. Author manuscript; available in PMC: 2020 Jun 1.

Published in final edited form as: Prog Nucl Magn Reson Spectrosc. 2019 May 11;112-113:55–102. doi: 10.1016/j.pnmrs.2019.05.002

Table 1. Optimal settings for 1D off-resonance R_1ρ experiments using the pulse sequences shown in Fig. 21A.

Parameter	Optimal Value
ω_CP/2π^a	85 Hz^{b, c}
τ_CP	~1/4 \|¹JAH\|^d, ~3/4 \|¹JAH\|^e
Τ_eq	~3/k_ex
ω₁/2π^f	G-N1/U-N3	> ~50 Hz
	A-C8/G-C8	> ~45 Hz
	A-C2	> ~40 Hz
	C1′/C3′/C4′	> ~150 Hz
	C-C6/C-C5/U-C6/U-C5/T-C6	> ~200 Hz
	A-NH2/G-NH2/C-NH2	> ~70 Hz
ω_1H/2π	~10 kHz for ¹³C and ~5 – 8 kHz for ¹⁵N^g
ζ	π/2δ^h

(ω_CP/2π) >3^½/4 |¹J_AH|, A = ¹³C/¹⁵N

R_1ρ(¹⁵N) measurements on imino ¹⁵N (N1/N3). In theory, ω_CP/2π should be chosen to be equal to 3^½J_IS/4, the smallest value that can lead to complete magnetization transfer between spins, while also being selective and less sensitive to RF field inhomogeneities and mismatches in the Hartmann-Hahn matching condition[216]. However, in practice, a value of ω_CP/2π (= 85 Hz) larger than 3^½J_IS/4 ~ 39 Hz is typically employed so as to minimize losses of the magnetization due to conformational exchange[163].

R_1ρ(¹³C) measurements on aromatic and sugar ¹³C nuclei (C2/C5/C6/C8/C1′/C3′/C4′)

For AX (e.g. N1–H1 and C8–H8) and non-equivalent AX₂ (e.g. amino NH₂ group in WatsonCrick G-C BPs) spin systems[161, 217]

For equivalent AX₂ spin systems (e.g. amino NH₂ group in G-T/U wobbles)[161].

Should be greater than 3 times ²J_NN or ¹J_CC[21, 28]. The largest value that can be used depends on probe hardware limitations.

Should be > ω_eff(max)

δ is the offset in Hz of the undesired resonance in the ¹³C/¹⁵N dimension from the resonance of interest

Table 1. Optimal settings for 1D off-resonance R1ρ experiments using the pulse sequences shown in Fig. 21A.

Table 1. Optimal settings for 1D off-resonance R_1ρ experiments using the pulse sequences shown in Fig. 21A.