© Elsevier, 2011.Principles of Molecular Virology Virus Particles Why do viruses make particles to contain the genome? Symmetry allows particles to assemble using only the information contained within the particle The main types of virus particle – – helical – icosahedral – complex structures

© Elsevier, 2011.Principles of Molecular Virology Virus Particles

© Elsevier, 2011.Principles of Molecular Virology Capsid Symmetry & Virus Architecture 1957: Fraenkel-Conrat and Williams - when mixtures of purified tobacco mosaic virus (TMV) RNA and coat protein are incubated together, virus particles form Forces that drive the assembly of virus particles include hydrophobic and electrostatic interactions Rarely are covalent bonds involved in holding together subunits

© Elsevier, 2011.Principles of Molecular Virology Helical Capsids - TMV P = µ x p

© Elsevier, 2011.Principles of Molecular Virology Bacteriophage M13

© Elsevier, 2011.Principles of Molecular Virology Rhabdovirus particle

© Elsevier, 2011.Principles of Molecular Virology Icosahedral (Isometric) Capsids

© Elsevier, 2011.Principles of Molecular Virology Triangulation number

© Elsevier, 2011.Principles of Molecular Virology Geminivirus - twinned icosahedra

© Elsevier, 2011.Principles of Molecular Virology Picornavirus Particle

© Elsevier, 2011.Principles of Molecular Virology Eight-strand antiparallel  -barrel

© Elsevier, 2011.Principles of Molecular Virology Proteolytic processing of picornavirus capsid proteins

© Elsevier, 2011.Principles of Molecular Virology Budding of enveloped virus particles

© Elsevier, 2011.Principles of Molecular Virology Envelope proteins

© Elsevier, 2011.Principles of Molecular Virology Complex Virus Structures - Poxvirus particle

© Elsevier, 2011.Principles of Molecular Virology Assembly pathway of bacteriophage T4

© Elsevier, 2011.Principles of Molecular Virology Baculovirus particles

© Elsevier, 2011.Principles of Molecular Virology Mimivirus

© Elsevier, 2011.Principles of Molecular Virology Assembly of tobacco mosaic virus (TMV) particles

© Elsevier, 2011.Principles of Molecular Virology Summary There are a number of repeated structural patterns found in many different virus groups Virus particles are not inert structures Virus particles are designed to interact with host cell receptors to initiate the process of infection

© Elsevier, 2011.Principles of Molecular Virology Further Reading Brown, J.C., Newcomb, W.W. and Wertz, G.W. (2010) Helical Virus Structure: The Case of the Rhabdovirus Bullet. Viruses 2: Cherwa, J.E. and Fane, B.A. (2009) Complete Virion Assembly with Scaffolding Proteins Altered in the Ability To Perform a Critical Conformational Switch. J Virol. 83 (15): 7391–7396 Hemminga, M.A., et al. (2010) Viruses: incredible nanomachines. New advances with filamentous phages. Eur Biophys J. 39(4): Hutchinson, E.C. et al. (2010) Genome packaging in influenza A virus. J Gen Virol : Ivanovska, I.L. et al. (2004) Bacteriophage capsids: tough nanoshells with complex elastic properties. Proceedings of the National Academy of Science USA, 101: 7600–7605 Klug, A. (1999) The tobacco mosaic virus particle: structure and assembly. Philos Trans R Soc Lond B Biol Sci. March 29; 354 (1383): 531–535 Mannige, R.V. and Brooks, C.L. (2010) Periodic Table of Virus Capsids: Implications for Natural Selection and Design. PLoS ONE 5(3): e9423 Maurer-Stroh, S. and Eisenhaber, F. (2004) Myristoylation of viral and bacterial proteins. Trends in Microbiology, 12: 178– 185 McKenna, R. et al. (1992) Atomic structure of single-stranded DNA bacteriophage φX174 and its functional implications. Nature, 355: 137–143 Roberts, K.L. and Smith, G.L. (2008) Vaccinia virus morphogenesis and dissemination. Trends in Microbiology 16(10): Rohrmann, G.F. (2008) Baculovirus Molecular Biology. NCBI Bookshelf Xiao C, et al. (2009) Structural Studies of the Giant Mimivirus. PLoS Biol 7(4): e