Table 1.

Alignment of hydrophobic pocket residues for select GPCRs.

GPCR	ECL2-TM5 Sequence*
	45.52	5.35	5.36	5.37	5.38	5.39	5.40
D1R	Ser	Ser	Arg	Thr	Tyr	Ala	Ile
D2R	Ile	Asn	Pro	Ala	Phe	Val	Val
D3R	Ile	Asn	Pro	Asp	Phe	Val	Ile
D4R	Leu	Asp	Arg	Asp	Tyr	Val	Val
D5R	Ser	Asn	Arg	Thr	Tyr	Ala	Ile
5-HT1AR	Ile	Asp	His	Gly	Tyr	Thr	Ile
5-HT1BR	Val	His	Ile	Lys	Tyr	Thr	Val
5-HT2AR	Leu	Asp	Asp	Asn	Phe	Val	Leu
5-HT2BR	Leu	Phe	Gly	Asp	Phe	Met	Leu
5-HT2CR	Leu	Asp	Pro	Asn	Phe	Val	Leu
⍺1A	Ile	Glu	Pro	Gly	Tyr	Val	Leu
⍺1B	Val	Glu	Pro	Phe	Tyr	Ala	Leu
⍺1D	Ile	Glu	Ala	Gly	Tyr	Ala	Val
⍺2A	Ile	Gln	Lys	Trp	Tyr	Val	Ile
⍺2B	Leu	Glu	Ala	Trp	Tyr	Ile	Leu
⍺2C	Leu	Glu	Thr	Trp	Tyr	Ile	Leu
β1R	Phe	Gln	Arg	Ala	Tyr	Ala	Ile
β2R	Phe	Gln	Gln	Ala	Tyr	Ala	Ile
β3R	Phe	Gln	Met	Pro	Tyr	Val	Leu
V2R	Ala	Arg	Arg	Thr	Tyr	Val	Thr

^*Amino acid positions in transmembrane (TM) regions are delineated using Ballesteros and Weinstein nomenclature (29). The amino acid position in extracellular loop 2 (EL2) is delineated using the nomenclature developed by de Graaf et al. (77). Yellow indicates nonpolar amino acids with an aliphatic group (Ala, Val, Ile, Leu, Met, Gly); light green indicates hydrophobic amino acids with an aromatic ring (Phe, Tyr); dark green indicates Trp; purple indicates polar amino acids with an uncharged side chain (Ser, Thr, Asn, Gln); light grey indicates Pro; red indicates negatively charged amino acids (Glu, Asp); blue indicates positively charged amino acids (Arg, His, Lys).