Figure 4.

(A) The three primer-template constructs used to measure spectral perturbations in PaePE: D18p contains a 3′-phosphate; D16F1R1, contains a 2′-fluorocytidine (to closely mimic a ribose) in the penultimate position and a 3′-terminal ribocytidine. (B) Results of the NMR titration of PaePE with D18. ¹⁵N,¹H TROSY spectra acquired at 600 MHz in the absence (red) and the presence of equimolar amounts of D18 (blue). The inset shows the trajectory of the resonance corresponding to Leu157 that lies on β8 during the course of the titration.