9HNR: PDB entry 9HNR

a5b3 GABAA Receptor in 1 a5 to 4 b3 stoichiometry in desensitized state. Determined by electron microscopy at 3.17 Å resolution. Released 24 Dec 2025.

Method: Electron microscopy
Resolution: 3.17 Å
Organisms: Aequorea victoria, Homo sapiens, Escherichia coli
Chains: 8
Atoms: 17,148
Mol. weight: 543.56 kDa
Ligands: ABU
Released: 24 Dec 2025

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

Secondary structure: helices and β-sheets

9HNR contains 79 α-helices and 97 β-strands across 8 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: 12 helices, 15 β-strands

Element	Residues	Length	Sheet
α-helix	13-22	10
β-strand	41-56	16	1
β-strand	61-73	13	1
α-helix	75-77	3
β-strand	85-88	4	1
α-helix	90-94	5
β-strand	102-103	2	2
β-strand	106-111	6	1
β-strand	119-124	6	1
β-strand	128-140	13	1
α-helix	148-150	3
β-strand	152-160	9	2
β-strand	169-173	5	1
β-strand	174	1	3
β-strand	176	1	3
β-strand	181-183	3	1
β-strand	188	1	1
β-strand	193-207	15	2
β-strand	210-223	14	2
α-helix	226-228	3
α-helix	229-233	5
α-helix	234-244	11
α-helix	245-248	4
α-helix	254-275	22
α-helix	276-278	3
α-helix	287-315	29
α-helix	324-349	26

Chain B: 15 helices, 12 β-strands

Element	Residues	Length	Sheet
α-helix	8-20	13
α-helix	35	1
β-strand	36-51	16	4
β-strand	56-68	13	4
α-helix	70-72	3
β-strand	82-83	2	4
α-helix	85-90	6
β-strand	96-98	3	5
β-strand	101-106	6	4
β-strand	114-118	5	4
β-strand	123-135	13	4
α-helix	140-142	3
β-strand	147-156	10	5
β-strand	164-168	5	4
α-helix	171-174	4
β-strand	175-176	2	4
α-helix	178-180	3
β-strand	186-200	15	5
β-strand	203-216	14	5
α-helix	219-221	3
α-helix	222-226	5
α-helix	227-237	11
α-helix	238-240	3
α-helix	247-268	22
α-helix	269-271	3
α-helix	280-307	28
α-helix	553-581	29

Chain C: 15 helices, 12 β-strands

Element	Residues	Length	Sheet
α-helix	9-20	12
α-helix	35	1
β-strand	36-51	16	6
β-strand	56-68	13	6
α-helix	70-72	3
β-strand	81-82	2	6
α-helix	85-90	6
β-strand	96-98	3	7
β-strand	101-106	6	6
β-strand	114-118	5	6
β-strand	123-135	13	6
α-helix	140-145	6
β-strand	147-156	10	7
β-strand	164-168	5	6
α-helix	171-174	4
β-strand	175-176	2	6
α-helix	178-180	3
β-strand	186-200	15	7
β-strand	203-216	14	7
α-helix	219-221	3
α-helix	222-226	5
α-helix	227-236	10
α-helix	237-240	4
α-helix	247-271	25
α-helix	278-279	2
α-helix	280-307	28
α-helix	550-583	34

Chain D: 15 helices, 12 β-strands

Element	Residues	Length	Sheet
α-helix	9-20	12
α-helix	35	1
β-strand	36-51	16	8
β-strand	56-68	13	8
α-helix	70-72	3
β-strand	81	1	8
α-helix	85-90	6
β-strand	96-98	3	9
β-strand	101-106	6	8
β-strand	114-118	5	8
β-strand	123-135	13	8
α-helix	140-145	6
β-strand	147-156	10	9
β-strand	164-168	5	8
α-helix	171-174	4
β-strand	175-176	2	8
α-helix	178-180	3
β-strand	186-200	15	9
β-strand	203-216	14	9
α-helix	219-221	3
α-helix	222-226	5
α-helix	227-236	10
α-helix	237-240	4
α-helix	247-271	25
α-helix	278-279	2
α-helix	280-306	27
α-helix	551-583	33

Chain E: 13 helices, 12 β-strands

Element	Residues	Length	Sheet
α-helix	8-20	13
α-helix	35	1
β-strand	36-51	16	10
β-strand	56-68	13	10
α-helix	70-72	3
β-strand	81-83	3	10
α-helix	85-90	6
β-strand	96-98	3	11
β-strand	101-106	6	10
β-strand	114-118	5	10
β-strand	123-135	13	10
α-helix	140-142	3
β-strand	147-156	10	11
β-strand	164-168	5	10
α-helix	171-173	3
β-strand	175-176	2	10
β-strand	186-200	15	11
β-strand	203-216	14	11
α-helix	219-221	3
α-helix	222-226	5
α-helix	227-237	11
α-helix	238-240	3
α-helix	247-269	23
α-helix	280-306	27
α-helix	553-581	29

