This is a family of proteins from single-stranded DNA bacteriophages. Protein F is the major capsid component, sixty copies of which are found in the virion.

1: Atomic structure of the degraded procapsid particle of the bacteriophage G4: induced structural changes in the presence of calcium ions and functional implications. McKenna R, Bowman BR, Ilag LL, Rossmann MG, Fane BA; J Mol Biol 1996;256:736-750. PMID:8642594