9PA5: (S)-ketamine bound mu-opioid receptor

(S)-ketamine bound mu-opioid receptor in complex with Gi1. Determined by electron microscopy at 2.92 Å resolution. Released 1 Jul 2026.

Method: Electron microscopy
Resolution: 2.92 Å
Organisms: Homo sapiens, Mus musculus
Chains: 5
Atoms: 8,516
Mol. weight: 147.64 kDa
Ligands: JC9
Released: 1 Jul 2026

Explore 9PA5 in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9PA5 contains 34 α-helices and 60 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 A: 10 helices, 7 β-strands

Element	Residues	Length	Sheet
α-helix	7-31	25
β-strand	33-35	3	1
β-strand	38-40	3	1
α-helix	43-51	9
β-strand	185-190	6	1
β-strand	195-200	6	1
α-helix	209-212	4
α-helix	213-215	3
β-strand	220-224	5	1
α-helix	227-229	3
α-helix	242-254	13
α-helix	257-259	3
β-strand	263-268	6	1
α-helix	271-279	9
α-helix	296-308	13
β-strand	319-323	5	1
α-helix	329-350	22

Chain B: 4 helices, 28 β-strands

Element	Residues	Length	Sheet
α-helix	3-25	23
α-helix	30-34	5
α-helix	38-39	2
β-strand	47-51	5	2
β-strand	58-63	6	3
β-strand	69-74	6	3
β-strand	78-83	6	3
β-strand	88-94	7	3
β-strand	100-105	6	4
β-strand	111-116	6	4
β-strand	121-125	5	4
β-strand	134-139	6	4
β-strand	146-151	6	5
β-strand	156-161	6	5
β-strand	166-170	5	5
β-strand	176-180	5	5
β-strand	187-192	6	6
β-strand	198-203	6	6
β-strand	207-212	6	6
β-strand	218-223	6	6
β-strand	229-234	6	7
β-strand	240-245	6	7
β-strand	250-254	5	7
β-strand	259-264	6	7
α-helix	272	1
β-strand	273-278	6	8
β-strand	284-289	6	8
β-strand	294-298	5	8
β-strand	304-308	5	8
β-strand	315-320	6	2
β-strand	327-331	5	2
β-strand	335-339	5	2

Chain C: 4 helices, 0 β-strands

Element	Residues	Length
α-helix	6-22	17
α-helix	30-43	14
α-helix	54-55	2
α-helix	56-58	3

Chain E: 3 helices, 25 β-strands

Element	Residues	Length	Sheet
β-strand	3-6	4	9
β-strand	10-11	2	10
β-strand	18-25	8	9
α-helix	29-31	3
β-strand	34-39	6	10
β-strand	45-51	7	10
α-helix	53-55	3
β-strand	58-60	3	10
β-strand	68-73	6	9
β-strand	78-83	6	9
β-strand	92-97	6	10
β-strand	111	1	10
β-strand	115-118	4	10
β-strand	141-142	2	11
β-strand	147-149	3	12
β-strand	155-160	6	13
β-strand	161-162	2	11
β-strand	167	1	14
β-strand	173	1	14
β-strand	175-180	6	12
β-strand	187-191	5	12
β-strand	195-196	2	12
α-helix	197	1
β-strand	205-209	5	13
β-strand	212-218	7	13
β-strand	227-232	6	12
β-strand	240	1	12
β-strand	244-247	4	12

Chain R: 13 helices, 0 β-strands

Element	Residues	Length
α-helix	68-93	26
α-helix	94-98	5
α-helix	104-131	28
α-helix	139-172	34
α-helix	174-180	7
α-helix	183-206	24
α-helix	230-243	14
α-helix	245-262	18
α-helix	265-267	3
α-helix	271-288	18
α-helix	290-307	18
α-helix	314-339	26
α-helix	343-349	7

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Guanine nucleotide-binding protein G(i) subunit alpha-1	A	protein	354	Homo sapiens	P63096 (AlphaFold model)
Mu-type opioid receptor	R	protein	308	Homo sapiens	P35372 (AlphaFold model)
Guanine nucleotide-binding protein G(I)/G(S)/G(T) subunit beta-1	B	protein	340	Homo sapiens	P62873 (AlphaFold model)
Guanine nucleotide-binding protein G(I)/G(S)/G(O) subunit gamma-2	C	protein	71	Homo sapiens	P59768 (AlphaFold model)
ScFv16 protein	E	protein	251	Mus musculus

Sequence of entity 1 (A), FASTA

>9PA5_1 Guanine nucleotide-binding protein G(i) subunit alpha-1 (chains A)
MGCTLSAEDKAAVERSKMIDRNLREDGEKAAREVKLLLLGAGESGKNTIVKQMKIIHEAG
YSEEECKQYKAVVYSNTIQSIIAIIRAMGRLKIDFGDSARADDARQLFVLAGAAEEGFMT
AELAGVIKRLWKDSGVQACFNRSREYQLNDSAAYYLNDLDRIAQPNYIPTQQDVLRTRVK
TTGIVETHFTFKDLHFKMFDVGAQRSERKKWIHCFEGVTAIIFCVALSDYDLVLAEDEEM
NRMHASMKLFDSICNNKWFTDTSIILFLNKKDLFEEKIKKSPLTICYPEYAGSNTYEEAA
AYIQCQFEDLNKRKDTKEIYTHFTCSTDTKNVQFVFDAVTDVIIKNNLKDCGLF

