Residues of the stTrpA/stTrpB complex possessing highest conz ( k ) - values. For stTrpA (light blue) and stTrpB (gold), residues with conz(k)-values ≥ 2.0 and p-values ≤ 10-11 are plotted in red as sticks. H2rs predicted for stTrpA 2, and for stTrpB 13 important residue positions. Ligands indole-3-glycerol phosphate and pyridoxal phosphate are plotted as green sticks. The sodium ion is shown as a green ball.