Mutational analysis of CarDNt interactions with RNAP-β.

<p>(<b>A</b>) Ribbon representation of the average CarD_1–72 NMR solution structure showing residue side chains (labeled in green) tested by site-directed mutagenesis, whose equivalents in CdnL (labeled in magenta) contact RNAP-β (see text). The sidechains are represented based on the CarD_1–72 and CdnL backbones corresponding to an overlay of their β2-β3-β4 segments. The structure was generated using MOLMOL. (<b>B</b>) BACTH analysis (spot assay) of the interaction between the indicated CarDNt mutants expressed in pKT25 and CarG in pUT18C. (<b>C</b>) BACTH analysis of the interaction between the indicated CarDNt mutants expressed in pKT25 and Mxβ_19–148 in pUT18C. (<b>D</b>) BACTH analysis of the interaction between the indicated Mxβ_19–148 mutants expressed in pUT18C versus CarDNt in pKT25. In <b>C</b> and <b>D</b> the mean and standard error of three independent experiments are shown.