9LL9: PDB entry 9LL9

DOI-bound Serotonin 2A (5-HT2A) receptor-Gq complex. Determined by electron microscopy at 2.76 Å resolution. Released 14 Jan 2026.

Method: Electron microscopy
Resolution: 2.76 Å
Organism: Homo sapiens
Chains: 4
Atoms: 6,894
Mol. weight: 140.3 kDa
Ligands: CLR, A1EK5
Released: 14 Jan 2026

Explore 9LL9 in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9LL9 contains 28 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	7-30	24
β-strand	33-37	5	8
α-helix	46-55	10
β-strand	184-190	7	8
β-strand	195-201	7	8
β-strand	220-226	7	8
α-helix	233-244	12
β-strand	253-259	7	8
α-helix	261-269	9
α-helix	280-282	3
α-helix	292-294	3
α-helix	299-317	19
β-strand	326-330	5	8
α-helix	338-357	20

Chain B: 2 helices, 28 β-strands

Element	Residues	Length	Sheet
α-helix	4-24	21
α-helix	30-34	5
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	88-94	7	2
β-strand	100-105	6	3
β-strand	111-116	6	3
β-strand	120-125	6	3
β-strand	134-140	7	3
β-strand	146-151	6	4
β-strand	156-161	6	4
β-strand	165-170	6	4
β-strand	175-180	6	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	232-234	3	6
β-strand	240-243	4	6
β-strand	250-254	5	6
β-strand	259-264	6	6
β-strand	273-278	6	7
β-strand	284-289	6	7
β-strand	294-298	5	7
β-strand	304-308	5	7
β-strand	315-320	6	1
β-strand	327-331	5	1
β-strand	336-339	4	1

Chain C: 4 helices, 0 β-strands

Element	Residues	Length
α-helix	12-23	12
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	79-100	22
α-helix	108-126	19
α-helix	128-136	9
α-helix	145-147	3
α-helix	148-178	31
α-helix	180-185	6
α-helix	189-207	19
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	357-379	23
α-helix	385-392	8

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,Guanine nucleotide-binding protein G(s)…	A	protein	361	Homo sapiens	P50148 (AlphaFold model), P63092 (AlphaFold model), P63096
5-hydroxytryptamine receptor 2A	R	protein	471	Homo sapiens	P28223

Sequence of entity 1 (B), FASTA

>9LL9_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

>9LL9_2 Guanine nucleotide-binding protein G(I)/G(S)/G(O) subunit gamma-2 (chains C)
MASNNTASIAQARKLVEQLKMEANIDRIKVSKAAADLMAYCEAHAKEDPLLTPVPASENP
FREKKFFCAIL

Sequence of entity 3 (A), FASTA

>9LL9_3 Guanine nucleotide-binding protein G(i) subunit alpha-1,Guanine nucleotide-binding protein G(s) subunit alpha isoforms short,Guanine nucleotide-binding protein G(q) subunit alpha (chains A)
MGCTLSAEDKAAVERSKMIEKQLQKDKQVYRRTLRLLLLGADNSGKSTIVKQMRIYHVNG
YSEEECKQYKAVVYSNTIQSIIAIIRAMGRLKIDFGDSARADDARQLSVLAGAAEEGFMT
AELAGVIKRLWKDSGVQACFNRSREYQLNDSAAYYLNDLDRIAQPNYIPTQQDVLRTRVK
TSGIFETKFQVDKVNFHMFDVGAQRDERRKWIQCFNDVTAIIFVVDSSDYNRLQEALNDF
KSIWNNRWLRTISVILFLNKQDLLAEKVLAGKSKIEDYFPEFARYTTPEDATPEPGEDPR
VTRAKYFIRKEFVDISTASGDGRHICYPHFTCSVDTENARRIFNDCKDIILQMNLREYNL
V

Sequence of entity 4 (R), FASTA

>9LL9_4 5-hydroxytryptamine receptor 2A (chains R)
MDILCEENTSLSSTTNSLMQLNDDTRLYSNDFNSGEANTSDAFNWTVDSENRTNLSCEGC
LSPSCLSLLHLQEKNWSALLTAVVIILTIAGNILVIMAVSLEKKLQNATNYFLMSLAIAD
MLLGFLVMPVSMLTILYGYRWPLPSKLCAVWIYLDVLFSTASIMHLCAISLDRYVAIQNP
IHHSRFNSRTKAFLKIIAVWTISVGISMPIPVFGLQDDSKVFKEGSCLLADDNFVLIGSF
VSFFIPLTIMVITYFLTIKSLQKEATLCVSDLGTRAKLASFSFLPQSSLSSEKLFQRSIH
REPGSYTGRRTMQSISNEQKACKVLGIVFFLFVVMWCPFFITNIMAVICKESCNEDVIGA
LLNVFVWIGYLSSAVNPLVYTLFNKTYRSAFSRYIQCQYKENKKPLQLILVNTIPALAYK
SSQLQMGQKKNSKQDAKTTDNDCSMVALGKQHSEEASKDNSDGVNEKVSCV

Ligands and cofactors

ID	Name	Formula	Copies
CLR	Cholesterol	C27 H46 O	1
A1EK5	(2~{R})-1-(4-iodanyl-2,5-dimethoxy-phenyl)propan-2-amine	C11 H16 I N O2	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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