9QTO: Human alpha7 nicotinic receptor

Human alpha7 nicotinic receptor in complex with the E6 nanobody. Determined by electron microscopy at 2.16 Å resolution. Released 18 Feb 2026.

Method: Electron microscopy
Resolution: 2.16 Å
Organisms: Homo sapiens, Vicugna pacos
Chains: 10
Atoms: 14,352
Mol. weight: 310.71 kDa
Released: 18 Feb 2026

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

Secondary structure: helices and β-sheets

9QTO contains 31 α-helices and 149 β-strands across 10 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: 3 helices, 15 β-strands

Element	Residues	Length	Sheet
α-helix	2-10	9
β-strand	28-43	16	1
β-strand	48-65	18	1
α-helix	68-70	3
β-strand	77-79	3	1
β-strand	89-91	3	2
β-strand	94	1	1
β-strand	102	1	1
β-strand	107-109	3	1
β-strand	112-117	6	1
β-strand	120-126	7	1
β-strand	138-147	10	2
β-strand	155-159	5	1
β-strand	163	1	1
α-helix	167-170	4
β-strand	173-177	5	2
β-strand	180-185	6	2
β-strand	194-205	12	2

Chains B and C: 4 helices, 16 β-strands

Element	Residues	Length	Sheet
α-helix	2-10	9
β-strand	28-43	16	3
β-strand	48-65	18	3
α-helix	68-70	3
β-strand	77-79	3	3
β-strand	89-91	3	4
β-strand	94	1	3
β-strand	102	1	3
β-strand	107-109	3	3
β-strand	112-117	6	3
β-strand	120-126	7	3
β-strand	138-147	10	4
β-strand	155-159	5	3
β-strand	163	1	3
α-helix	167	1
β-strand	168	1	3
α-helix	169-170	2
β-strand	173-177	5	4
β-strand	180-185	6	4
β-strand	194-205	12	4

Chain D: 3 helices, 16 β-strands

Element	Residues	Length	Sheet
α-helix	2-10	9
β-strand	28-43	16	7
β-strand	48-65	18	7
β-strand	77-79	3	7
β-strand	89-91	3	8
β-strand	94	1	7
β-strand	102	1	7
β-strand	107-109	3	7
β-strand	112-117	6	7
β-strand	120-126	7	7
β-strand	138-147	10	8
β-strand	155-159	5	7
β-strand	163	1	7
α-helix	167	1
β-strand	168	1	7
α-helix	169-170	2
β-strand	173-177	5	8
β-strand	180-185	6	8
β-strand	194-205	12	8

Chain E: 3 helices, 15 β-strands

Element	Residues	Length	Sheet
α-helix	2-10	9
β-strand	28-43	16	9
β-strand	48-65	18	9
β-strand	77-79	3	9
β-strand	89-91	3	10
β-strand	94	1	9
β-strand	102	1	9
β-strand	107-109	3	9
β-strand	112-117	6	9
β-strand	120-126	7	9
β-strand	138-147	10	10
β-strand	155-159	5	9
α-helix	161-162	2
β-strand	163	1	9
α-helix	167-170	4
β-strand	173-177	5	10
β-strand	180-185	6	10
β-strand	194-205	12	10

Chains F and H: 4 helices, 14 β-strands

Element	Residues	Length	Sheet
β-strand	6	1	11
β-strand	8	1	12
β-strand	12-13	2	13
β-strand	19-22	4	12
β-strand	34-40	7	14
β-strand	47-53	7	14
β-strand	58-61	4	14
β-strand	69-74	6	12
β-strand	79-84	6	12
α-helix	89-91	3
β-strand	93-100	8	14
α-helix	109-111	3
β-strand	115-116	2	14
α-helix	117	1
β-strand	118	1	11
α-helix	119	1
β-strand	120-122	3	14
β-strand	123-124	2	13

Chains G and I: 2 helices, 14 β-strands

Element	Residues	Length	Sheet
β-strand	6	1	15
β-strand	8	1	16
β-strand	12-13	2	17
β-strand	19-22	4	16
β-strand	34-40	7	18
β-strand	47-53	7	18
β-strand	58-61	4	18
β-strand	69-74	6	16
β-strand	79-84	6	16
α-helix	89-91	3
β-strand	93-100	8	18
α-helix	109-111	3
β-strand	115-116	2	18
β-strand	118	1	15
β-strand	120-122	3	18
β-strand	123-124	2	17

