Stacking interactions of W271 and H275 of SeMV serine protease with W43 of natively unfolded VPg confer catalytic activity to protease

Nair, Smita and Gayathri, P and Murthy, MRN and Savithri, HS (2008) Stacking interactions of W271 and H275 of SeMV serine protease with W43 of natively unfolded VPg confer catalytic activity to protease. In: Virology, 382 (1). pp. 83-90.

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Abstract

N-terminal serine protease domain of Sesbania mosaic virus polyprotein, requires fused VPg for its activity. W43 of VPg mediates aromatic stacking interactions (characterized by 230 nm positive CD peak) with protease. A stretch of aromatic residues (F269, W271, Y315, and Y319) exposed in the protease domain were mutated to identify the interacting partner of W43. W271A Protease-VPg mutant showed absence of cleavage activity both in vivo and in trans, with concomitant loss of the 230 nm CD peak. F269A Protease-VPg mutant was partially active. Mutations of the tyrosines did not result in loss of protease activity or the CD peak. Interestingly, H275, though not a part of the exposed aromatic stretch, was shown to be essential for protease activity and contributed significantly to the CD peak. Hence, we conclude that W271 and H275 of the protease domain mediate aromatic stacking interactions with W43 of VPg thereby rendering the protease active.

Item Type:	Journal Article
Publication:	Virology
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	Sesbania mosaic virus;Serine protease;VPg;Natively unfolded protein;Aromatic residues;Histidine;Stacking interactions; Positive CD peak.
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit Division of Biological Sciences > Biochemistry
Date Deposited:	30 Oct 2009 06:02
Last Modified:	19 Sep 2010 04:57
URI:	http://eprints.iisc.ac.in/id/eprint/17554

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