Figure 3. Complementation assay for functionality of mutant forms of the major capsid protein gp5.
The photographs show bacterial lawns of amber non-suppressing strains expressing gp5 of the indicated genotype. Each lawn was spotted with a dilution series of HK97 carrying an amber mutation in gene 5. Clearing of the lawn at higher dilutions of the infecting phage (more leftward spots) indicates positive complementation. Mutant D108A complements as well as wild type, but mutants V163D (the focus of this study) and K169Y (missing the crosslink reactant lysine) both fail to complement.