Table 3.

¹³C T₂ relaxation times for different samples measured using a rotor-synchronized Hahn-echo sequence. 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, except the control sample which did not contain AMUPol. The peptide-containing samples, indicated as KL4/Lipids or Control, had KL₄ labeled with a single ¹³C isotope at the carbonyl position in L12 and peptides were reconstituted at 2 mol% relative to the lipids. Relaxation times for DNP samples are based on fitting data to multiple (>10) time points and are reported with 95% CI. For the control sample lacking biradical, only three time points were collected due to signal limitations.

Sample	Buffer	Lipid Glycerol	Lipid C=O	Lipid CH2	Peptide C=O
KL4/Lipids	15 ± 4 ms	4.9 ± 0.3 ms	33 ± 3 ms	8.0 ± 0.7 ms	37.1 ± 1.5 ms
Lipids only	9.9 ± 0.9	4.3 ± 0.2	35 ± 2	6.9 ± 0.5	--
Control	82 ± 20	3.2 ± 0.9	73 ± 5	11 ± 4	64 ± 18