Supplementary Figure 3: Sensitivity-enhanced (SE) and non-SE out-and-back 13C-19F TROSYs exhibit comparable sensitivity. | Nature Methods

Supplementary Figure 3: Sensitivity-enhanced (SE) and non-SE out-and-back 13C-19F TROSYs exhibit comparable sensitivity.

From: Aromatic 19F-13C TROSY: a background-free approach to probe biomolecular structure, function, and dynamics

Supplementary Figure 3

a,b, Pulse schemes for (a) SE and (b) non-SE TROSY versions. c,d, The TROSY spectra of 3-19F13C Tyr-labeled MBP recorded at 600 MHz with SE (c) and non-SE (d) pulse sequences show no substantial difference in sensitivity. Owing to the fast-relaxing 19F magnetization spending more time in the transverse plane in the SE version of the pulse sequence, the typical sensitivity gains associated with the SE experiment were offset. All narrow rectangles denote 90° pulses, and broad rectangles represent 180° pulses. 1H refocusing and decoupling were not possible because of the architecture of the probe, but could in principle be implemented and hence are represented in the pulse sequence. The duration of the delay T was set to 2.08 ms (= 1/2 JCF). Δ is a delay to refocus any chemical shift evolution occurring during evolution of the first point in the indirect dimension, whereas Δ1 refocuses chemical shift evolution occurring during the last gradient and the gradient recovery period. All pulses, unless otherwise noted, are applied along the x-axis. The phase cycles used are indicated under the respective pulse programs. The quadrature detection in the indirect dimension for a was achieved using the Echo-Anti-echo detection scheme, and for b it was done using the States-TPPI approach by incrementing the phase ϕ1. The duration and strengths of the gradients are g0 = (the length of the indirect encoding period, 1.65 Gauss/cm); g1 = (750 μs, 16.5 Gauss/cm); g2 = (500 μs, 44 Gauss/cm); g3 = (750 μs, 24.75 Gauss/cm); g4 = (750 μs, 27.5 Gauss/cm) and g5 = (500 μs, 23.51 Gauss/cm) in the SE version of the experiment (a). The duration and strengths of the gradients in the non-SE TROSY experiments (b) were g0 = (the length of the indirect encoding period, 1.65 Gauss/cm); g1 = (700 ms, 12.9 Gauss/cm); g2 = (500 ms, –33.0 Gauss/cm); g3 = (700 ms, 22 Gauss/cm); g4 = (700 ms, 31.68 Gauss/cm) and g5 = (500 ms, 23.52 Gauss/cm).

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