A compact high-speed mechanical sample shuttle for field-dependent high-resolution solution NMR

Analysis of NMR relaxation data has provided significant insight on molecular dynamic, leading to a more comprehensive understanding of macromolecular functions. However, traditional methodology allows relaxation measurements performed only at a few fixed high fields, thus severely restricting their potential for extracting more complete dynamic information. Here we report the design and performance of a compact high-speed servo-mechanical shuttle assembly adapted to a commercial 600 MHz high-field superconducting magnet. The assembly is capable of shuttling the sample in a regular NMR tube from the center of the magnet to the top (fringe field similar to 0.01 T) in 100 ms with no loss of sensitivity other than that due to intrinsic relaxation. The shuttle device can be installed by a single experienced user in 30 min. Excellent 2D-N-15-HSQC spectra of (u-C-13, N-15)-ubiquitin with relaxation at low fields (3.77 T) and detection at 14.1 T were obtained to illustrate its utility in R-1 measurements of macromolecules at low fields. Field-dependent C-13-R-1 data of (3,3,3-d)-alanine at various field strengths were determined and analyzed to assess CSA and H-1-C-13 dipolar contributions to the carboxyl C-13-R-1. (C) 2011 Elsevier Inc. All rights reserved.