The binding of divalent cations to tobacco mosaic virus and to some isometric plant viruses

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dc.contributor.advisorDurham, Tonyen_ZA
dc.contributor.authorHendry, Donald Arthuren_ZA
dc.date.accessioned2016-03-17T07:12:12Z
dc.date.available2016-03-17T07:12:12Z
dc.date.issued1977en_ZA
dc.descriptionBibliography: pages 202-212.en_ZA
dc.description.abstractThe binding of divalent cations (particularly calcium and magnesium) to strains of tobacco mosaic virus (TMV) and their isolated proteins was investigated, using equilibrium dialysis and potentiometric titration, in an attempt to elucidate the role of divalent cations in virus stabilisation. It was found that dissociation of bound calcium ions from TMV is apparently a necessary but insufficient condition for in vitro virus disassembly. TMV and the closely related strain, Y-TAMV, possessed three groups per protein subunit which titrated near neutral pH and which showed significant metal ion binding. The tightest of the three calcium binding sites, which was absent on the RNA-free protein, had a computed pKH of 8.3 and pKCa of 5.2 and had a significantly higher affinity for Ca⁺² over Mg⁺² This group thus had some of the characteristics to be expected for a calcium-mediated switch controlling in vivo virus disassembly, and possibly controlled the in vitro alkaline degradation of TMV as well. Both the U2 and cowpea strains of TMV bound one additional metal ion per protein subunit relative to vulgare, this binding site being retained by the polymerised proteins. However, calcium ions stabilised the polymerised forms of the proteins of all four TMV strains at pH values where depolymerisation would normally have occurred. Both bromegrass mosaic virus and turnip crinkle virus bound calcium ions, which stabilised compact forms of these viruses. The phenomenon of cation binding is thus not limited to TMV. In the light of published evidence, it appears that most if not all plant viruses are able to bind divalent cations, which thus represent a hitherto disregarded stabilising element.en_ZA
dc.identifier.apacitationHendry, D. A. (1977). <i>The binding of divalent cations to tobacco mosaic virus and to some isometric plant viruses</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology. Retrieved from http://hdl.handle.net/11427/17879en_ZA
dc.identifier.chicagocitationHendry, Donald Arthur. <i>"The binding of divalent cations to tobacco mosaic virus and to some isometric plant viruses."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology, 1977. http://hdl.handle.net/11427/17879en_ZA
dc.identifier.citationHendry, D. 1977. The binding of divalent cations to tobacco mosaic virus and to some isometric plant viruses. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Hendry, Donald Arthur AB - The binding of divalent cations (particularly calcium and magnesium) to strains of tobacco mosaic virus (TMV) and their isolated proteins was investigated, using equilibrium dialysis and potentiometric titration, in an attempt to elucidate the role of divalent cations in virus stabilisation. It was found that dissociation of bound calcium ions from TMV is apparently a necessary but insufficient condition for in vitro virus disassembly. TMV and the closely related strain, Y-TAMV, possessed three groups per protein subunit which titrated near neutral pH and which showed significant metal ion binding. The tightest of the three calcium binding sites, which was absent on the RNA-free protein, had a computed pKH of 8.3 and pKCa of 5.2 and had a significantly higher affinity for Ca⁺² over Mg⁺² This group thus had some of the characteristics to be expected for a calcium-mediated switch controlling in vivo virus disassembly, and possibly controlled the in vitro alkaline degradation of TMV as well. Both the U2 and cowpea strains of TMV bound one additional metal ion per protein subunit relative to vulgare, this binding site being retained by the polymerised proteins. However, calcium ions stabilised the polymerised forms of the proteins of all four TMV strains at pH values where depolymerisation would normally have occurred. Both bromegrass mosaic virus and turnip crinkle virus bound calcium ions, which stabilised compact forms of these viruses. The phenomenon of cation binding is thus not limited to TMV. In the light of published evidence, it appears that most if not all plant viruses are able to bind divalent cations, which thus represent a hitherto disregarded stabilising element. DA - 1977 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1977 T1 - The binding of divalent cations to tobacco mosaic virus and to some isometric plant viruses TI - The binding of divalent cations to tobacco mosaic virus and to some isometric plant viruses UR - http://hdl.handle.net/11427/17879 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/17879
dc.identifier.vancouvercitationHendry DA. The binding of divalent cations to tobacco mosaic virus and to some isometric plant viruses. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology, 1977 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/17879en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Molecular and Cell Biologyen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherMicrobiologyen_ZA
dc.titleThe binding of divalent cations to tobacco mosaic virus and to some isometric plant virusesen_ZA
dc.typeDoctoral Thesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnamePhDen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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