Chain P: 3 helices, 11 β-strands

Element	Residues	Length	Sheet
β-strand	2-7	6	12
β-strand	10-11	2	13
β-strand	404-413	10	12
α-helix	415-417	3
β-strand	420-426	7	13
β-strand	433-439	7	13
β-strand	445-447	3	13
β-strand	456-460	5	12
β-strand	465-471	7	12
α-helix	475-477	3
β-strand	479-486	8	13
α-helix	496-498	3
β-strand	499-502	4	13
β-strand	506-509	4	13

Chain Q: 3 helices, 11 β-strands

Element	Residues	Length	Sheet
β-strand	3-7	5	14
β-strand	10-11	2	15
β-strand	406-412	7	14
α-helix	415-417	3
β-strand	420-426	7	15
β-strand	433-439	7	15
β-strand	445-447	3	15
β-strand	456-460	5	14
β-strand	465-469	5	14
α-helix	475-477	3
β-strand	479-486	8	15
α-helix	496-498	3
β-strand	499-502	4	15
β-strand	506-509	4	15

Chain R: 3 helices, 12 β-strands

Element	Residues	Length	Sheet
β-strand	2-7	6	16
β-strand	10-11	2	17
β-strand	404-413	10	16
α-helix	415-417	3
β-strand	420-426	7	17
β-strand	433-439	7	17
β-strand	445-447	3	17
β-strand	452	1	16
β-strand	455-460	6	16
β-strand	465-471	7	16
α-helix	475-477	3
β-strand	479-486	8	17
α-helix	496-498	3
β-strand	499-502	4	17
β-strand	506-509	4	17

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Green fluorescent protein,Gamma-aminobutyric acid receptor subunit alpha-5	A	protein	679	Aequorea victoria, Homo sapiens	P31644 (AlphaFold model)
Gamma-aminobutyric acid receptor subunit beta-3,Green fluorescent protein	B, C, D, E	protein	623	Homo sapiens	P28472 (AlphaFold model)
Megabody 25	P, Q, R	protein	541	Escherichia coli

Sequence of entity 1 (A), FASTA

>9HNR_1 Green fluorescent protein,Gamma-aminobutyric acid receptor subunit alpha-5 (chains A)
MRKSPGLSDCLWAWILLLSTLTGRSYGQMSKGEELFTGVVPILVELDGDVNGHKFSVRGE
GEGDATNGKLTLKFICTTGKLPVPWPTLVTTLTYGVQCFSRYPDHMKRHDFFKSAMPEGY
VQERTISFKDDGTYKTRAEVKFEGDTLVNRIELKGIDFKEDGNILGHKLEYNFNSHNVYI
TADKQKNGIKANFKIRHNVEDGSVQLADHYQQNTPIGDGPVLLPDNHYLSTQSVLSKDPN
EKRDHMVLLEFVTAAGITHGMDELYKAANALAAWSHPQFEKGGGSGGGSGGGSWSHPQFE
KSSSNNNNNENLYFQAMPTSSVKDETNDNITIFTRILDGLLDGYDNRLRPGLGERITQVR
TDIYVTSFGPVSDTEMEYTIDVFFRQSWKDERLRFKGPMQRLPLNNLLASKIWTPDTFFH
NGKKSIAHNMTTPNKLLRLEDDGTLLYTMRLTISAECPMQLEDFPMDAHACPLKFGSYAY
PNSEVVYVWTNGSTKSVVVAEDGSRLNQYHLMGQTVGTENISTSTGEYTIMTAHFHLKRK
IGYFVIQTYLPCIMTVILSQVSFWLNRESVPARTVFGVTTVLTMTTLSISARNSLPKVAY
ATAMDWFIAVCYAFVFSALIEFATVNYFTKSQPARAASISKIDKMSRIVFPVLFGTFNLV
YWATYLNREPVIKGAASPK

