Lipid Bilayer Composition Affects Transmembrane Protein Orientation and Function

Figure 5

Orientation of Na⁺ K⁺-ATPase in proteoliposomes measured by the sidedness assay (𝑛=3). Proteoliposomes were created by nitrogen filtration, incubated ± ouabain ± detergent and then function (PO₄ production from ATP) was measured and used to calculate sidedness [33] to determine the relative amount of Na⁺ K⁺-ATPase that was facing inside out, right side out, or was not incorporated. All three orientations of enzyme were statistically different from each other (𝑃<.05).