The role of inter-subunit ionic interactions in the sssembly of Physalis mottle tymovirus

Umashankar, M and Murthy, MRN and Singh, SA and Rao, Appu AG and Savithri, HS (2006) The role of inter-subunit ionic interactions in the sssembly of Physalis mottle tymovirus. In: Archives of Virology, 151 (10). pp. 1917-1931.

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Abstract

Physalis mottle tymovirus (PhMV) is a small spherical plant virus with its RNA genome encapsidated in a protein shell made of 180 identical coat protein (CP) subunits. The amino acid residues involved in two interfacial salt bridges, Asp-83/Arg-159 and Arg-68/Asp-150 and Lys-153, were targeted for mutagenesis with a view to delineate the role of interfacial ionic interactions in the subunit folding and assembly of the virus. R159A and D83A-R159A recombinant CP (rCP) mutants formed stable T=3 capsids, indicating that the D83-R159 interfacial salt bridge is dispensable for the folding and assembly of PhMV. However, D150A and R68Q-D150A mutant rCPs were present in the insoluble fraction, suggesting that the R68-D150 interfacial salt bridge is crucial for subunit folding and assembly. Similarly, K153Q, D83A-K153Q, and H69AK153Q mutant rCPs were present in the insoluble fraction. Interestingly, the R68Q-D150A, D83A-K153Q, and H69A-K153Q double mutant rCPs could be refolded into partially folded soluble heterogeneous aggregates of 14–16 S. The results further confirm our earlier observation that subunit folding and assembly are concerted events in PhMV.

Item Type:	Journal Article
Publication:	Archives of Virology
Publisher:	Springer
Additional Information:	Copyright of this article belongs to Springer.
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit Division of Biological Sciences > Biochemistry
Date Deposited:	13 Feb 2007
Last Modified:	19 Sep 2010 04:32
URI:	http://eprints.iisc.ac.in/id/eprint/9039

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