Figure 2. The phage major head protein activates Thoeris in vivo.
(A) Growth of S. aureus RN4220 harboring plasmids carrying either an incomplete (thsB1/B2) or full (thsA/B1/B2) Thoeris operon in the absence or presence of a second plasmid expressing Mhp, determined as the OD600 of the cultures after infection with Φ80α-vir or Φ80α-vir(mhpV273A) at MOI 1. Mean of +/− S.D. of three biological replicates is reported. (B) Measure of % remaining NAD+/NADH (NAD), calculated as the ratio of the concentration of NAD+ and NADH detected in staphylococci harboring a plasmid carrying a full (thsA/B1/B2) Thoeris operon, to the value detected in the presence of an incomplete (thsB1/B2) system, after induction of the ΦNM1 prophage with MMC. Lysogens induced carried either wild-type or mutant prophages with deletions in different genes involved in capsid formation. Mean of +/− S.D. of three biological replicates is reported; p value was obtained using an unpaired, two-tailed, t-test. (C) Same as (B) after induction of wild-type and Δgp43 ΦNM1 prophages, in the presence of a plasmid that expresses Mhp. (D) Same as (B) but after IPTG induction of expression of plasmid-encoded wild-type, V273A or W84K Mhp. (E) Enumeration of CFU/ml after induction of the Φ80α prophage with MMC present in lysogens harboring plasmids carrying either an incomplete (thsB1/B2) or full (thsA/B1/B2) Thoeris operon. Mean of +/− S.D. of three biological replicates is reported; p value was obtained using an unpaired, two-tailed, t-test. (F) Growth of S. aureus RN4220 harboring plasmids carrying either an incomplete (thsB1/B2) or full (thsA/B1/B2) Thoeris operon in the presence of a second plasmid expressing either wild-type or V273A Mhp, determined as the OD600 of the cultures after addition of IPTG. Mean of +/− S.D. of three biological replicates is reported.