Figure 3.

Alignment of the bovine rhodopsin, 5-HT_2A and D₂ receptor sequences. Sequence positions highlighted in red indicate highly conserved amino acids among the Class A GPCR family that serve as reference positions in the general Ballesteros-Weinstein¹¹⁰ numbering system. The traditional numbering is also given for the 5-HT_2A (top) and D₂ (bottom) sequences. Bovine rhodopsin residues highlighted in green indicate positions that are within 12.0 Å of bound retinal; these were mutated to alanine prior to the 3-D model building phase. Bovine rhodopsin residues highlighted in purple indicate positions in the third intracellular loop that were mutated to glycine in the 5-HT_2A sequence and in subsequent 5-HT_2A models. Residues highlighted in yellow boxes in the 5-HT_2A sequence represent those that are closest to AMDA (within 4.5 Å heavy atom to heavy atom) in the antagonist model. Note: The D₃, M₁, V_1a, β₂ and δ-opioid GPCR sequences have been omitted for brevity and clarity (see text for details). The figure was created using ALSCRIPT.¹¹¹