Table 2.

DNP buildup times for different samples. All samples were comprised of 5.5/2.7/2/1 DPPC-d₆₂/DPPC/POPG/cholesterol lipids reconstituted in UB, pH 7.4, containing 10 mM AMUPol and 10% DMSO. Peptide-containing samples consisted of KL₄ with a single ¹³C isotope at the carbonyl position. Site-specific ¹³C labelled KL₄ peptides at residues L12 or L12,L13 were synthesized and peptides were reconstituted at 2 mol% relative to the lipids. Buildup times are based on fitting data to nine time points and are reported with 95% CI.

Sample	Buffer	Lipid Glycerol	Lipid C=O	Lipid CH2	Lipid C=C	Peptide C=O
KL4/Lipids-1	2.7 ± 0.7 s	2.2 ± 0.2 s	3.5 ± 0.3 s	3.3 ± 0.2 s	4.2 ± 0.7 s	3.6 ± 0.1 s
KL4/Lipids-2	1.4 ± 0.1	1.6 ± 0.1	2.3 ± 0.2	2.2 ± 0.1	2.0 ± 0.6	1.8 ± 0.1
Lipids only	3.2 ± 0.6	3.5 ± 0.4	8.8 ± 0.5	7.7 ± 0.2	8.1 ± 1.2	--