9P9B: Activated GluA4 homotetrameric AMPAR

Activated GluA4 homotetrameric AMPAR. Determined by electron microscopy at 3.31 Å resolution. Released 28 Jan 2026.

Method: Electron microscopy
Resolution: 3.31 Å
Organisms: Rattus norvegicus, Mus musculus
Chains: 8
Atoms: 18,100
Mol. weight: 474.97 kDa
Ligands: CYZ, GLU
Released: 28 Jan 2026

Explore 9P9B in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9P9B contains 113 α-helices and 101 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: 21 helices, 20 β-strands

Element	Residues	Length	Sheet
β-strand	417-421	5	1
β-strand	429-430	2	2
β-strand	443-444	2	2
α-helix	446-458	13
β-strand	462-466	5	1
α-helix	467	1
β-strand	475	1	3
β-strand	482	1	3
α-helix	484-490	7
β-strand	496	1	1
β-strand	497	1	4
β-strand	502	1	5
α-helix	507-509	3
β-strand	511-513	3	4
α-helix	514	1
α-helix	516	1
β-strand	518-520	3	5
β-strand	522-527	6	6
α-helix	528-530	3
α-helix	538-540	3
β-strand	543	1	7
α-helix	545-567	23
α-helix	596-606	11
α-helix	618-642	25
α-helix	658-661	4
β-strand	668-671	4	6
β-strand	672	1	8
α-helix	676-683	8
α-helix	687-698	12
β-strand	705	1	8
α-helix	708-718	11
β-strand	722-727	6	6
α-helix	728-736	9
β-strand	742-745	4	6
β-strand	752-754	3	5
β-strand	757-759	3	4
α-helix	765-777	13
α-helix	780-786	7
α-helix	787-791	5
α-helix	811-813	3
α-helix	815-839	25

Chain B: 27 helices, 24 β-strands

Element	Residues	Length	Sheet
β-strand	417-421	5	9
β-strand	424	1	10
β-strand	428	1	10
β-strand	429-430	2	11
α-helix	434-436	3
α-helix	439-442	4
β-strand	443-444	2	11
α-helix	446-458	13
β-strand	462-466	5	9
β-strand	475	1	12
α-helix	481	1
β-strand	482	1	12
α-helix	483	1
α-helix	484-490	7
β-strand	496-497	2	9
β-strand	502	1	13
α-helix	505-508	4
β-strand	511-513	3	9
α-helix	514	1
α-helix	516	1
β-strand	518-520	3	13
β-strand	522-527	6	14
α-helix	528-531	4
β-strand	532	1	15
α-helix	533-535	3
α-helix	536-540	5
β-strand	543	1	16
α-helix	545-567	23
α-helix	596-606	11
α-helix	618-645	28
β-strand	650	1	15
α-helix	658-663	6
β-strand	668-670	3	14
β-strand	671-672	2	17
α-helix	676-683	8
α-helix	687-698	12
β-strand	704-705	2	17
α-helix	708-717	10
β-strand	722-727	6	14
α-helix	728-734	7
β-strand	742-745	4	14
β-strand	752-754	3	13
β-strand	757-759	3	9
α-helix	765-777	13
α-helix	780-788	9
α-helix	790-792	3
α-helix	808	1
β-strand	809	1	7
α-helix	810	1
α-helix	811-813	3
α-helix	815-838	24

Chain C: 23 helices, 17 β-strands

Element	Residues	Length	Sheet
β-strand	417-421	5	18
β-strand	424	1	19
β-strand	428	1	19
α-helix	434-436	3
α-helix	439-442	4
α-helix	446-458	13
β-strand	462-466	5	18
β-strand	475	1	20
α-helix	481	1
β-strand	482	1	20
α-helix	483	1
α-helix	484-490	7
β-strand	496-497	2	18
β-strand	502	1	18
α-helix	505-508	4
β-strand	511-520	10	18
β-strand	522-527	6	21
α-helix	528-531	4
α-helix	538-540	3
α-helix	545-565	21
α-helix	596-606	11
α-helix	618-642	25
α-helix	649-651	3
α-helix	659-662	4
β-strand	668-670	3	21
β-strand	671-672	2	22
α-helix	676-681	6
α-helix	687-696	10
β-strand	704-705	2	22
α-helix	708-717	10
β-strand	722-727	6	21
α-helix	728-735	8
β-strand	742-745	4	21
β-strand	752-759	8	18
α-helix	765-777	13
α-helix	780-788	9
α-helix	804-806	3
β-strand	809	1	16
α-helix	811-813	3
α-helix	815-838	24

Chain D: 21 helices, 20 β-strands

Element	Residues	Length	Sheet
β-strand	417-421	5	23
β-strand	429-430	2	24
α-helix	434-436	3
α-helix	440-442	3
β-strand	443-444	2	24
α-helix	446-458	13
β-strand	462-466	5	23
β-strand	475	1	25
β-strand	482	1	25
α-helix	484-490	7
β-strand	496-497	2	23
β-strand	502	1	23
α-helix	505-508	4
β-strand	511-520	10	23
β-strand	522	1	26
β-strand	524-527	4	27
α-helix	528-531	4
β-strand	532	1	28
α-helix	533-535	3
α-helix	536-540	5
α-helix	545-567	23
α-helix	596-606	11
α-helix	618-639	22
β-strand	650	1	28
α-helix	658-662	5
β-strand	668-670	3	27
β-strand	672	1	29
α-helix	676-683	8
α-helix	687-698	12
β-strand	705	1	29
α-helix	708-717	10
β-strand	722-724	3	27
β-strand	727	1	26
α-helix	728-734	7
β-strand	742-745	4	27
β-strand	752-759	8	23
α-helix	765-777	13
α-helix	780-788	9
α-helix	797-802	6
α-helix	811-813	3
α-helix	815-839	25

