N-terminal deletions of the phiX174 external scaffolding protein affect the timing and fidelity of assembly.

The first alpha-helices of Microviridae external scaffolding proteins function as coat protein substrate specificity domains. Mutations in this helix can lengthen the lag phase before progeny production. 5' deletion genes, encoding N-terminal deletion proteins, were constructed on plasmids and in the øX174 genome.