The two other subunits (shown in yellow, and orange in the background) are in the IFS. The transporter is in substrate-loaded state (all subunits have a bound aspartate, shown in red space-filling). Each subunit also has two bound sodium ions (blue spheres). Residues I61, S65, Y195, M286 and P304 are shown green, yellow, pink, orange, and tan space-filling representations, in the reconfiguring subunit. M286 (orange) and P304 (tan) get away from S65 and Y195, to induce an opening in the IC-facing end of the cavity, although the putative channeling pore remains closed in the iOFS.