Sequence of entity 2 (B, C, D, E), FASTA

>9HNR_2 Gamma-aminobutyric acid receptor subunit beta-3,Green fluorescent protein (chains B, C, D, E)
MWGLAGGRLFGIFSAPVLVAVVCCAQSVNDPGNMSFVKETVDKLLKGYDIRLRPDFGGPP
VCVGMNIDIASIDMVSEVNMDYTLTMYFQQYWRDKRLAYSGIPLNLTLDNRVADQLWVPD
TYFLNDKKSFVHGVTVKNRMIRLHPDGTVLYGLRITTTAACMMDLRRYPLDEQNCTLEIE
SYGYTTDDIEFYWRGGDKAVTGVERIELPQFSIVEHRLVSRNVVFATGAYPRLSLSFRLK
RNIGYFILQTYMPSILITILSWVSFWINYDASAARVALGITTVLTMTTINTHLRETLPKI
PYVKAIDMYLMGCFVFVFLALLEYAFVNYIFFSQPGRAMVSKGEELFTGVVPILVEMDGD
VNGRKFSVRGVGEGDATHGKLTLKFICTSGKLPVPWPTLVTTLSYGVQCFSRYPDHMKQH
DFFKSAMPEGYVQERTIFFKDDGSYKTRAEVKFEGDTLVNRIVLKGTDFKEDGNILGHKL
EYNMNVGNVYITADKQKNGIKANFEIRHNVEDGGVQLADHYQQNTPIGDGSVLLPDNHYL
SVQVKLSKDPNEKRDHMVLLEFRTAAGITPGMDELYKGRAAAIDRWSRIVFPFTFSLFNL
VYWLYYVNSRENLYFQAHHHHHH

Sequence of entity 3 (P, Q, R), FASTA

>9HNR_3 Megabody 25 (chains P, Q, R)
MKKIWLALAGLVLAFSASAQVQLVESGGGLVQTKTTTSVIDTTNDAQNLLTQAQTIVNTL
KDYCPILIAKSSSSNGGTNNANTPSWQTAGGGKNSCATFGAEFSAASDMINNAQKIVQET
QQLSANQPKNITQPHNLNLNSPSSLTALAQKMLKNAQSQAEILKLANQVESDFNKLSSGH
LKDYIGKCDASAISSANMTMQNQKNNWGNGCAGVEETQSLLKTSAADFNNQTPQINQAQN
LANTLIQELGNNTYEQLSRLLTNDNGTNSKTSAQAINQAVNNLNERAKTLAGGTTNSPAY
QATLLALRSVLGLWNSMGYAVICGGYTKSPGENNQKDFHYTDENGNGTTINCGGSTNSNG
THSYNGTNTLKADKNVSLSIEQYEKIHEAYQILSKALKQAGLAPLNSKGEKLEAHVTTSK
YGSLRLSCAASGHTFNYPIMGWFRQAPGKEREFVGAISWSGGSTSYADSVKDRFTISRDN
AKNTVYLEMNNLKPEDTAVYYCAAKGRYSGGLYYPTNYDYWGQGTQVTVSSHHHHHHEPE
A

Ligands and cofactors

ID	Name	Formula	Copies
ABU	Gamma-amino-butanoic acid	C4 H9 N O2	1

Water and common crystallization additives (EPE) are not listed.

Primary citation

a5b3 GABAA Receptor in 1 a5 to 4 b3 stoichiometry in desensitized state. Cowgill, J., Fan, C., Howard, R.J. et al. To be published.

Other PDB entries of the same protein (UniProt P31644 (AlphaFold model), which also has an AlphaFold model), best resolution first:

8BHG 2.39 Å, GABA-A receptor a5 heteromer - a5V2 - Bretazenil
8BHB 2.54 Å, GABA-A receptor a5 homomer - a5V3 - RO154513
8BGI 2.56 Å, GABA-A receptor a5 homomer - a5V1 - Flumazenil
8BHA 2.67 Å, GABA-A receptor a5 homomer - a5V3 - Basmisanil - HR
8BHI 2.67 Å, GABA-A receptor a5 homomer - a5V3 - RO5211223
8BHO 2.93 Å, GABA-A receptor a5 homomer - a5V3 - L655708
8BHM 2.95 Å, GABA-A receptor a5 homomer - a5V3 - DMCM
9HNS 3.1 Å, a5b3 GABAAR bound to GABA and Mb25 in a desensitized state in saposin nanodiscs after…
9RL5 3.1 Å, a5b3 GABAAR bound to Topiramate, GABA, and Mb25 in a desensitized state in saposin…
9RPB 3.1 Å, a5b3 GABAAR bound to GABA, and Mb25 in a desensitized state in saposin nanodiscs,…
9HAA 3.14 Å, a5b3 GABAA Receptor resting state
5O8F 3.2 Å, Structure of a chimaeric beta3-alpha5 GABAA receptor in complex with nanobody Nb25 and…

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