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A Molecular Switch in the Capsid Protein Controls the Particle Polymorphism in an Icosahedral Virus

Lokesh, GL and Gowri, TDS and Satheshkumar, PS and Murthy, MRN and Savithri, HS (2002) A Molecular Switch in the Capsid Protein Controls the Particle Polymorphism in an Icosahedral Virus. In: Virology, 292 (2). pp. 211-223.

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The recombinant coat protein (CP) of Sesbania mosaic virus (SeMV; genus Sobemovirus) was found to self-assemble into capsids encapsidating 23S rRNA and CP mRNA in Escherichia coli. The CP lacking 22 amino acids from the N-terminus assembled into stable T = 3 capsids that appeared similar to SeMV, indicating that the N-terminal 22 amino acid residues are dispensable for T = 3 assembly. Two distinct capsids, T = 1 and pseudo T = 2, were observed when the N-terminal 36 amino acids encompassing the arginine-rich motif (N-ARM) were removed. Only T = 1 particles were observed upon deletion of 65 amino acids from the N-terminus, which also included the sequence element for the β-annulus. These results reveal that N-ARM acts as a molecular switch in regulating T = 3 assembly. Formation of stable pseudo T = 2 particles shows that pentamers of AB dimers could nucleate assembly at icosahedral-5-folds. Capsids assembled from the N-terminally truncated proteins also encapsidated 23S rRNA and CP mRNA, suggesting the presence of sites outside the N-terminal 65 residues that may be involved in RNA–protein interactions.

Item Type: Journal Article
Publication: Virology
Publisher: Elsevier
Additional Information: Copyright of this article belongs to Elsevier.
Keywords: Icosahedral virus;Virus assembly;Coat protein;Sobemovirus;Sesbania mosaic virus
Department/Centre: Division of Biological Sciences > Molecular Biophysics Unit
Division of Biological Sciences > Biochemistry
Date Deposited: 09 Oct 2007
Last Modified: 19 Sep 2010 04:40
URI: http://eprints.iisc.ac.in/id/eprint/12166

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