Lipid Bilayer Composition Affects Transmembrane Protein Orientation and Function

Figure 6

Orientation of Na⁺ K⁺-ATPase in HPM alone and in HPM: SL proteoliposomes measured by the sidedness assay. Proteoliposomes were created by nitrogen filtration using HPM or HPM: SL lipids (1 : 1; wt : wt), 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. Differences between HPM proteoliposomes and HPM: SL proteoliposomes are indicated by ∗.