TABLE 4.

Contacts of α-conotoxin RegIIA with hα3β2 and hα3β4 nAChR, respectively

Contacts between nAChR and RegIIA are defined as van der Waals interactions if the distance between heavy atoms of RegIIA and nAChR is between 2.6 and 4 Å. Residues of the nAChR forming hydrogen bonds with RegIIA are underlined. Residues that are non-conserved between α3β2 and α3β4 nAChRs, as well as RegIIA residues making contact with them are shown in bold.

Residuea	α3β2 nAChR		α3β4 nAChR
	+b	−c	+b	−c
Ser4		Asp171		Asp171
His5	Tyr93, Tyr190, Tyr197		Tyr93, Tyr190, Tyr197
Pro6	Tyr93, Trp149	Trp57	Tyr93, Trp149	Leu121
Ala7	Ser150, Tyr197		Ser150, Tyr197
Asn9		Trp57, Thr59, Phe119, Leu121		Lys59, Leu121
Val10	Ser150	Arg81, Val111, Phe119, Leu121	Ser150	Arg81, Ile111, Leu119, Leu121
Asn11	Asp152, Glu195, Tyr197	Lys79, Arg81, Val111	Asp152, Glu195, Tyr197	Ile79, Arg81, Ile111
Asn12	Cys192, Cys193, Glu195		Cys192, Cys193, Glu195
His14	Cys192, Cys193		Cys192, Cys193
Ile15	Cys192, Cys193		Cys192, Cys193

^a Only RegIIA residues making direct contact with the nAChRs are listed.

^b Residues of the principal side of the binding site.

^c Residues of the complementary side of the binding site.