Figure 3.

PRE effects induced by membrane-associated and free soluble spin labels on nanodisc-bound MC-KRAS-GTPγS alone and in the presence of FP-KRAS-GTPγS. The I_para/I_dia values of ILV ¹³C-methyls and Lys ¹⁵N-amides of MC-KRAS-GTPγS were measured with nanodiscs containing 5% Gd³⁺- or Cu²⁺-chelated PE-DTPA lipids (as indicated), or with 2 mM Gd-DTPA-BMA in solution, with Lu³⁺ serving as the diamagnetic control. NMR probes that exhibit increased or decreased PRE upon addition of FP-KRAS-GTPγS are color-coded red or blue, respectively, according to changes in ¹H transverse PRE rates of MC-KRAS-GTPγS (see Supporting Figure S7 and S9).