Cowpea Chlorotic Mottle Virus: Difference between revisions
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'''Significance of Structural Transitions ''' | '''Significance and Applications of CCMV Structural Transitions ''' | ||
CCMV is relevant to mammalian | In the field of virology, CCMV is relevant to mammalian research due to the similarity of structural transitions in human polio virus, of the picornaviridae family<ref name=Speir>PMID:7743132</ref> | ||
(another naked icosahedral virus). | (another naked icosahedral virus). | ||
More influentially, the properties of the capsid allow the virus to be exploited in nanotechnology. Capsid proteins can be obtained through two main strategies. | |||
First, virus can be directly extracted from plant leaves in high yields (1 kg of infected plant tissue can yield 1–2 g of virus<ref name=Liepold>PMID:Liepold16280622</ref>). By raising the pH to 7.5 and dissociating the capsid into dimers, the protein can be isolated from the RNA. The purified proteins can then self-assemble into functional virus-like particles when restored to more acidic conditions. | First, virus can be directly extracted from plant leaves in high yields (1 kg of infected plant tissue can yield 1–2 g of virus<ref name=Liepold>PMID:Liepold16280622</ref>). By raising the pH to 7.5 and dissociating the capsid into dimers, the protein can be isolated from the RNA. The purified proteins can then self-assemble into functional virus-like particles when restored to more acidic conditions. | ||
A more modern strategy involves the use of recombinant DNA technology. In this approach, the capsid-encoding genes of the virus can be transfected into a yeast expression vector.<ref name=Liepold>PMID:Liepold16280622</ref>) As the yeast replicate, they amplify the number of protein producing units, and the secreted protein products can be readily collected from the media. The major benefit to this method, aside from high yield production, is that the genome can be modified prior to insertion into the vector. This can | A more modern strategy involves the use of recombinant DNA technology. In this approach, the capsid-encoding genes of the virus can be transfected into a yeast expression vector.<ref name=Liepold>PMID:Liepold16280622</ref>) As the yeast replicate, they amplify the number of protein producing units, and the secreted protein products can be readily collected from the media. The major benefit to this method, aside from high yield production, is that the genome can be modified prior to insertion into the vector. This can be used to produce capsid subunits with differing chemical properties. Such a procedure was performed by Dr. J. J. L. M. Cornelissen in the Netherlands. He attempted to solve the problem of pH sensitivity in reactants, particularly enzymes, and the acidic conditions required for capsid stability. It was found that nickel atoms could stabilize the capsid at pH 7.5. This was a promising alternative to the large polyelectrolytes that were used to stabilize the capsid because they often filled the capsid and limited reagent concentration. | ||
Histidine residues were able to readily coordinate with nickel, and this property was used to purify the modified proteins from the media of their expression vectors. This purification was performed with a column of nickel atoms immobilized to a resin enriched with a metal chelating agent (NTA). Once the proteins were isolated, a experimental, pH-sensitive, protein (EGFP) was coupled with the capsomeres. | |||
The metal ion induced stabilization was likely due to a different mechanism than older polyelectrolyte methods since the metal ions are substantially smaller than polyelectrolytes, and they are positively charged. | |||
The field of nanovirology using these cage structures has branched into both biomedical sciences and physical virology. | |||
