Answer
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The five membrane-spanning α-helices of the transmembrane protein are likely arranged in a pentameric circle within the lipid bilayer. In this arrangement, the hydrophobic faces of each helix interact with the lipid tails, anchoring the protein in the membrane, while the hydrophilic faces of the helices point toward the center, forming a cylindrical pore. This central pore provides an aqueous pathway that allows Na⁺ ions to enter the cell when the channel is activated by ligand binding, combining both membrane stability and selective ion transport.
