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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' (beta, gamma 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' alpha phosphate could be removed from ssDNA, ssRNA, dsDNA and dsRNA thus confirming that rNSs has a novel 5' alpha 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.

Diaminopropionate (DAP) ammonia lyase (a PLP-dependent enzyme; EC 4.3.1.15) catalyzes the \alpha,\beta-elimination reaction of both L- and D-\alpha,\beta-diaminopropionate to form pyruvate and ammonia. Escherichia coli DAP ammonia lyase gene was cloned and overexpressed in E. coli and the protein was purified to homogeneity and crystallized using the hanging-drop vapour-diffusion technique. Crystals of two different morphologies were obtained, one of which belonged to the tetragonal space group $P4_12_12$ (or $P4_32_12$), with unit-cell parameters a = b = 86.01, c = 209.56 \AA, and the other to the monoclinic space group $P_21$, with unit-cell parameters a = 87.78, b = 94.35, c = 96.02 \AA, = 109.73°. The tetragonal crystals diffracted X-rays to 3.0 \AA resolution, while diffraction from the monoclinic form extended to 2.5 \AA. Complete X-ray diffraction data sets have been collected for both crystal forms.