent 5' RNA/DNA phosphatase activity that was completely inhibited by AMP. The 5' α phosphate could be removed from ssDNA, ssRNA, dsDNA and dsRNA thus confirming that rNSs has a novel 5' α phosphatase activity. K189A mutation in the Walker motif A (GxxxxGKT) resulted in complete loss of ATPase activity, but the 5' phosphatase activity was unaffected. On the other hand, D159A mutation in the Walker motif B (DExx) resulted in partial loss of both the activities. These results demonstrate for the first time that NSs is a bifunctional enzyme, which could participate in viral movement, replication or in suppression of the host defense mechanism.

Item Type:Article
Source:Copyright of this article belongs to Public Library of Science.
ID Code:45976
Deposited On:29 Jun 2011 10:07
Last Modified:18 May 2016 02:03

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