Table 2.

Hydrogen bonds predicted by ChimeraX between receptor and peptide chains and receptor and G protein chains

Receptor - Peptide
PAC1R-PACAP27			VPAC1-PACAP27			VPAC1-VIP
Peptide	Receptor	Distance (Å)	Peptide	Receptor	Distance (Å)	Peptide	Receptor	Distance (Å)
D3	Y1.47	3.34	H1	Q3.37	2.65	H1	Q3.37	3.16
D3	Y1.47	3.36	S2	E7.42	3.29	S2	M7.39	3.37 (bb)
D3	R2.60	3.31 (s)	D3	Y1.47	3.36	D3	R2.60	2.87 (s)
D3	R2.60	2.55 (s)	D3	R2.60	2.94 (s)	T7	K2.67	2.46
T7	K2.67	2.50	T7	K2.67	2.51	N9	Y1.36	3.38
D8	N300ECL2	2.86	S11	D287ECL2	2.93	T11	D287ECL2	3.01
S11	Y2.72	3.18	R12	N290ECL2	2.99	L27	Y118ECD	2.35 (bb)
S11	D298ECL2	2.91	Y13	D1.29	3.20 (bb)
R12	D301ECL2	2.90 (s)	Y13	T1.33	2.77
Y22	N60ECD	3.27	K20	G123ECD	3.43 (bb)

Receptor – G proteins
PAC1R-PACAP27-Gs			VPAC1-PACAP27-Gs			VPAC1-VIP-Gs
Gs	Receptor	Distance (Å)	Gs	Receptor	Distance (Å)	Gs	Receptor	Distance (Å)
D381	K5.64	2.56	N384	L244ICL2	2.83	N384	L244ICL2	2.64
N384	L255ICL2	2.75	N384	K5.64	2.93	R385	K5.64	3.54 (bb)
N384	K5.64	2.87	R385	K5.64	3.27 (bb)	R380	S247	3.41
R385	K5.64	3.10 (bb)	R385	K5.64	3.48 (bb)	N384	K5.64	2.78
E392	G405H8	2.72	Y391	H1.50	3.20	D323	R329ICL3	3.08
L393	S6.41	3.16	E392	G393H8	2.91	E392	G393H8	2.82
			L393	S6.41	2.73

Gβ	Receptor	Distance (Å)	Gβ	Receptor	Distance (Å)	Gβ	Receptor	Distance (Å)
H311	R413H8	2.43	n/a			n/a
D312	R413H8	3.15

Hydrogen bonds were predicted using relaxed parameters and distances are shown in Å. (s) indicates a salt bridge. (bb) indicates interactions with the backbone. n/a: no hydrogen bonds present. Receptor residues are labelled according to the Wootten et al. numbering system.