Temperature dependence of proton–proton residual dipolar couplings in adenosine dissolved in charged phospholipid bicelles. Application of a two‐dimensional selective refocusing method

¹H NMR spectra of nucleoside adenosine were recorded in 7.5% (w/v) DMPC/DHPC bicelles doped with CTAB. Despite the small size of adenosine in comparison with the distances between discoidal bicelles, intramolecular ¹H,¹H residual dipolar couplings D were observed at 29.5–38°C. The absolute values of ¹H,¹H spin interactions Δ (sum of J‐ and D‐couplings) were measured selectively by a series of 2D SERF experiments as a function of temperature. At lower temperatures dipolar couplings are scaled down, which leads to simplification of the ¹H NMR spectra. For some pairs of protons, which are simultaneously J‐ and D‐coupled, the exact values of D can be determined from temperature dependence of Δ. Copyright © 2002 John Wiley & Sons, Ltd.