Improved Resolution from Double Constant-Time Evolution of 3D and 4D Triple-Resonance Experiments

Triple-resonance NMR experiments are nearly essential for performing backbone assignments of proteins larger than 15 kDa. Our work extends the double constant-time (2CT) evolution scheme to triple-resonance 3D and 4D experiments. The modifications needed to accomplish 2CT evolution in triple resonance experiments are straight forward, are completely general, and consequently, will yield increased resolution for all out-and-back experiments. We expect that the increased resolution of experiments presented here will be useful in the study of larger proteins (>30 kDa) and in the study of highly helical proteins where¹HN,¹⁵N, and¹³C dimensions are poorly dispersed.