Authors: H. Mori, H. Ijiri, E. Kotani
Affilation: Kyoto Institute of Technology, Japan
Pages: 254 - 257
Keywords: virus, polyhedra, protein, immobilization
Certain insect viruses encode a protein called polyhedrin that forms polyhedric crystals, or polyhedra, within an infected cell. The virus particles, or virions, are protected within these polyhedra and can remain infectious for years outside cells, even in harsh environmental conditions. The polyhedra break down and release the virus only when ingested into the very alkaline environment of the midgut of insect larvae (pH 10–11), resulting in infection of a new host. The genus Cypovirus is members of the family Reoviridae that infect insect larvae producing polyhedra in the cytoplasm of mid-gut epithelial cells. Recently the atomic structure of cypovirus polyhedra was determined by using a synchrotron microbeam to collect X-ray diffraction data. It was elucidated that polyhedra are made from trimeric building blocks of the polyhedrin interlocked into a tight scaffold generated by the amino-terminal alpha-helix. These structural analysis of polyhedra and virus particles of cypovirus was related to the development of a platform for the design of protein nanocontainers, leading to develop a general method to stabilize proteins by incorporating them into modified polyhedra. I describe these modified polyhedra or ‘nano-containers’, which have a variety of applications, including the development of stabilized growth factors for cell-culture.