How a Virus Circumvents Energy Barriers to Form Symmetric Shells

• DOI: 10.48550/arxiv.2003.13748
• Publication Date: 2020-01-01
• Authors: Sanaz Panahandeh; Siyu Li; Laurent Marichal; Rafael Leite Rubim; Guillaume Tresset; Roya Zandi
• Keywords: Intrinsically Disordered Proteins; Nucleoprotein

Previous self-assembly experiments on a model icosahedral plant virus have shown that, under physiological conditions, capsid proteins initially bind to the genome through an en masse mechanism and form nucleoprotein complexes in disordered state, which raises questions as how virions are assembled into highly ordered structure host cell. Using small-angle X-ray scattering, we find out that disorder-order transition occurs conditions upon increase protein concentrations. Our cryo-transmission electron microscopy reveals closed spherical shells containing vitro transcribed viral RNA even at pH 7.5, marked contrast with previous observations. We use Monte Carlo simulations explain this shell grows, structures of intermediates distribution pentamers does not belong subgroups become energetically so unfavorable caps can easily dissociate reassemble overcoming energy barriers for formation perfect shells. In addition, monitor growth capsids condition nucleation is dominant pathway show key both pathways lies strength elastic compared other forces system including protein-protein interactions chemical potential free subunits. findings explain, least part, why order different ones.