Table 1. Putative GABA_B2 allosteric binding site.

SIFt(8), SIFt(7) profiles and corresponding amino acids in GABA_B2 subunit and mGlu1 and mGlu5 receptors. GPCRdb(C), GPCR database numbering. Amino acids in bold have been shown to change binding/potency of allosteric ligands > 5-fold when mutated in other class C human receptors (data extracted from GPCRdb [5,6] accessed Nov. 25, 2015).

GPCRdb(C)	GABAB2	mGlu1	mGlu5	SIFt(8)	SIFt(7)
3.33x33	T557	R661	R648	0.67	0.74
3.36x36	L560	V664	I651	1	1
3.37x37	T561	G665	G652	0.7	0.67
3.40x40	Y564	S668	P655	1	1
3.41x41	T565	A669	A656	0.62	0.58
3.44x44	F568	Y672	Y659	0.71	0.79
5.39x39	W656	G752	G739	0.6	0.56
5.40x40	L657	V753	V740	0.9	1
5.43x43	V660	P756	P743	0.63	0.68
5.44x44	Y661	L757	L744	0.9	1
5.47x47	K664	N760	N747	0.99	1
5.48x48	G665	G761	G748	0.57	0.63
5.50x50	L667	L763	L750	0.46	0.52
5.51x51	M668	I764	I751	0.75	0.83
6.46x46	V699	T794	T781	0.9	1
6.49x49	M702	I797	I784	1	1
6.50x50	C703	W798	W785	1	1
6.53x53	G706	F801	F788	0.97	0.96
6.54x54	A707	V802	V789	0.9	0.88
6.57x57	S710	Y805	Y792	1	1
7.31x32	I723	T814	T801	0.68	0.75
7.32x33	V724	T815	M802	1	1
7.35x36	V727	A818	S805	0.9	1
7.36x37	I728	V819	V806	0.69	0.65
7.39x40	C731	S822	S809	0.98	1