Chain J: 2 helices, 15 β-strands

Element	Residues	Length	Sheet
β-strand	6	1	27
β-strand	8	1	28
β-strand	12-13	2	29
β-strand	19-22	4	28
β-strand	34-40	7	30
β-strand	46-53	8	30
β-strand	58-61	4	30
β-strand	66	1	28
β-strand	69-74	6	28
β-strand	79-84	6	28
α-helix	89-91	3
β-strand	93-100	8	30
α-helix	109-111	3
β-strand	115-116	2	30
β-strand	118	1	27
β-strand	120-122	3	30
β-strand	123-124	2	29

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Neuronal acetylcholine receptor subunit alpha-7,CHRNA7 (exons 5-10) and FAM7A (exons A-E) fusion	A, B, C, D, E	protein	375	Homo sapiens	P36544 (AlphaFold model)
Nanobody E6	F, G, H, I, J	protein	159	Vicugna pacos

Sequence of entity 1 (A, B, C, D, E), FASTA

>9QTO_1 Neuronal acetylcholine receptor subunit alpha-7,CHRNA7 (exons 5-10) and FAM7A (exons A-E) fusion (chains A, B, C, D, E)
EFQRKLYKELVKNYNPLERPVANDSQPLTVYFSLSLLQIMDVDEKNQVLTTNIWLQMSWT
DHYLQWNVSEYPGVKTVRFPDGQIWKPDILLYNSADERFDATFHTNVLVNSSGHCQYLPP
GIFKSSCYIDVRWFPFDVQHCKLKFGSWSYGGWSLDLQMQEADISGYIPNGEWDLVGIPG
KRSERFYECCKEPYPDVTFTVTMRRRTLYYGLNLLIPCVLISALALLVFLLPADSGEKIS
LGITVLLSLTVFMLLVAEIMPATSDSVPLIAQYFASTMIIVGLSVVVTVIVLQYHHHDPD
GGKMPKWTRVILLNWCAWFLRMKRDGVAVCSEWKFAACVVDRLCLMAFSVFTIICTIGIL
MSAPNFVEAVSKDFA

Sequence of entity 2 (F, G, H, I, J), FASTA

>9QTO_2 Nanobody E6 (chains F, G, H, I, J)
AQLQLVESGGGLVQPGGSLRLSCAASGFTLDYYTIGWFRQAPGKEREGVSCIRGSGGSTN
YADSVKGRFTISRDNAKNTVYLQMNSLKPEDTAVYYCAADFLSTCSLAGYRYEEVWGQGT
LVTVSSAHHSEDPSAAAEQKLISEEDLNGAAHHHHHHGS

Primary citation

Discovery and mechanism of negative allosteric modulation of the alpha 7 nicotinic acetylcholine receptor by nanobodies. Barilone, N., Vangelatou, M., Marouf, F.Z. et al. Proc Natl Acad Sci U S A (2026) 123:e2514734123-e2514734123. DOI 10.1073/pnas.2514734123 · PubMed

Other PDB entries of the same protein (UniProt P36544 (AlphaFold model), which also has an AlphaFold model), best resolution first:

8P1H 1.95 Å, Crystal structure of the chimera of human 14-3-3 zeta and phosphorylated cytoplasmic…
5AFN 2.15 Å, alpha7-AChBP in complex with lobeline and fragment 5
8V8A 2.19 Å, Alpha7-nicotinic acetylcholine receptor time resolved bound to epibatidine and…
5AFJ 2.2 Å, alpha7-AChBP in complex with lobeline and fragment 1
9QTN 2.28 Å, Human alpha7 nicotinic receptor in complex with the F1 nanobody
8C9X 2.3 Å, human alpha7 nicotinic receptor in complex with the C4 nanobody
8UT1 2.3 Å, Alpha7-nicotinic acetylcholine receptor bound to epibatidine
8UTB 2.3 Å, Alpha7-nicotinic acetylcholine receptor bound to epibatidine and NS-1738
8UZJ 2.3 Å, Alpha7-nicotinic acetylcholine receptor bound to epibatidine and ivermectin
8V88 2.3 Å, Alpha7-nicotinic acetylcholine receptor bound to epibatidine and GAT107
8V80 2.34 Å, Alpha7-nicotinic acetylcholine receptor bound to epibatidine and (-)-TQS
5AFK 2.38 Å, alpha7-AChBP in complex with lobeline and fragment 2

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