Multiple Roles of the Extracellular Vestibule Amino Acid Residues in the Function of the Rat P2X4 Receptor
Figure 5
The effect of hydrophobicity and the size at position 324 on ATP potency and the localization of the F324 and G325 residues in the rP2X4R molecule.
(A and B) The correlation between the EC50 values with the hydrophobic effect (A) and the change in side chain residue volume (B). (C) Both the F324 and G325 residues are within the β-sheet (in green) connecting the ATP binding site and the pore in the zfP2X4 apo-closed state (left) and outside the β-sheet in the ATP-bound open state (right); rP2X4 numbering. Notice the stable position of Y54 and Q55, and conserved protein fold above TM1 (arrowhead) both in the closed and open state.