Figure 2. In silico modeling of V-9302 interactions with human ASCT2 (hASCT2).

(A) Homology model of hASCT2 (trimer shown) with V-9302 docked into the orthosteric binding site within the transmembrane region of the protein (extracellular membrane - red plane; intracellular membrane - blue plane). (B) Expanded view of residues proximal to V-9302 within the orthosteric binding site. Top scoring pose shown. (C) Overlay of V-9302 and ASCT2 substrate, glutamine, docked into the orthosteric binding site. (D) In silico alanine scan of the hASCT2 binding pocket. Positive values indicate alanine substitution interacts less favorably with V-9302 relative to the native residue. The total interface score is a weighted summation of the hydrogen bonding scores, repulsion penalties, solvation energies, and electrostatic potential. Glutamine and V-9302 were evaluated in a homology model of LAT1. (E) Ligand interaction diagram of glutamine or V-9302 in LAT1 visualized in the MOE molecular modeling and simulation package. Steric clash with the surrounding residues indicated in red (only seen with V-9302). (F) Docking scores for glutamine and V-9302 into LAT1; similar fit observed for glutamine in LAT1 and ASCT2, while V-9302 only fits the ASCT2 binding pocket. n = 100 top scoring poses per condition. P values determined by Student’s t test. For box plots, center line is plotted at the median; the box spans from the first quartile to the third quartile; whiskers represent min to max.