23SO: Cebranopadol-mu opioid receptor-Gi complex

Cryo-EM structure of the cebranopadol-mu opioid receptor-Gi complex. Determined by electron microscopy at 2.95 Å resolution. Released 1 Jul 2026.

Method: Electron microscopy
Resolution: 2.95 Å
Organisms: Rattus norvegicus, Bos taurus, Homo sapiens
Chains: 7
Atoms: 11,705
Mol. weight: 246.9 kDa
Ligands: CLR, A1E5L
Released: 1 Jul 2026

Explore 23SO in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

23SO contains 54 α-helices and 65 β-strands across 7 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 A: 10 helices, 8 β-strands

Element	Residues	Length	Sheet
α-helix	7-31	25
β-strand	34-40	7	10
α-helix	46-54	9
β-strand	185-190	6	10
β-strand	195-200	6	10
α-helix	208-211	4
α-helix	212-215	4
β-strand	220-226	7	10
α-helix	227-229	3
β-strand	233	1	11
α-helix	234	1
β-strand	241	1	11
α-helix	242-254	13
β-strand	263-269	7	10
α-helix	271-280	10
α-helix	296-309	14
β-strand	319-323	5	10
α-helix	328-351	24

Chain B: 3 helices, 28 β-strands

Element	Residues	Length	Sheet
α-helix	6-25	20
α-helix	30-34	5
α-helix	38-39	2
β-strand	47-51	5	1
β-strand	58-63	6	2
β-strand	69-74	6	2
β-strand	78-83	6	2
β-strand	89-94	6	2
β-strand	100-105	6	3
β-strand	111-116	6	3
β-strand	120-125	6	3
β-strand	135-140	6	3
β-strand	146-151	6	4
β-strand	156-161	6	4
β-strand	165-170	6	4
β-strand	176-181	6	4
β-strand	189-192	4	5
β-strand	198-202	5	5
β-strand	208-212	5	5
β-strand	218-222	5	5
β-strand	231-234	4	6
β-strand	240-244	5	6
β-strand	249-254	6	6
β-strand	259-265	7	6
β-strand	273-278	6	7
β-strand	284-289	6	7
β-strand	293-298	6	7
β-strand	304-309	6	7
β-strand	315-320	6	1
β-strand	327-331	5	1
β-strand	336-339	4	1

Chain C: 3 helices, 0 β-strands

Element	Residues	Length
α-helix	10-23	14
α-helix	30-43	14
α-helix	53-55	3

Chain E: 7 helices, 25 β-strands

Element	Residues	Length	Sheet
β-strand	3-7	5	12
β-strand	10-12	3	13
β-strand	19-25	7	12
α-helix	29-31	3
β-strand	33-39	7	14
β-strand	45-51	7	14
α-helix	53-55	3
β-strand	58-60	3	14
β-strand	69-73	5	12
β-strand	78-82	5	12
α-helix	88-90	3
β-strand	93-99	7	14
β-strand	110-111	2	14
β-strand	115	1	14
β-strand	117-119	3	13
β-strand	141-143	3	15
β-strand	147-149	3	16
β-strand	156-162	7	15
β-strand	167	1	17
β-strand	173	1	17
β-strand	175-180	6	16
β-strand	187-191	5	16
β-strand	195-196	2	16
α-helix	197	1
β-strand	204-209	6	15
β-strand	212-217	6	15
α-helix	222-224	3
β-strand	227-232	6	16
α-helix	239	1
β-strand	240	1	16
α-helix	241	1
β-strand	244-247	4	16

Chain F: 1 helix, 0 β-strands

Element	Residues	Length	Sheet
α-helix	338-351	14

Chain M: 14 helices, 2 β-strands

Element	Residues	Length	Sheet
α-helix	67-94	28
α-helix	95-99	5
α-helix	104-121	18
α-helix	123-132	10
α-helix	139-172	34
α-helix	174-180	7
α-helix	183-207	25
β-strand	208-213	6	8
β-strand	216-221	6	8
α-helix	227-239	13
α-helix	240-244	5
α-helix	245-263	19
α-helix	271-307	37
α-helix	314-335	22
α-helix	336-340	5
α-helix	343-351	9

Chain R: 16 helices, 2 β-strands

Element	Residues	Length	Sheet
α-helix	67-94	28
α-helix	95-99	5
α-helix	104-120	17
α-helix	123-132	10
α-helix	139-172	34
α-helix	174-180	7
α-helix	183-207	25
β-strand	208-213	6	9
β-strand	216-221	6	9
α-helix	224	1
α-helix	227-239	13
α-helix	240-244	5
α-helix	245-262	18
α-helix	265-267	3
α-helix	271-307	37
α-helix	314-335	22
α-helix	336-340	5
α-helix	343-351	9

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Guanine nucleotide-binding protein G(I)/G(S)/G(T) subunit beta-1	B	protein	345	Rattus norvegicus	P54311 (AlphaFold model)
Guanine nucleotide-binding protein G(I)/G(S)/G(O) subunit gamma-2	C	protein	68	Bos taurus	P63212 (AlphaFold model)
Guanine nucleotide-binding protein G(i) subunit alpha-1	A, F	protein	354	Homo sapiens	P63096 (AlphaFold model)
Mu-type opioid receptor	M, R	protein	400	Homo sapiens	P35372 (AlphaFold model)
scFv16	E	protein	247	synthetic construct

