Fig. 3.

Minor augmentations in membrane composition enable interrogation of lipid physical properties on NarX activity. (A) By altering 10 mol% of the lipid in vesicles composed of POPC, protein expression can be conserved and allow differences in activity to be attributed to protein–lipid interactions. (B) Western blot band intensity of NarX for all samples shows that protein expression was not substantially different when membrane composition was changed. (C) NarX activity and fold change in luminescence varied with membrane composition. Numbers above the bar graph indicate the fold change in luminescence upon the addition of nitrate relative to water. (D) Spearman’s correlation demonstrates that changes in luminescence and on/off ratio correlate with lipid physical properties. (E) Lipid critical packing parameter was found to linearly correlate with the fold change in luminescence upon the addition of nitrate relative to water. All error bars represent the SEM for n = 3 independent replicates.