Facile measurement of ¹H-¹5N residual dipolar couplings in larger perdeuterated proteins.

We present a simple method, ARTSY, for extracting ¹J(NH) couplings and ¹H-¹⁵N RDCs from an interleaved set of two-dimensional ¹H-¹⁵N TROSY-HSQC spectra, based on the principle of quantitative J correlation. The primary advantage of the ARTSY method over other methods is the ability to measure couplings without scaling peak positions or altering the narrow line widths characteristic of TROSY spectra. Accuracy of the method is demonstrated for the model system GB3. Application to the catalytic core domain of HIV integrase, a 36 kDa homodimer with unfavorable spectral characteristics, demonstrates its practical utility. Precision of the RDC measurement is limited by the signal-to-noise ratio, S/N, achievable in the 2D TROSY-HSQC spectrum, and is approximately given by 30/(S/N) Hz.