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The Assembly Pathway of an Icosahedral Single-Stranded Virus Depends on the Strength of Inter-Subunit Attractions

TitleThe Assembly Pathway of an Icosahedral Single-Stranded Virus Depends on the Strength of Inter-Subunit Attractions
Publication TypeJournal Article
Year of Publication2014
AuthorsGarmann, RF, Comas-Garcia, M, Gopal, A, Knobler, CM, Gelbart, WM
JournalJournal of Molecular Biology
Volume426
Pagination1050 - 1060
ISSN0022-2836
Keywordspackaging
Abstract

Abstract The strength of attraction between capsid proteins (CPs) of cowpea chlorotic mottle virus (CCMV) is controlled by the solution pH. Additionally, the strength of attraction between \{CP\} and the single-stranded \{RNA\} viral genome is controlled by ionic strength. By exploiting these properties, we are able to control and monitor the in vitro co-assembly of \{CCMV\} \{CP\} and single-stranded \{RNA\} as a function of the strength of CP–CP and CP–RNA attractions. Using the techniques of velocity sedimentation and electron microscopy, we find that the successful assembly of nuclease-resistant virus-like particles (VLPs) depends delicately on the strength of CP–CP attraction relative to CP–RNA attraction. If the attractions are too weak, the capsid cannot form; if they are too strong, the assembly suffers from kinetic traps. Separating the process into two steps—by first turning on CP–RNA attraction and then turning on CP–CP attraction—allows for the assembly of well-formed \{VLPs\} under a wide range of attraction strengths. These observations establish a protocol for the efficient in vitro assembly of \{CCMV\} \{VLPs\} and suggest potential strategies that the virus may employ in vivo.

URLhttp://www.sciencedirect.com/science/article/pii/S0022283613006621
DOI10.1016/j.jmb.2013.10.017
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