TABLE 2.

Ability of plasmids encoding gene 4 proteins to complement T7Δ4 phage for growth The ability of the plasmids encoding gene 4 variants to support the growth of T7Δ4 in E. coli was examined. The number of plaques formed by plasmids harboring the wild-type gene 4 protein is normalized to 1. The relative efficiency of plating obtained with the mutated gene 4 constructs were determined by the number of plaques (PFU) formed by the mutated gene 4 constructs divided by the PFU of wild type gene 4. Efficiency of plating of ≤10^–9 corresponds to the gene 4 construct unable to complement the T7Δ4 growths in the host bacteria.

pET11b:gp4 construct	Efficiency of plating T7Δ4
Wild type	1
R363A	0.023
R504A	1
R363A/R504A	≤10–9
S319T	0.6
S319A	≤10–9
R504A/S319T	0.1