Speaker
Jade Forwood
(CSU)
Description
The assembly and regulation of viral capsid proteins into highly ordered macromolecular complexes is essential for viral replication. Recent reports have elucidated the ability of capsids to switch between T1 and T3 symmetry, however little is known regarding how capsid proteins can switch between smaller, non-icosahedral macromolecular complexes. Here we utilize crystal structures of the capsid protein from the smallest and simplest of all known viruses capable of autonomously replicating in animal cells, circoviruses, to establish structural and mechanistic insights into capsid morphogenesis and regulation. The beak and feather disease virus is responsible for infecting critically endangered parrots, and remarkably, like many circoviruses, these viruses encode only two genes, a capsid protein, and a replication initiation protein. The capsid protein forms distinct macromolecular assemblies during replication and here we elucidate these structures at high resolution, showing that these complexes reverse the exposure of the N-terminal arginine rich domain responsible for DNA-binding and nuclear localization. We show that assembly of these complexes is regulated by single-stranded DNA (ssDNA), and provide a structural basis of capsid assembly around single stranded DNA, highlighting novel binding interfaces distinct from the highly positively charged N-terminal ARM domain. These structures of the world’s smallest viral capsid assemblies serve as an important basis for enhancing our understanding viral capsid assembly and regulation.
Subir Sarker1,2, María C. Terrón3, Yogesh Khandokar4, David Aragão5, Joshua M. Hardy6, Mazdak Radjainia6, Manuel Jiménez-Zaragoza7, Pedro J. de Pablo7,8, Fasséli Coulibaly6, Daniel Luque Buzo3, Shane R. Raidal1,2, Jade K. Forwood2,4
1 School of Animal and Veterinary Sciences, Charles Sturt University, Boorooma Street, Wagga Wagga, New South Wales 2678, Australia,
2 Graham Centre for Agricultural Innovation (NSW Department of Primary Industries and Charles Sturt University), Boorooma Street, Wagga Wagga, New South Wales 2678, Australia
3 Centro Nacional de Microbiología/ISCIII, Majadahonda, 28220 Madrid, Spain
4 School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, New South Wales, 2678, Australia
5 Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia
6 Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
7 Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain
8 Insituto de Física de la Materia Condensada (IFIMAC), Universidad Autónoma de Madrid,28049 Madrid, Spain
| Are you an ECR? (<5 yrs</br>since PhD/Masters) | No |
|---|---|
| Do you wish to take part in</br>the Student Poster Slam? | No |
| What is your gender? | Female |
| Are you a student? | No |
Primary author
Jade Forwood
(CSU)
