This Article Full Text Full Text (PDF) Other Versions of this Article: JVI.00594-07v1 81/20/11075    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Hyun, J.-K. Articles by Mitra, A. K. Search for Related Content PubMed PubMed Citation Articles by Hyun, J.-K. Articles by Mitra, A. K.

 Previous Article  |  Next Article 

Journal of Virology, October 2007, p. 11075-11083, Vol. 81, No. 20
0022-538X/07/$08.00+0     doi:10.1128/JVI.00594-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

The Structure of a Putative Scaffolding Protein of Immature Poxvirus Particles as Determined by Electron Microscopy Suggests Similarity with Capsid Proteins of Large Icosahedral DNA Viruses

Jae-Kyung Hyun,^1, Fasséli Coulibaly,^1, Adrian P. Turner,¹ Edward N. Baker,¹ Andrew A. Mercer,² and Alok K. Mitra^1*

School of Biological Sciences, University of Auckland, Postal Bag 92019, Auckland, New Zealand,¹ Department of Microbiology and Immunology, University of Otago, Post Office Box 56, Dunedin, New Zealand²

Received 21 March 2007/ Accepted 20 July 2007

Orf virus, the prototype parapoxvirus, is responsible for contagious ecthyma in sheep and goats. The central region of the viral genome codes for proteins highly conserved among vertebrate poxviruses and which are frequently essential for viral proliferation. Analysis of the recently published genome sequence of orf virus revealed that among such essential proteins, the protein orfv075 is an orthologue of D13, the rifampin resistance gene product critical for vaccinia virus morphogenesis. Previous studies showed that D13, arranged as "spicules," is necessary for the formation of vaccinia virus immature virions, a mandatory intermediate in viral maturation. We have determined the three-dimensional structure of recombinant orfv075 at 25-Å resolution by electron microscopy of two-dimensional crystals. orfv075 organizes as trimers with a tripod-like main body and a propeller-like smaller domain. The molecular envelope of orfv075 shows unexpectedly good agreement to that of a distant homologue, VP54, the major capsid protein of Paramecium bursaria Chlorella virus type 1. Our structural analysis suggests that orfv075 belongs in the double-barreled capsid protein family found in many double-stranded DNA icosahedral viruses and supports the hypothesis that the nonicosahedral poxviruses and the large icosahedral DNA viruses are evolutionarily related.

Published ahead of print on 1 August 2007.

Both authors contributed equally to the work.