Fig. 1: Conformational states of the trimeric GltTk.
From: Structural ensemble of a glutamate transporter homologue in lipid nanodisc environment
a, b Volume and cartoon representation of five cryo-EM structures of GltTk in MSP2N2 nanodiscs obtained in the absence of substrate (Na+-only), in presence of L-aspartate (unsaturated 2in:1out, unsaturated 1in:2out, saturated) or in the presence of DL-TBOA. The approximate position of the lipid bilayer is represented by the light gray bar, with indication of sides of the membrane (in and out). a The cryo-EM density for the MSP2N2 belt is shown in dark gray. The transport domains of the individual protomers are present in four different conformations: inward open (steel blue), intermediate-outward occluded apo (cyan), intermediate-outward occluded Asp (cornflower blue), outward-open TBOA (dark blue). The scaffold domains are shown in yellow. c Table summarizing conformations of GltTk protomers. Schematic representation of the conformations on the right in the same colors as in a, b, with indication of l-aspartate (black circle), DL-TBOA (black square) and HP2 (dark red stick).