Sequence of entity 1 (B), FASTA

>23SO_1 Guanine nucleotide-binding protein G(I)/G(S)/G(T) subunit beta-1 (chains B)
MGSLLQSELDQLRQEAEQLKNQIRDARKACADATLSQITNNIDPVGRIQMRTRRTLRGHL
AKIYAMHWGTDSRLLVSASQDGKLIIWDSYTTNKVHAIPLRSSWVMTCAYAPSGNYVACG
GLDNICSIYNLKTREGNVRVSRELAGHTGYLSCCRFLDDNQIVTSSGDTTCALWDIETGQ
QTTTFTGHTGDVMSLSLAPDTRLFVSGACDASAKLWDVREGMCRQTFTGHESDINAICFF
PNGNAFATGSDDATCRLFDLRADQELMTYSHDNIICGITSVSFSKSGRLLLAGYDDFNCN
VWDALKADRAGVLAGHDNRVSCLGVTDDGMAVATGSWDSFLKIWN

Sequence of entity 2 (C), FASTA

>23SO_2 Guanine nucleotide-binding protein G(I)/G(S)/G(O) subunit gamma-2 (chains C)
MASNNTASIAQARKLVEQLKMEANIDRIKVSKAAADLMAYCEAHAKEDPLLTPVPASENP
FREKKFFC

Sequence of entity 3 (A, F), FASTA

>23SO_3 Guanine nucleotide-binding protein G(i) subunit alpha-1 (chains A, F)
MGCTLSAEDKAAVERSKMIDRNLREDGEKAAREVKLLLLGAGESGKSTIVKQMKIIHEAG
YSEEECKQYKAVVYSNTIQSIIAIIRAMGRLKIDFGDSARADDARQLFVLAGAAEEGFMT
AELAGVIKRLWKDSGVQACFNRSREYQLNDSAAYYLNDLDRIAQPNYIPTQQDVLRTRVK
TTGIVETHFTFKDLHFKMFDVGAQRSERKKWIHCFEGVTAIIFCVALSDYDLVLAEDEEM
NRMHESMKLFDSICNNKWFTDTSIILFLNKKDLFEEKIKKSPLTICYPEYAGSNTYEEAA
AYIQCQFEDLNKRKDTKEIYTHFTCSTDTKNVQFVFDAVTDVIIKNNLKDCGLF

Sequence of entity 4 (M, R), FASTA

>23SO_4 Mu-type opioid receptor (chains M, R)
MDSSAAPTNASNCTDALAYSSCSPAPSPGSWVNLSHLDGNLSDPCGPNRTDLGGRDSLCP
PTGSPSMITAITIMALYSIVCVVGLFGNFLVMYVIVRYTKMKTATNIYIFNLALADALAT
STLPFQSVNYLMGTWPFGTILCKIVISIDYYNMFTSIFTLCTMSVDRYIAVCHPVKALDF
RTPRNAKIINVCNWILSSAIGLPVMFMATTKYRQGSIDCTLTFSHPTWYWENLLKICVFI
FAFIMPVLIITVCYGLMILRLKSVRMLSGSKEKDRNLRRITRMVLVVVAVFIVCWTPIHI
YVIIKALVTIPETTFQTVSWHFCIALGYTNSCLNPVLYAFLDENFKRCFREFCIPTSSNI
EQQNSTRIRQNTRDHPSTANTVDRTNHQLENLEAETAPLP

Sequence of entity 5 (E), FASTA

>23SO_5 scFv16 (chains E)
VQLVESGGGLVQPGGSRKLSCSASGFAFSSFGMHWVRQAPEKGLEWVAYISSGSGTIYYA
DTVKGRFTISRDDPKNTLFLQMTSLRSEDTAMYYCVRSIYYYGSSPFDFWGQGTTLTVSA
GGGGSGGGGSGGGGSADIVMTQATSSVPVTPGESVSISCRSSKSLLHSNGNTYLYWFLQR
PGQSPQLLIYRMSNLASGVPDRFSGSGSGTAFTLTISRLEAEDVGVYYCMQHLEYPLTFG
AGTKLEL

Ligands and cofactors

ID	Name	Formula	Copies
CLR	Cholesterol	C27 H46 O	10
A1E5L	Cebranopadol	C24 H27 F N2 O	2

Primary citation

Cryo-EM structure of the cebranopadol-mu opioid receptor-Gi complex. Lai, Y., Huang, X., Shen, S. et al. To be published.

Other PDB entries of the same protein (UniProt P54311 (AlphaFold model), which also has an AlphaFold model), best resolution first:

7MBX 1.95 Å, Human Cholecystokinin 1 receptor (CCK1R) Gs complex
9EJZ 2.06 Å, Human M5 muscarinic acetylcholine receptor complex with mini-Gq, agonist acetylcholine…
9IJE 2.34 Å, Epinephrine-activated human beta3 adrenergic receptor
8YK0 2.4 Å, Cryo-EM structure of human GPR156-Gi3 complex
8Z9O 2.4 Å, Cryo-EM structure of human GPR4-Gs complex
22ES 2.43 Å, Gi bound kappa-opioid receptor in complex with difelikefalin
7MBY 2.44 Å, Human Cholecystokinin 1 receptor (CCK1R) Gq chimera (mGsqi) complex
9WG6 2.44 Å, D1R-Gs in complexed with Dopamine/LY3154207/BMSA1/UNC9815
8JIS 2.46 Å, Cryo-EM structure of the GLP-1R/GCGR dual agonist peptide15-bound human GLP-1R-Gs complex
9M0R 2.47 Å, Structure of neuropeptide FF receptor 1 complex with NPVF
8YKV 2.48 Å, Cryo-EM structure of succinate receptor SUCR1 bound to compound 31
9M1O 2.49 Å, Cryo-EM structures of NPFFR2 complex with neuropeptide FF

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