Cells containing PsrfA-lacZ were grown in defined minimal medium and transcription of srfA-lacZ was monitored by measuring β-galactosidase specific activity at times throughout growth. Where indicated, 1 mM IPTG was added to cultures at the time of inoculation to induce expression of Pspank-(Ec)-sspB. β-galactosidase specific activity is plotted as a function of cell density (OD600).
The effects of ssrA degradation tags on ComA activity in the absence of any adaptor protein; KG1343 (wild type, no ssrA tag; open diamonds); KG1205 (ComA-(Ec)ssrA-ALGG+4 (ssrA*); “X”); and KG1235 (ComA-(Ec)ssrA-ADAN+4; dashed line).
The effects of basal (uninduced) expression from Pspank-(Ec)sspB on ComA-(Ec)ssrA* activity: KG1178 (wild type Pspank-(Ec)sspB) without IPTG, filled squares; with IPTG, open squares. KG1180 (Pspank(T-35C)-(Ec)sspB) without IPTG, black triangles; with IPTG, open triangles. KG1177 (Pspank(T-7C)-(Ec)sspB) without IPTG, black circles; with IPTG open circles.