9FFS: Alpha1beta3 GABA(A) receptor

Cryo-EM structure of the alpha1beta3 GABA(A) receptor in complex with GABA and Mb25 in the short-lived asymmetric open state of branch 2. Determined by electron microscopy at 3.2 Å resolution. Released 4 Jun 2025.

Method: Electron microscopy
Resolution: 3.2 Å
Organisms: Homo sapiens, Lama glama, Helicobacter pylori G27
Chains: 6
Atoms: 14,930
Mol. weight: 293.38 kDa
Ligands: ABU
Released: 4 Jun 2025

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

Secondary structure: helices and β-sheets

9FFS contains 64 α-helices and 77 β-strands across 6 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, 14 β-strands

Element	Residues	Length	Sheet
α-helix	13-22	10
β-strand	39-54	16	9
β-strand	59-71	13	9
α-helix	73-75	3
β-strand	83-86	4	9
α-helix	88-93	6
β-strand	99-101	3	5
β-strand	104	1	9
β-strand	108-109	2	9
β-strand	117-122	6	9
β-strand	126-138	13	9
α-helix	143-145	3
β-strand	150-159	10	5
β-strand	167-171	5	9
α-helix	175-178	4
β-strand	179-181	3	9
β-strand	186	1	9
β-strand	191-205	15	5
β-strand	208-221	14	5
α-helix	224-226	3
α-helix	227-231	5
α-helix	232-243	12
α-helix	244-246	3
α-helix	252-272	21
α-helix	285-311	27
α-helix	386-416	31

Chain B: 14 helices, 13 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	81-83	3	6
α-helix	85-90	6
β-strand	96-98	3	7
β-strand	101-106	6	6
β-strand	110	1	8
β-strand	114-118	5	6
β-strand	123-135	13	6
β-strand	147-156	10	7
β-strand	164-168	5	6
α-helix	171-173	3
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	227-237	11
α-helix	238-241	4
α-helix	247-269	23
α-helix	278-279	2
α-helix	280-305	26
α-helix	310-446	30

Chain C: 12 helices, 13 β-strands

Element	Residues	Length	Sheet
α-helix	9-19	11
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	8
β-strand	101-106	6	10
β-strand	110	1	2
β-strand	114-118	5	10
β-strand	123-135	13	10
β-strand	147-156	10	8
β-strand	164-168	5	10
α-helix	171-173	3
β-strand	175-176	2	10
β-strand	186-200	15	8
β-strand	203-216	14	8
α-helix	219-221	3
α-helix	222-226	5
α-helix	227-236	10
α-helix	237-241	5
α-helix	247-269	23
α-helix	280-305	26
α-helix	310-445	29

Chain D: 11 helices, 14 β-strands

Element	Residues	Length	Sheet
α-helix	13-23	11
β-strand	39-54	16	1
β-strand	59-71	13	1
α-helix	73-75	3
β-strand	83-86	4	1
α-helix	88-93	6
β-strand	99-101	3	2
β-strand	104	1	1
β-strand	108-109	2	1
β-strand	117-122	6	1
β-strand	126-138	13	1
β-strand	150-159	10	2
β-strand	167-171	5	1
α-helix	175-177	3
β-strand	179-181	3	1
β-strand	186	1	1
β-strand	191-205	15	2
β-strand	208-221	14	2
α-helix	224-226	3
α-helix	227-231	5
α-helix	232-243	12
α-helix	244-246	3
α-helix	252-273	22
α-helix	285-309	25
α-helix	386-416	31

Chain E: 13 helices, 13 β-strands

Element	Residues	Length	Sheet
α-helix	9-19	11
α-helix	35	1
β-strand	36-51	16	3
β-strand	56-68	13	3
α-helix	70-72	3
β-strand	81-83	3	3
α-helix	85-89	5
β-strand	96-98	3	4
β-strand	101-106	6	3
β-strand	110	1	5
β-strand	114-118	5	3
β-strand	123-135	13	3
β-strand	147-156	10	4
β-strand	164-168	5	3
α-helix	171-173	3
β-strand	175-176	2	3
α-helix	178-180	3
β-strand	186-200	15	4
β-strand	203-216	14	4
α-helix	219-221	3
α-helix	222-226	5
α-helix	227-236	10
α-helix	237-241	5
α-helix	247-269	23
α-helix	280-304	25
α-helix	310-445	29

Chain F: 2 helices, 10 β-strands

Element	Residues	Length	Sheet
β-strand	3-8	6	11
β-strand	407-414	8	11
β-strand	421-427	7	12
β-strand	433-440	8	12
β-strand	447-448	2	12
α-helix	450-452	3
β-strand	456-461	6	11
β-strand	466-471	6	11
β-strand	481-487	7	12
α-helix	497-499	3
β-strand	500-503	4	12
β-strand	507-508	2	12

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Gamma-aminobutyric acid receptor subunit alpha-1	A, D	protein	411	Homo sapiens	P14867 (AlphaFold model)
Gamma-aminobutyric acid receptor subunit beta-3	B, C, E	protein	395	Homo sapiens	P28472 (AlphaFold model)
Megabody25,Outer membrane protein	F	protein	522	Lama glama, Helicobacter pylori G27	B5Z8H1 (AlphaFold model)

