The crystal structure of cricket paralysis virus: the first view of a new virus family

Numerous small, RNA-containing insect viruses are currently classified as p icornaviruses, or as 'picorna-like', since they superficially resemble the true picornaviruses. Considerable evidence now suggests that several of the se viruses are members of a distinct family. We have determined the gene se quence of the capsid proteins and the 2.4 Angstrom resolution crystal struc ture of the cricket paralysis virus. While the genome sequence indicates th at the insect picorna-like viruses represent a distinct lineage compared to true picornaviruses, the capsid structure demonstrates that the two groups are related. These viral genomes are, thus, best viewed as composed of exc hangeable modules that have recombined.