Restraints on backbone conformations in solid state NMR studies of uniformly labeled proteins from quantitative amide 15N-15N and carbonyl 13C-13C dipolar recoupling data

► 15N and 13C backbone recoupling (BARE) yields accurate dipolar dephasing curves. ► Torsion angle restraints detected through 2D NCACX, NCOCX, or COCA crosspeaks. ► 15N- and 13C-BARE restraints incorporated as 3D potential surfaces in Xplor-NIH. ► 15N-BARE and 13C-BARE restraints improve structural precision and accuracy.