Optimized pathway selection in intraresidual triple-resonance experiments

An optimized intraresidual pulse sequence element with better sensitivity and suppression of sequential cross peaks is presented. Concatenation of three magnetization transfer delays allows their independent setting, in accordance with the relaxation properties of the individual spins, without concomitantly prolonging the pulse sequence. Additionally, implementations of the scheme to HNCA, HNCACB, and the TROSY based triple-resonance experiments are proposed. The feasibility of the new element was verified by recording HNCA and HNCACB on the small 8.6kDa protein ubiquitin. The corresponding HNCA-TROSY experiment was tested on a larger protein, the 30.4kDa Ce16A from the thermophilic soil bacterium Thermobilida fusca at 800 H-1 MHz. (C) 2004 Elsevier Inc. All rights reserved.