Effects of genetic modification the C-terminal needle domain.

aSalmonella lysogens are listed that were induced to prepare stocks of the phages in the table; the amino acid changes in the L-glutamate binding site of the needle are shown after the Sf6-hybrid needle phage strain names (UB-1919 to 1929). bLysogens were induced with mitomycin C and titered on Salmonella strain UB-0002; average results from several replicates are shown. cPhage particles were purified through CsCl step gradients [68], and phage titers were determined on Salmonella strain UB-0002. Relative PFU/particle ratios were calculated by normalization to UB-1790 titer (PFU) and to the intensity of quantified coat protein bands in SDS electrophoresis gels and/or OD280 (particles). Several replicates were performed for each phage with similar results, and the average value is shown. dThe prophages all have the following genetic background: P22 26::Sf6-3, sieA–Δ1, 15–ΔSC302::KanR, 13–amH101 (see table 2).