101. Assembly and disassembly intermediates of maize streak geminivirus
- Author
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David Rodriguez, Margaret I. Boulton, Antonette Bennett, Samantha Lister, Mavis Agbandje-McKenna, and Robert McKenna
- Subjects
Gene Expression Regulation, Viral ,Models, Molecular ,0301 basic medicine ,Protein Conformation ,viruses ,Coat protein ,Zea mays ,Divalent ,03 medical and health sciences ,chemistry.chemical_compound ,Virology ,Low salt ,Maize streak virus ,Geminiviridae ,chemistry.chemical_classification ,biology ,Virus Assembly ,biochemical phenomena, metabolism, and nutrition ,biology.organism_classification ,Plant Leaves ,030104 developmental biology ,Capsid ,chemistry ,Biophysics ,Capsid Proteins ,DNA - Abstract
Maize streak virus (MSV) belongs to the Geminiviridae. Four forms of MSV coat protein (CP) assemblages were isolated from infected plants: geminate capsids, T = 1 icosahedral capsids, pentamers and decamers of CPs. Sequential exposure of geminate capsids to increasing pH, from 4.8 to 7.2 was used to monitor capsid disassembly. The capsids remain intact at pH4.8, disassemble to decamers and pentamers by pH6.4 and aggregate by pH7.2. Similarly, high salt and divalent cations cause disassembly. The disassembly process was reversed in low pH and low salt, but resulted in empty (no DNA) single and geminate capsid assemblies. This is likely due to disruption of CP-DNA interactions under acidic conditions and suggests a mechanism of capsid assembly in which the genome is packaged into preformed empty capsids. The pH assay developed in this study provides a method for characterizing the conditions that are the determinants of geminivirus assembly and disassembly.
- Published
- 2018