Figure 18.

Changes in R₂ + R_ex as a function of k_ex and p_ES for two-state exchange during an off-resonance R_1ρ experiment, simulated using the B-M equations. Horizontal comparisons show changes in k_ex while vertical comparisons show changes in p_ES. Spin-lock amplitudes are denoted using different colors. Solid gray vertical lines correspond to an offset of –Δω, while the yellow star denotes exchange parameters typical of Watson-Crick to Hoogsteen exchange in B-DNA[115]. Other exchange parameters used are: $\Delta \overline{\omega }{(}^{13}\text{C)}=3\text{\hspace{0.17em}ppm}$, γ(¹H)B₀/2π = 700 MHz, R_1,GS = R_1,ES = 2.5 s ⁻¹ and R_2,GS = R_2,ES =22.5 s⁻¹. The initial alignment of the magnetization was performed as described in Section 6.1.