9LL8: PDB entry 9LL8

Psilocin-bound Serotonin 2A (5-HT2A) receptor-Gi complex. Determined by electron microscopy at 2.62 Å resolution. Released 14 Jan 2026.

Method: Electron microscopy
Resolution: 2.62 Å
Organism: Homo sapiens
Chains: 4
Atoms: 6,926
Mol. weight: 138.64 kDa
Ligands: 91Q, CLR
Released: 14 Jan 2026

Explore 9LL8 in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9LL8 contains 30 α-helices and 36 β-strands across 4 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: 8 helices, 6 β-strands

Element	Residues	Length	Sheet
α-helix	7-29	23
β-strand	34-39	6	8
α-helix	46-52	7
α-helix	54-56	3
β-strand	185-191	7	8
β-strand	194-200	7	8
α-helix	212-215	4
β-strand	220-226	7	8
α-helix	244-254	11
β-strand	263-269	7	8
α-helix	271-280	10
α-helix	296-308	13
β-strand	319-323	5	8
α-helix	330-350	21

Chain B: 4 helices, 28 β-strands

Element	Residues	Length	Sheet
α-helix	2-24	23
α-helix	30-33	4
α-helix	38-43	6
β-strand	47-52	6	1
β-strand	58-63	6	2
β-strand	69-74	6	2
β-strand	78-83	6	2
β-strand	88-94	7	2
β-strand	100-105	6	3
β-strand	111-116	6	3
β-strand	121-125	5	3
β-strand	134-139	6	3
α-helix	145	1
β-strand	146-151	6	4
β-strand	156-161	6	4
β-strand	166-170	5	4
β-strand	176-180	5	4
β-strand	189-192	4	5
β-strand	198-202	5	5
β-strand	207-212	6	5
β-strand	218-223	6	5
β-strand	229-234	6	6
β-strand	240-245	6	6
β-strand	249-254	6	6
β-strand	260-265	6	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	335-339	5	1

Chain C: 4 helices, 0 β-strands

Element	Residues	Length
α-helix	7-23	17
α-helix	30-43	14
α-helix	53-55	3
α-helix	56-58	3

Chain R: 14 helices, 2 β-strands

Element	Residues	Length	Sheet
α-helix	81-101	21
α-helix	108-122	15
α-helix	123-127	5
α-helix	128-136	9
α-helix	148-178	31
α-helix	180-185	6
α-helix	189-206	18
α-helix	209-214	6
β-strand	222-223	2	9
β-strand	226-227	2	9
α-helix	233-239	7
α-helix	240-244	5
α-helix	245-260	16
α-helix	316-348	33
α-helix	355-380	26
α-helix	385-391	7

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
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)
Guanine nucleotide-binding protein G(i) subunit alpha-1	A	protein	351	Homo sapiens	P63096 (AlphaFold model)
5-hydroxytryptamine receptor 2A	R	protein	471	Homo sapiens	P28223 (AlphaFold model)

Sequence of entity 1 (B), FASTA

>9LL8_1 Guanine nucleotide-binding protein G(I)/G(S)/G(T) subunit beta-1 (chains B)
MSELDQLRQEAEQLKNQIRDARKACADATLSQITNNIDPVGRIQMRTRRTLRGHLAKIYA
MHWGTDSRLLVSASQDGKLIIWDSYTTNKVHAIPLRSSWVMTCAYAPSGNYVACGGLDNI
CSIYNLKTREGNVRVSRELAGHTGYLSCCRFLDDNQIVTSSGDTTCALWDIETGQQTTTF
TGHTGDVMSLSLAPDTRLFVSGACDASAKLWDVREGMCRQTFTGHESDINAICFFPNGNA
FATGSDDATCRLFDLRADQELMTYSHDNIICGITSVSFSKSGRLLLAGYDDFNCNVWDAL
KADRAGVLAGHDNRVSCLGVTDDGMAVATGSWDSFLKIWN

Sequence of entity 2 (C), FASTA

>9LL8_2 Guanine nucleotide-binding protein G(I)/G(S)/G(O) subunit gamma-2 (chains C)
MASNNTASIAQARKLVEQLKMEANIDRIKVSKAAADLMAYCEAHAKEDPLLTPVPASENP
FREKKFFCAIL

