2D and 3D TROSY-enhanced NOESY of ¹⁵N labeled proteins

Recently, several TROSY-based experiments have been designed for backbone chemical shift assignment and measurement of the NOEs of ²H, ¹³C and ¹⁵N labeled proteins. Here, we present TROSY-enhanced NOESY experiments, namely the 2D S3E-NOESY-S3E, 3D TROSY-NOESY-S3E and S3E-NOESY-TROSY experiments. These experiments use the spin-state selective excitation method (S3E), and have the TROSY effect in all the indirectly and directly detected dimensions, and so provide optimal resolution for amide protons. The first two experiments provide an additional useful feature in that the diagonal peaks of the amide proton region are cancelled or greatly reduced, allowing clear identification of NOE cross peaks that are close to diagonal peaks.