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.
Bibliographical noteFunding Information:
This work is supported by grants from the Research Grant Council of Hong Kong (HKUST6197/97M and HKUST6038/98M). We also thank Dr. Mingjie Zhang for providing the 15N labeled calmodulin, and Dr. D.K. Smith for critical discussions. The Hong Kong Biotechnology Research Institute is acknowledged for the purchase of the 750 MHz NMR spectrometer.
- N labeled proteins