Table 2

Other GPCR helix-helix interactions found experimentally.

Residue Indices	Receptors	Experimental Methods		Residues/Mutations	Cβ-Cβ	References
Residue Indices	Receptors	C	R	Residues/Mutations	Cβ-Cβ	References	Z
1.39 7.36	ACM2-ACM5		⁺		T37A H423T	11.8	Liu et al., 1995
2.50 7.49	GRHR		⁺		N87D D318N	7.0	Zhou et al., 1994
2.50 7.49	5H2A		⁺		D120N N376D	7.0	Sealfon et al., 1995
2.64 3.28	NK1R			⁺	Y92H H108	6.6	Elling and Schwartz, 1996
3.29 5.35	NK1R			⁺	N109H E193H	14.0	Elling and Schwartz, 1996
3.32 7.39	B2AR			⁺	D113H N312C	15.5^2-a	Elling et al., 1999
3.43 6.44	ACM1			⁺	L116H F374H	6.3	Lu and Hulme, 2000
3.43 7.49	ACM1			⁺	L116H N414H	10.1	Lu and Hulme, 2000
3.53 6.30	B2AR			⁺	A134H E268H	6.1	Sheikh et al., 1999
3.53 6.31	B2AR			⁺	A134H H269	10.7	Sheikh et al., 1999
3.53 6.34	B2AR			⁺	A134H L272H	8.3	Sheikh et al., 1999
3.54 6.29	ACM2	⁺			I169C K484C	11.5	Zeng et al., 1999
3.54 6.30	ACM3	⁺			I169C E485C	6.3	Zeng et al., 1999
3.54 6.31	ACM3	⁺			I169C K486C	8.2	Zeng et al., 1999
3.54 6.32	ACM3	⁺			I169C K487C	11.8	Zeng et al., 1999
3.54 6.33	ACM3	⁺			I169C A488C	8.9	Zeng et al., 1999
3.54 6.34	ACM3	⁺			I169C A489C	5.7	Zeng et al., 1999
3.54 6.35	ACM3	⁺			I169C Q490C	10.8	Zeng et al., 1999
3.54 6.36	ACM3	⁺			I169C T491C	12.4	Zeng et al., 1999
5.35 6.59	NK1R			⁺	E193H Y272H	9.0	Elling et al., 1995
5.39 6.55	NK1R			⁺	H197 F268H	8.6	Elling et al., 1995
5.39 6.56	NK1R			⁺	H197 L269H	8.5	Elling et al., 1995
5.39 6.59	NK1R			⁺	H197 Y272H	5.1	Elling et al., 1995
6.44 7.49	ACM1			⁺	F374H N414H	9.0	Lu and Hulme, 2000
TM1/TM2 7.39	B2AR-A2AA		⁺		N312F		Mizobe et al., 1996
TM3/TM6 7.38	B2AR-A2AA		⁺		L311F		Mizobe et al., 1996

Cβ-Cβ is the distance between the Cβ of two residues in bovine rhodopsin structure. Receptor names are abbreviated according to their SWISS-PROT Annotated Protein Sequence Database entry names:http://www.expasy.ch/cgi-bin/lists?7tmrlist.txt

C, Cys-Cys crosslinking; R, double revertant mutations; Z, Zinc-His binding; E, spin-labeling; L, ligand related; F, Fourier-transform infrared difference spectroscopy.
↵2-a Present only in the active state.