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

Recently, several TROSY-based experiments have been designed for backbone c hemical shift assignment and measurement of the NOEs of H-2, C-13 and N-15 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 dimensio ns, and so provide optimal resolution for amide protons. The first two expe riments provide an additional useful feature in that the diagonal peaks of the amide proton region are cancelled or greatly reduced, allowing clear id entification of NOE cross peaks that are close to diagonal peaks.