Fig 2. Expression of prn in an E. coli degP deletion strain is lethal.

(A) Viability of the E. coli degP null strain versus its parent strain was assessed after transforming plasmids that constitutively express AT variants. Viability was measured by counting colony forming units (CFUs); see Methods. Error bars are standard deviations from three biological repetitions. (B) Growth of the E. coli degP null strain versus its parent strain, with or without IPTG-induction of prn expression. Shown are representative growth curves.