Fig. 6.

Intensity build-up in the aromatic {¹H}–¹³C NOE experiment. a Difference intensity (saturation experiment − reference experiment) of the {¹H}–¹³C NOE experiment shown as a function of ¹H saturation time for the pulse sequences that correspond to the L-optimized (black circles) and non-L-optimized (grey squares) versions, using a constant pre-saturation delay of 4 s. b Difference intensity as a function of pre-saturation delays using a ¹H saturation time of 2 s. c Intensity originating from ¹³C excitation (reference experiment) as a function of the recovery delay. Optimal delays are indicated with black arrows: the ¹H saturation period is 2 s, and the pre-saturation delay is 1.3 s. The resulting recovery delay of 3.3 s equals approximately 6/R ₁, ensuring that the ¹³C magnetization has completely returned to equilibrium. The data represent the summed intensity of four residues: Phe149 Cδ* + Phe159 Cδ* + Tyr118 Cδ* + Tyr221 Cδ*