Figure 3. Binding of RNA oligomers to RsmE measured by ITC. Typical ITC experiments of RsmE (7.6 μM of homodimer in cell) with pltA 19-mer RNA (164.1 μM in syringe) and of RsmE (7.5 μM) with pltA+U 20-mer RNA (150.3 μM) are shown in (A and B), respectively. Both oligomers bound specifically to RsmE and exhibited a biphasic binding isotherm typical of a cooperative sequential binding mechanism. The raw data for consecutive injections of RNA to RsmE (top panels) was integrated and corrected for the heat of dilution and plotted against the (oligomer)/(RsmE) ratio (lower panels). The solid line represents the best least-squares fit to the data using a sequential binding model. The corresponding results are presented in Table 2.