Fig. 4.

Overlay of the ¹H-¹⁵N HSQC spectra of AraC arm-dimerization domain, residues 2–166 in the presence of arabinose (red) and in the absence of arabinose (black). The contour level threshold has been adjusted to show only the more intense peaks. The stars and labels indicate the crosspeak positions of the AraC arm residues in free arm under identical solvent conditions. No cross-peaks were observed in these positions in either spectrum. The intense peaks that occur in pairs in the ¹⁵N 110–113 ppm region of the spectrum result from side chain amides.