Dimerization of Recombinant Tobacco Mosaic Virus Movement Protein

AUTOR(ES)
FONTE

American Society for Microbiology

RESUMO

The p30 movement protein (MP) is essential for cell-to-cell spread of tobacco mosaic virus in planta. We used anion-exchange chromatography and preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) to obtain highly purified 30-kDa MP, which migrated as a single band in native PAGE. Analytical ultracentrifugation suggested that the protein was monodisperse and dimeric in the nonionic detergent n-octyl-β-d-glucopyranoside. Circular dichroism (CD) spectroscopy showed that the detergent-solubilized protein contained significant α-helical secondary structure. Proteolysis of the C-tail generated a trypsin-resistant core that was a mixture of primarily monomers and some dimers. We propose that MP dimers are stabilized by electrostatic interactions in the C terminus as well as hydrophobic interactions between putative transmembrane α-helical coiled coils.

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