Table 1.

Proteins involved in ϕX174 assembly.

Protein	kDa	No. of amino acids	Function
F	48.4	426	Major capsid protein; has virus structural β-barrel fold plus two large irregular insertions involved in monomer–monomer interactions.
G	19.0	175	Pentamers form 12 spikes on virion; has virus structural β-barrel motif.
J	4.2	37	Protein required for packing ssDNA into virion; has extended structure on internal face of the F protein in the virion.
H	34.4	328*	12 copies per virion; is disordered in X-ray studies; ‘pilot’ protein which enters E. coli during DNA injection.
B	13.8	120*	Scaffolding protein used in formation of procapsid.
D	16.9	152*	Scaffolding protein used in formation of procapsid; aggregates as a tetramer.

^*Based on the DNA sequence.