Bacteriophage α3

Bacteriophage α3 is a member of the Microviridae, a family of small, single-stranded, icosahedral phages that include ϕX174. These viruses have an ssDNA genome associated with approximately 12 copies of an H pilot protein and 60 copies of a small J DNA-binding protein. The surrounding capsid consists of 60 F coat proteins decorated with 12 pentameric spikes of G protein. Assembly proceeds via a 108 S empty procapsid that requires the external D and internal B scaffolding proteins for its formation.