Authors: Y. Ohtsuka, D. Nakai, F. Coulibaly, E. Chiu, P. Metcalf, H. Mori
Affilation: Kyoto Institute of Technology, Japan
Pages: 292 - 295
Keywords: virus, polyhedra, protein, immobilization
Cypoviruses, a member of the family Reoviridae, are one group of insect virus that produce micrometer-sized protein crystals called cytoplasmic polyhedra. Many virus particles are occluded in polyhedra to protect them against extracellular environment. Recently we have developed a novel method for protein immobilization into polyhedra. It is possible to use these polyhedra to device ultra-stable protein nanocontainers. However, a weak point of the protein nanocontainers is that polyhedra dissolve only in very high pH condition (pH > 10). It seems important now to carry out structure-based engineering of polyhedrin to derive mutants for multiple purposes, for example, such that the crystals can be dissolved at pH values that are not as drastic. We have identified a cluster of tyrosine at a packing contact, deprotonation of which is likely to cause disruption of the lattice at very alkaline pH. It is perhaps possible to test the effect of substitution of these tyrosine residues by other amino acids. We show that the substitutions of some residues in a cluster of tyrosine lead to modify a solubility of polyhedra. The results suggest that the modified polyhedra can serve as the basis for the development of robust and versatile nanoparticles for biotechnological applications.