27EM: Beta-arrestin-1

Cryo_EM structure of PACAP27_PAC1R_Beta_arrestin 1 complex. Determined by electron microscopy at 3.0 Å resolution. Released 16 Sept 2026.

Method: Electron microscopy
Resolution: 3.0 Å
Organisms: Homo sapiens, synthetic construct
Chains: 5
Atoms: 9,095
Mol. weight: 146.51 kDa
Released: 16 Sept 2026

Explore 27EM in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

27EM contains 41 α-helices and 76 β-strands across 5 chains. Residue ranges use author residue numbering, as in the PDB file, from PDBe. To see them in 3D, choose the Cartoon representation with Secondary structure coloring: helices, sheets and coils get different colors.

Chain B: 12 helices, 28 β-strands

Element	Residues	Length	Sheet
β-strand	9-12	4	1
β-strand	18-22	5	1
β-strand	26-28	3	2
β-strand	29	1	3
β-strand	34	1	3
β-strand	37-43	7	1
α-helix	45-47	3
β-strand	52-62	11	4
β-strand	76-85	10	4
α-helix	96-98	3
α-helix	99-108	10
β-strand	112-117	6	1
α-helix	119-120	2
α-helix	123-125	3
β-strand	127-129	3	5
α-helix	130-131	2
α-helix	138-140	3
β-strand	141	1	5
β-strand	142-151	10	4
α-helix	157-158	2
β-strand	163-168	6	4
β-strand	169-171	3	2
α-helix	180-182	3
β-strand	183-188	6	6
β-strand	197-203	7	6
β-strand	207-208	2	7
β-strand	214-222	9	6
β-strand	228	1	8
β-strand	230-241	12	9
β-strand	247-258	12	9
β-strand	262	1	8
β-strand	266-274	9	6
α-helix	279-281	3
β-strand	288-290	3	5
β-strand	300	1	5
α-helix	301-304	4
β-strand	317-328	12	9
β-strand	343-349	7	9
β-strand	350-351	2	7
α-helix	353-356	4

Chain C: 4 helices, 21 β-strands

Element	Residues	Length	Sheet
β-strand	6-10	5	10
β-strand	14-15	2	11
β-strand	21-28	8	10
β-strand	35-42	8	12
β-strand	48-55	8	12
β-strand	60-63	4	12
β-strand	72-76	5	10
β-strand	81-86	6	10
α-helix	91-93	3
β-strand	95-97	3	13
β-strand	98-103	6	12
β-strand	112-113	2	12
α-helix	114-116	3
β-strand	117-119	3	13
β-strand	120-121	2	11
β-strand	130-133	4	14
β-strand	146-155	10	14
β-strand	161-164	4	15
α-helix	165-167	3
β-strand	173-175	3	14
α-helix	176-178	3
β-strand	179	1	14
β-strand	186-194	9	14
β-strand	206-210	5	15
β-strand	215-218	4	15

Chain E: 7 helices, 18 β-strands

Element	Residues	Length	Sheet
β-strand	5-7	3	16
β-strand	11-14	4	17
β-strand	21-26	6	16
β-strand	34-39	6	17
β-strand	46-50	5	17
β-strand	54-55	2	17
α-helix	56	1
β-strand	64-67	4	16
β-strand	72-75	4	16
α-helix	81-83	3
β-strand	86-91	6	17
β-strand	98-99	2	17
β-strand	103-107	5	17
α-helix	113-116	4
β-strand	117-119	3	18
α-helix	120-122	3
α-helix	123-127	5
β-strand	130-140	11	18
β-strand	147-151	5	19
β-strand	160-165	6	18
α-helix	166-168	3
β-strand	174-183	10	18
α-helix	184-189	6
β-strand	192-197	6	19
β-strand	206-211	6	19

Chain P: 1 helix, 0 β-strands

Element	Residues	Length	Sheet
α-helix	2-26	25

Chain R: 17 helices, 9 β-strands

Element	Residues	Length	Sheet
α-helix	26-45	20
β-strand	53-54	2	20
β-strand	57-58	2	21
β-strand	63-64	2	21
β-strand	67-68	2	20
β-strand	71-76	6	22
α-helix	77-78	2
α-helix	79-83	5
β-strand	113-118	6	22
β-strand	123	1	22
α-helix	124-126	3
β-strand	127	1	22
α-helix	130-133	4
α-helix	142-176	35
α-helix	184-207	24
α-helix	208-212	5
α-helix	224-256	33
α-helix	262-290	29
α-helix	303-335	33
α-helix	343-362	20
α-helix	364-369	6
α-helix	380-391	12
α-helix	393-397	5
α-helix	398-402	5
α-helix	411-414	4
β-strand	435-436	2	1

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Beta-arrestin-1	B	protein	391	Homo sapiens	P49407 (AlphaFold model)
Fab30H	C	protein	230	synthetic construct
Fab30L	E	protein	215	synthetic construct
Pituitary adenylate cyclase-activating polypeptide 27	P	protein	28	Homo sapiens	P18509 (AlphaFold model)
Pituitary adenylate cyclase-activating polypeptide type I receptor	R	protein	443	Homo sapiens	P41586 (AlphaFold model)

