This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Google Scholar
Right arrow Articles by Cherwa, J. E.
Right arrow Articles by Fane, B. A.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Cherwa, J. E., Jr.
Right arrow Articles by Fane, B. A.

 Previous Article  |  Next Article 

Journal of Virology, August 2009, p. 7391-7396, Vol. 83, No. 15
0022-538X/09/$08.00+0     doi:10.1128/JVI.00479-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Complete Virion Assembly with Scaffolding Proteins Altered in the Ability To Perform a Critical Conformational Switch{triangledown}

James E. Cherwa Jr. and Bentley A. Fane*

Department of Plant Sciences and BIO5 Institute, University of Arizona, Tucson, Arizona 85719

Received 6 March 2009/ Accepted 18 May 2009

In the {phi}X174 procapsid, 240 external scaffolding proteins form a nonquasiequivalent lattice. To achieve this arrangement, the four structurally unique subunits must undergo position-dependent conformational switches. One switch is mediated by glycine residue 61, which allows a 30° kink to form in {alpha}-helix 3 in two subunits, whereas the helix is straight in the other two subunits. No other amino acid should be able to produce a bend of this magnitude. Accordingly, all substitutions for G61 are nonviable but mutant proteins differ vis-à-vis recessive and dominant phenotypes. As previously reported, amino acid substitutions with side chains larger than valine confer dominant lethal phenotypes. Alone, these mutant proteins appear to have little or no biological activity but rather require the wild-type protein to interact with other structural proteins. Proteins with conservative substitutions for G61, serine and alanine, have now been characterized. Unlike the dominant lethal proteins, these proteins do not require wild-type subunits to interact with other viral proteins and cause assembly defects reminiscent of those conferred by the lethal dominant proteins in concert with wild-type subunits. Although atomic structures suggest that only a glycine residue can provide the proper torsion angle for assembly, mutants that can productively utilize the altered external scaffolding proteins were isolated, and the mutations were mapped to the coat and internal scaffolding proteins. Thus, the ability to isolate strains that could utilize the single mutant D protein species would not have been predicted from past structural analyses.

* Corresponding author. Mailing address: The BIO5 Institute, Keating Building, University of Arizona, Tucson, AZ 85719. Phone: (520) 626-6634. Fax: (520) 621-6366. E-mail: bfane{at}u.arizona.edu

{triangledown} Published ahead of print on 27 May 2009.

Journal of Virology, August 2009, p. 7391-7396, Vol. 83, No. 15
0022-538X/09/$08.00+0     doi:10.1128/JVI.00479-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Cherwa, J. E. Jr., Sanchez-Soria, P., Members of the University of Arizona Virology Labo, , Wichman, H. A., Fane, B. A. (2009). Viral Adaptation to an Antiviral Protein Enhances the Fitness Level to Above That of the Uninhibited Wild Type. J. Virol. 83: 11746-11750 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»