SV40 VP1 major capsid protein in its self-assembled form allows VP1 pentamers to coat various types of artificial beads in vitro regardless of their sizes and shapes

• Monomeric VP1 pentamers of simian virus 40 coat artificial beads larger than natural capsids.
• Polystyrene beads (100, 200, and 500 nm in diameter) can be covered by VP1 pentamers.
• Silica beads can also be covered by VP1 pentamers.
• VP1 pentamers can also coat angular-shaped magnetite-particle and rough-shaped liposomes.
• The self-reassembly property of VP1 may allow it to coat various artificial beads, regardless of their sizes or shapes.

The icosahedral capsid structure of simian virus 40 (diameter, 45 nm) consists of 72 pentameric subunits, with each subunit formed by five VP1 molecules. Electron microscopy, immuno-gold labeling, and ζ-potential analysis showed that purified recombinant VP1 pentamers covered polystyrene beads measuring 100, 200, and 500 nm in diameter, as well as silica beads. In addition to covering spherical beads, VP1 pentamers covered cubic magnetite beads, as well as the distorted surface structures of liposomes. These findings indicate that VP1 pentamers could coat artificial beads of various shapes and sizes larger than the natural capsid. Technology based on VP1 pentamers may be useful in providing a capsid-like surface for enclosed materials, enhancing their stability and cellular uptake for drug delivery systems.