Sequence of entity 2 (R), FASTA

>9PA5_2 Mu-type opioid receptor (chains R)
GRDSLCPPTGSPSMITAITIMALYSIVCVVGLFGNFLVMYVIVRYTKMKTATNIYIFNLA
LADALATSTLPFQSVNYLMGTWPFGTILCKIVISIDYYNMFTSIWTLCTMSVDRYIAVCH
PVKALDFRTPRNAKIINVCNWILSSAIGLPVMFMATTKYRQGSIDCTLTFSHPTWYWENL
LKICVFIFAFIMPVLIITVCYGLMILRLKSVRMLSGSKEKDRNLRRITRMVLVVVAVFIV
CWTPIHIYVIIKALVTIPETTFQTVSWHFCIALGYTNSCLNPVLYAFLDENFKRCFREFC
IPTSSNIE

Sequence of entity 3 (B), FASTA

>9PA5_3 Guanine nucleotide-binding protein G(I)/G(S)/G(T) subunit beta-1 (chains B)
GSELDQLRQEAEQLKNQIRDARKACADATLSQITNNIDPVGRIQMRTRRTLRGHLAKIYA
MHWGTDSRLLVSASQDGKLIIWDSYTTNKVHAIPLRSSWVMTCAYAPSGNYVACGGLDNI
CSIYNLKTREGNVRVSRELAGHTGYLSCCRFLDDNQIVTSSGDTTCALWDIETGQQTTTF
TGHTGDVMSLSLAPDTRLFVSGACDASAKLWDVREGMCRQTFTGHESDINAICFFPNGNA
FATGSDDATCRLFDLRADQELMTYSHDNIICGITSVSFSKSGRLLLAGYDDFNCNVWDAL
KADRAGVLAGHDNRVSCLGVTDDGMAVATGSWDSFLKIWN

Sequence of entity 4 (C), FASTA

>9PA5_4 Guanine nucleotide-binding protein G(I)/G(S)/G(O) subunit gamma-2 (chains C)
MASNNTASIAQARKLVEQLKMEANIDRIKVSKAAADLMAYCEAHAKEDPLLTPVPASENP
FREKKFFCAIL

Sequence of entity 5 (E), FASTA

>9PA5_5 ScFv16 protein (chains E)
DVQLVESGGGLVQPGGSRKLSCSASGFAFSSFGMHWVRQAPEKGLEWVAYISSGSGTIYY
ADTVKGRFTISRDDPKNTLFLQMTSLRSEDTAMYYCVRSIYYYGSSPFDFWGQGTTLTVS
SGGGGSGGGGSGGGGSDIVMTQATSSVPVTPGESVSISCRSSKSLLHSNGNTYLYWFLQR
PGQSPQLLIYRMSNLASGVPDRFSGSGSGTAFTLTISRLEAEDVGVYYCMQHLEYPLTFG
AGTKLELKAAA

Ligands and cofactors

ID	Name	Formula	Copies
JC9	(2~{S})-2-(2-chlorophenyl)-2-(methylamino)cyclohexan-1-one	C13 H16 Cl N O	1

Primary citation

Structural basis of opioid receptor activation by PCP and ketamine. Jiang, Q., Han, J., Fine, E.J. et al. Nat Struct Mol Biol (2026) 33:1341-1353. DOI 10.1038/s41594-026-01839-y · PubMed

Other PDB entries of the same protein (UniProt P63096 (AlphaFold model), which also has an AlphaFold model), best resolution first:

6CRK 2.0 Å, Heterotrimeric G-protein in complex with an antibody fragment
3UMR 2.04 Å, Crystal structure of the G202D mutant of human G-alpha-i1
9P7Z 2.1 Å, NTSR1-Gi-NTS(8-13) Complex in the Canonical, AHD Open State (C-Open-Apo)
2OM2 2.2 Å, Crystal Structure Of Human G[alpha]i1 Bound To The Goloco Motif Of Rgs14
8YN9 2.3 Å, Cryo-EM structure of histamine H4 receptor in complex with histamine and Gi
9HYI 2.3 Å, DP81-bound serotonin 5-HT1A receptor - Gi Protein Complex
9O36 2.3 Å, CryoEM structure of mu-opioid receptor - Gi protein complex bound to fluornitrazene (FNZ)
9P80 2.3 Å, NTSR1-Gi-NTS(8-13) Complex in the Non-Canonical, AHD Open State (NC-Open-Apo)
8XXV 2.33 Å, Cryo-EM Structure of the Prostaglandin D2 Receptor 2-indomethacin Coupled to G Protein
3UMS 2.34 Å, Crystal structure of the G202A mutant of human G-alpha-i1
3ONW 2.38 Å, Structure of a G-alpha-i1 mutant with enhanced affinity for the RGS14 GoLoco motif.
20ZG 2.4 Å, Cryo-EM structure of the human neurotensin receptor 1 (hNTSR1)-Gi1 complex in the…

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