Sequence of entity 1 (B), FASTA

>27EM_1 Beta-arrestin-1 (chains B)
MKGTRVFKKASPNGKLTVYLGKRDFVDHIDLVDPVDGVVLVDPEYLKERRVYVTLTCAFR
YGREDLDVLGLTFRKDLFVANVQSFPPAPEDKKPLTRLQERLIKKLGEHAYPFTFEIPPN
LPCSVTLQPGPEDTGKACGVDYEVKAFCAENLEEKIHKRNSVRLVIRKVQYAPERPGPQP
TAETTRQFLMSDKPLHLEASLDKEIYYHGEPISVNVHVTNNTNKTVKKIKISVRQYADIC
LFNTAQYKCPVAMEEADDTVAPSSTFCKVYTLTPFLCNNREKRGLALDGKLKHEDTNLAS
STLLREGANREILGIIVSYKVKVKLVVSRGGLLGDLASSDVAVELPFTLMHPKPKEEPPH
REVPENETPVDTNLIELDTNDDDAAAEDFAR

Sequence of entity 2 (C), FASTA

>27EM_2 Fab30H (chains C)
MEISEVQLVESGGGLVQPGGSLRLSCAASGFNVYSSSIHWVRQAPGKGLEWVASISSYYC
YTYYADSVKGRFTISADTSKNTAYLQMNSLRAEDTAVYYCARSRQFWYSGLDYWGQGTLV
TVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAV
LQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKT

Sequence of entity 3 (E), FASTA

>27EM_3 Fab30L (chains E)
SDIQMTQSPSSLSASVGDRVTITCRASQSVSSAVAWYQQKPGKAPKLLIYSASSLYSGVP
SRFSGSRSGTDFTLTISSLQPEDFATYYCQQYKYVPVTFGQGTKVEIKRTVAAPSVFIFP
PSDSQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTL
TLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC

Sequence of entity 4 (P), FASTA

>27EM_4 Pituitary adenylate cyclase-activating polypeptide 27 (chains P)
HSDGIFTDSYSRYRKQMAVKKYLAAVLX

Sequence of entity 5 (R), FASTA

>27EM_5 Pituitary adenylate cyclase-activating polypeptide type I receptor (chains R)
MHSDCIFKKEQAMCLEKIQRANELMGFNDSSPGCPGMWDNITCWKPAHVGEMVLVSCPEL
FRIFNPDQVWETETIGESDFGDSNSLDLSDMGVVSRNCTEDGWSEPFPHYFDACGFDEYE
SETGDQDYYYLSVKALYTVGYSTSLVTLTTAMVILCRFRKLHCTRNFIHMNLFVSFMLRA
ISVFIKDWILYAEQDSNHCFISTVECKAVMVFFHYCVVSNYFWLFIEGLYLFTLLVETFF
PERRYFYWYTIIGWGTPTVCVTVWATLRLYFDDTGCWDMNDSTALWWVIKGPVVGSIMVN
FVLFIGIIVILVQKLQSPDMGGNESSIYLRLARSTLLLIPLFGIHYTVFAFSPENVSKRE
RLVFELGLGSFQGFVVAVLYCFLNGEVQAEIKRKWRSWKVNRYFAVDFKHRHPSARGRTP
PSLGPQDESCTTASSSLAKDTSS

Primary citation

Structural basis of beta-arrestin coupling and transducer selectivity in PAC1R. Zhang, M., Li, X., Yuan, Q.N. et al. Acta Pharmacol Sin (2026). DOI 10.1038/s41401-026-01924-4 · PubMed

Other PDB entries of the same protein (UniProt P49407 (AlphaFold model), which also has an AlphaFold model), best resolution first:

8AS4 2.3 Å, Crystal structure of human beta-arrestin-1
9ZZO 2.6 Å, MP1104-bound Kappa Opioid Receptor in complex with beta-arrestin1
8ZYT 2.65 Å, Cryo-EM structure of neurotensin receptor 1 in complex with beta-arrestin1 and SBI-553…
8ZYU 2.65 Å, Cryo-EM structure of neurotensin receptor 1 in complex with beta-arrestin1 and SBI-553…
2IV8 2.8 Å, beta appendage in complex with b-arrestin peptide
8ZYY 2.83 Å, Cryo-EM structure of neurotensin receptor 1 in complex with beta-arrestin1 and SBI-553…
9UYN 2.9 Å, Cryo-EM structure of the G protein-coupled receptor 1 (GPR1) bound to beta-arrestin 1 in…
9LXR 3.07 Å, A Cryo-EM structure of LA-PTH-PTH1R-Beta-arrestin1 complex (state 1 conformation)
9LY2 3.1 Å, A Cryo-EM structure of LA-PTH-PTH1R-V2RT-Beta-arrestin1 complex (state 1 conformation)
9MBA 3.14 Å, Cryo-EM structure of complex of transducer-bound GPCR
25GN 3.2 Å, receptor-arrestin
8AS2 3.2 Å, Structure of arrestin2 in complex with 4P CCR5 phosphopeptide and Fab30

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