Sequence of entity 3 (A), FASTA

>9LL8_3 Guanine nucleotide-binding protein G(i) subunit alpha-1 (chains A)
TLSAEDKAAVERSKMIDRNLREDGEKAAREVKLLLLGAGESGKNTIVKQMKIIHEAGYSE
EECKQYKAVVYSNTIQSIIAIIRAMGRLKIDFGDSARADDARQLFVLAGAAEEGFMTAEL
AGVIKRLWKDSGVQACFNRSREYQLNDSAAYYLNDLDRIAQPNYIPTQQDVLRTRVKTTG
IVETHFTFKDLHFKMFDVGAQRSERKKWIHCFEGVTAIIFCVALSDYDLVLAEDEEMNRM
HASMKLFDSICNNKWFTDTSIILFLNKKDLFEEKIKKSPLTICYPEYAGSNTYEEAAAYI
QCQFEDLNKRKDTKEIYTHFTCSTDTKNVQFVFDAVTDVIIKNNLKDCGLF

Sequence of entity 4 (R), FASTA

>9LL8_4 5-hydroxytryptamine receptor 2A (chains R)
MDILCEENTSLSSTTNSLMQLNDDTRLYSNDFNSGEANTSDAFNWTVDSENRTNLSCEGC
LSPSCLSLLHLQEKNWSALLTAVVIILTIAGNILVIMAVSLEKKLQNATNYFLMSLAIAD
MLLGFLVMPVSMLTILYGYRWPLPSKLCAVWIYLDVLFSTASIMHLCAISLDRYVAIQNP
IHHSRFNSRTKAFLKIIAVWTISVGISMPIPVFGLQDDSKVFKEGSCLLADDNFVLIGSF
VSFFIPLTIMVITYFLTIKSLQKEATLCVSDLGTRAKLASFSFLPQSSLSSEKLFQRSIH
REPGSYTGRRTMQSISNEQKACKVLGIVFFLFVVMWCPFFITNIMAVICKESCNEDVIGA
LLNVFVWIGYLSSAVNPLVYTLFNKTYRSAFSRYIQCQYKENKKPLQLILVNTIPALAYK
SSQLQMGQKKNSKQDAKTTDNDCSMVALGKQHSEEASKDNSDGVNEKVSCV

Ligands and cofactors

ID	Name	Formula	Copies
91Q	3-[2-(dimethylamino)ethyl]-1~{H}-indol-4-ol	C12 H16 N2 O	1
CLR	Cholesterol	C27 H46 O	1

Primary citation

Psychedelics elicit their effects by 5-HT 2A receptor-mediated G i signalling. Xu, Z., Wang, H., Yu, J. et al. Nature (2026) 651:829-837. DOI 10.1038/s41586-025-10061-7 · PubMed

Other PDB entries of the same protein (UniProt P62873 (AlphaFold model), which also has an AlphaFold model), best resolution first:

8QEH 1.43 Å, Crystal structure of the G11 protein heterotrimer bound to FR900359 inhibitor
8QEG 1.7 Å, Crystal structure of the G11 protein heterotrimer bound to YM-254890 inhibitor
8F0K 1.9 Å, Human Amylin3 Receptor in complex with Gs and Pramlintide analogue peptide San385
9YDQ 1.94 Å, Human delta opioid receptor complex with mini-Gi and agonist DADLE and allosteric…
9YDP 1.95 Å, Human delta opioid receptor complex with mini-Gi and agonist DADLE
6CRK 2.0 Å, Heterotrimeric G-protein in complex with an antibody fragment
8F0J 2.0 Å, Calcitonin Receptor in complex with Gs and Pramlintide analogue peptide San45
8F2B 2.0 Å, Amylin 3 Receptor in complex with Gs and Pramlintide analogue peptide San45
9XXT 2.0 Å, Cryo-EM structure of lysophosphatidylserine (18:0)-bound GPR174-Gs complex
6X18 2.1 Å, GLP-1 peptide hormone bound to Glucagon-Like peptide-1 (GLP-1) Receptor
6X19 2.1 Å, Non peptide agonist CHU-128, bound to Glucagon-Like peptide-1 (GLP-1) Receptor
9NTU 2.1 Å, Cryo-EM structure of BETP-GLP-1(9-36)-GLP-1R-Gs complex

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