Figure 2. DNA affinity of wt and mutant CBC preparations.
(A, B, C) Surface plasmon resonance-binding analysis of wt (panel 1) and HapEP88L-mutant Aspergillus nidulans (An) (panel 2) as well as Aspergillus fumigatus (Afu) CBCs (panel 3) (3.13–200 nM) to different DNA duplexes. Sequences were derived from either the A. nidulans cycA (A) or cccA promoter (B) or the A. fumigatus cccA regulatory element (C). Binding responses of the indicated CBC concentrations injected in duplicate (black lines) are overlaid with the best fit derived from a 1:1 interaction model, including a mass transport term (red lines). KD constants and half-lives of the complexes are provided for each panel. Affinities of the mutant CBC are decreased by a factor of about 140–1,300 depending on the target sequence.