Figure 6.
Representative imino-proton exchange by solvent magnetization transfer and exchange catalystsis by ammonia. (a) Representative time courses of solvent magnitzation transfer to imino site of Guanine 6 in CGX-12 and CG-12 duplexes (240 mM [NH3] catalyst concentration). Solid line is the best fit of the data to eq 1. (b) Amonia concentration dependence of immino proton exchange for the indicated residues. Fitted parameters are listed in Table 3. (c) Summary of the effects of the CG-12 cross-link on imino proton exchange. Relative differences in base pair dynamics in CG-12 and CGX-12 are proportional to letter size. Letters in blue show decreased opening relative to CG-12, bases in green show no change, bases in black are exchanging too rapidly for measurement, and bases in grey to not have imino protons (cytosine and adenine).