Overnight cultures of the UQ3588 host strain (Table 1) expressing different CRP proteins (C-terminally His-tagged) under IPTG-dependent regulation were diluted in LC medium (see “Experimental Procedures”) supplemented with 50 μg/ml ampicillin, 0–1 mM IPTG, and 0 cAMP (A–C) or 2 mM cAMP (D–F). Open symbols, no IPTG; lightgraysymbols,0.01mM IPTG;darkgraysymbols,0.1mM IPTG;blacksymbols,1mM IPTG. Each strain was grown with shaking at 37 °C and 220 rpm and sampled every hour for the measurement of A600 nm.