Sequence of entity 1 (A, D), FASTA

>9FFS_1 Gamma-aminobutyric acid receptor subunit alpha-1 (chains A, D)
MDEKTTGWRGGHVVEGLAGELEQLRARLEHHPQGQREPDYDIPTTENLYFQGTGQPSQDE
LKDNTTVFTRILDRLLDGYDNRLRPGLGERVTEVKTDIFVTSFGPVSDHDMEYTIDVFFR
QSWKDERLKFKGPMTVLRLNNLMASKIWTPDTFFHNGKKSVAHNMTMPNKLLRITEDGTL
LYTMRLTVRAECPMHLEDFPMDAHACPLKFGSYAYTRAEVVYEWTREPARSVVVAEDGSR
LNQYDLLGQTVDSGIVQSSTGEYVVMTTHFHLKRKIGYFVIQTYLPCIMTVILSQVSFWL
NRESVPARTVFGVTTVLTMTTLSISARNSLPKVAYATAMDWFIAVCYAFVFSALIEFATV
NYFTKSQPARAAKIDRLSRIAFPLLFGIFNLVYWATYLNREPQLKAPTPHQ

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

>9FFS_2 Gamma-aminobutyric acid receptor subunit beta-3 (chains B, C, E)
MDEKTTGWRGGHVVEGLAGELEQLRARLEHHPQGQREPDYDIPTTENLYFQGTGQSVNDP
GNMSFVKETVDKLLKGYDIRLRPDFGGPPVCVGMNIDIASIDMVSEVNMDYTLTMYFQQY
WRDKRLAYSGIPLNLTLDNRVADQLWVPDTYFLNDKKSFVHGVTVKNRMIRLHPDGTVLY
GLRITTTAACMMDLRRYPLDEQNCTLEIESYGYTTDDIEFYWRGGDKAVTGVERIELPQF
SIVEHRLVSRNVVFATGAYPRLSLSFRLKRNIGYFILQTYMPSILITILSWVSFWINYDA
SAARVALGITTVLTMTTINTHLRETLPKIPYVKAIDMYLMGCFVFVFLALLEYAFVNYIF
FSQPARAAAIDRWSRIVFPFTFSLFNLVYWLYYVN

Sequence of entity 3 (F), FASTA

>9FFS_3 Megabody25,Outer membrane protein (chains F)
QVQLVESGGGLVQTKTTTSVIDTTNDAQNLLTQAQTIVNTLKDYCPILIAKSSSSNGGTN
NANTPSWQTAGGGKNSCATFGAEFSAASDMINNAQKIVQETQQLSANQPKNITQPHNLNL
NSPSSLTALAQKMLKNAQSQAEILKLANQVESDFNKLSSGHLKDYIGKCDASAISSANMT
MQNQKNNWGNGCAGVEETQSLLKTSAADFNNQTPQINQAQNLANTLIQELGNNTYEQLSR
LLTNDNGTNSKTSAQAINQAVNNLNERAKTLAGGTTNSPAYQATLLALRSVLGLWNSMGY
AVICGGYTKSPGENNQKDFHYTDENGNGTTINCGGSTNSNGTHSYNGTNTLKADKNVSLS
IEQYEKIHEAYQILSKALKQAGLAPLNSKGEKLEAHVTTSKYGSLRLSCAASGHTFNYPI
MGWFRQAPGKEREFVGAISWSGGSTSYADSVKDRFTISRDNAKNTVYLEMNNLKPEDTAV
YYCAAKGRYSGGLYYPTNYDYWGQGTQVTVSSHHHHHHEPEA

Ligands and cofactors

ID	Name	Formula	Copies
ABU	Gamma-amino-butanoic acid	C4 H9 N O2	2

Primary citation

Cryo-EM structure of the alpha1beta3 GABA(A) receptor in complex with GABA and Mb25 in the short-lived asymmetric open state of branch 2. Mihaylov, D.B., Malinauskas, T., Aricescu, A.R. To be published.

Other PDB entries of the same protein (UniProt P14867 (AlphaFold model), which also has an AlphaFold model), best resolution first:

9RGD 2.0 Å, CryoEM structure of human alpha1beta3gamma2L GABA(A)R in CL47a
9EQG 2.4 Å, CryoEM structure of human full-length alpha1beta3gamma2L GABA(A)R in complex with GABA…
9FAS 2.5 Å, CryoEM structure of human full-length alpha1beta3gamma2L GABA(A)R in complex with…
9FFU 2.5 Å, Cryo-EM structure of the alpha1beta3 GABA(A) receptor in complex with GABA and Mb25 in…
6X3T 2.55 Å, Human GABAA receptor alpha1-beta2-gamma2 subtype in complex with GABA plus propofol
8VRN 2.57 Å, Human GABAA receptor alpha1-beta2-gamma2 subtype in complex with GABA plus PPTQ
8PET 2.6 Å, Cryo-EM structure of the full-length human alpha1beta3 GABA(A) receptor (babba…
9FAJ 2.6 Å, CryoEM structure of human full-length alpha1beta3gamma2 GABA(A) receptor in complex with…
9FAK 2.6 Å, CryoEM structure of human full-length alpha1beta3gamma2 GABA(A) receptor in complex with…
9FGG 2.6 Å, Cryo-EM structure of the full-length alpha1beta3gamma2 GABA(A) receptor in Saposin A…
8SGO 2.65 Å, Human GABAA receptor alpha1-beta2-gamma2 subtype in complex with GABA plus pregnenolone…
7QNE 2.7 Å, Cryo-EM structure of human full-length synaptic alpha1beta3gamma2 GABA(A)R in complex…

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