Figure 2.

(A) Exonuclease III footprints of the 1–477 σ^N protein and 180–477, 306–477 (non-His and His-tagged), and 329–477 peptides each at 250 mM and 1 μM. On the basis of the intensity of the block at −33 the σ^N and 180–477 peptides displayed stronger binding than the 306–477 and 329–477 peptides. (B) Increase of the −33 exonuclease III footprint signal in a combined DNA-binding assay. The presence of 1 μM 70–324 peptide combined with the 329–477 peptide (25 nM, 50 nM, 100 nM, 250 nM, 500 nM, and 1 μM) produced a significantly stronger footprint signal compared with single protein footprints (1 μM). The 70–324 peptide was added to the assay mix prior to the 329–477 peptide. (C) Combined exonuclease III footprint with the 329–477 peptide (+) at 250 nM and a series of peptides (70–184, 70–215, 70–268, 70–324) at 1 μM. Peptides were premixed (20–25 μM) before addition of the DNA.