Figure 7.

Potential binding models for the complex between MGB-BP-3 and DNA. Model I—two symmetrical DNA complexes coexist within the same sample and exchange their identities through ligand rearrangement. Model II—An asymmetric DNA complex in which the original symmetry of the free DNA duplex is lifted through ligand binding in a manner that confers different identities on each DNA strand within the duplex. In both cases, slow chemical exchange on the NMR chemical shift timescale is identified through an extensive set of chemical exchange cross-peaks within the NMR data.