Chain E: 5 helices, 5 β-strands

Element	Residues	Length	Sheet
α-helix	9-28	20
β-strand	34-38	5	33
β-strand	57-61	5	33
β-strand	65-68	4	33
β-strand	78-79	2	33
α-helix	95-104	10
α-helix	106-122	17
α-helix	133-158	26
β-strand	175-176	2	33
α-helix	178-209	32

Chain F: 6 helices, 5 β-strands

Element	Residues	Length	Sheet
α-helix	8-29	22
β-strand	34-38	5	31
β-strand	57-61	5	31
β-strand	65-68	4	31
β-strand	77-79	3	31
α-helix	95-104	10
α-helix	106-127	22
α-helix	133-159	27
β-strand	175-176	2	31
α-helix	178-206	29
α-helix	207-209	3

Chain G: 5 helices, 5 β-strands

Element	Residues	Length	Sheet
α-helix	9-29	21
β-strand	34-37	4	32
β-strand	58-61	4	32
β-strand	65-68	4	32
β-strand	77-79	3	32
α-helix	96-104	9
α-helix	106-124	19
α-helix	133-159	27
β-strand	175-176	2	32
α-helix	178-209	32

Chain H: 5 helices, 5 β-strands

Element	Residues	Length	Sheet
α-helix	8-28	21
β-strand	34-36	3	30
β-strand	58-61	4	30
β-strand	65-69	5	30
β-strand	77-79	3	30
α-helix	95-104	10
α-helix	106-124	19
α-helix	133-159	27
β-strand	175-176	2	30
α-helix	178-209	32

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Isoform 2 of Glutamate receptor 4	A, B, C, D	protein	846	Rattus norvegicus	P19493 (AlphaFold model)
Voltage-dependent calcium channel gamma-2 subunit	E, F, G, H	protein	209	Mus musculus	O88602 (AlphaFold model)

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

>9P9B_1 Isoform 2 of Glutamate receptor 4 (chains A, B, C, D)
MGKIMHISVLLSPVLWGLIFGVSSVQIGGLFIRNTDQEYTAFRLAIFLHNTSPNASEAPF
NLVPHVDNIETANSFAVTNAFCSQYSRGVFAIFGLYDKRSVHTLTSFCSALHISLITPSF
PTEGESQFVLQLRPSLRGALLSLLDHYEWNCFVFLYDTDRGYSILQAIMEKAGQNGWHVS
AICVENFNDVSYRQLLEELDRRQEKKFVIDCEIERLQNILEQIVSVGKHVKGYHYIIANL
GFKDISLERFIHGGANVTGFQLVDFNTPMVTKLMDRWKKLDQREYPGSETPPKYTSALTY
DGVLVMAETFRSLRRQKIDISRRGNAGDCLANPAAPWGQGIDMERTLKQVRIQGLTGNVQ
FDHYGRRVNYTMDVFELKSTGPRKVGYWNDMDKLVLIQDMPTLGNDTAAIENRTVVVTTI
MESPYVMYKKNHEMFEGNDKYEGYCVDLASEIAKHIGIKYKIAIVPDGKYGARDADTKIW
NGMVGELVYGKAEIAIAPLTITLVREEVIDFSKPFMSLGISIMIKKPQKSKPGVFSFLDP
LAYEIWMCIVFAYIGVSVVLFLVSRFSPYEWHTEEPEDGKEGPSDQPPNEFGIFNSLWFS
LGAFMQQGCDISPRSLSGRIVGGVWWFFTLIIISSYTANLAAFLTVERMVSPIESAEDLA
KQTEIAYGTLDSGSTKEFFRRSKIAVYEKMWTYMRSAEPSVFTRTTAEGVARVRKSKGKF
AFLLESTMNEYIEQRKPCDTMKVGGNLDSKGYGVATPKGSSLRTPVNLAVLKLSEAGVLD
KLKNKWWYDKGECGPKDSGSKDKTSALSLSNVAGVFYILVGGLGLAMLVALIEFCYKSRA
EAKRMK

Sequence of entity 2 (E, F, G, H), FASTA

>9P9B_2 Voltage-dependent calcium channel gamma-2 subunit (chains E, F, G, H)
GLFDRGVQMLLTTVGAFAAFSLMTIAVGTDYWLYSRGVCKTKSVSEDETSKKNEEVMTHS
GLWRTCCLEGNFKGLCKQIDHFPEDADYEADTAEYFLRAVRASSIFPILSVILLFMGGLC
IAASEFYKTRHNIILSAGIFFVSAGLSNIIGIIVYISANAGDPSKSDSKKNSYSYGWSFY
FGALSFIIAEMVGVLAVHMFIDRHKQLTG

Ligands and cofactors

ID	Name	Formula	Copies
CYZ	Cyclothiazide	C14 H16 Cl N3 O4 S2	4
GLU	Glutamic acid	C5 H9 N O4	4

Primary citation

Structural basis for activation and conformational plasticity of the GluA4 AMPA receptor. Hale, W.D., Wang, H., Huganir, R.L. et al. Nat Commun (2026) 17. DOI 10.1038/s41467-026-68953-9 · PubMed

Other PDB entries of the same protein (UniProt P19493 (AlphaFold model), which also has an AlphaFold model), best resolution first:

3FAS 1.4 Å, X-ray structure of iGluR4 flip ligand-binding core (S1S2) in complex with (S)-glutamate…
3EPE 1.85 Å, Crystal Structure of the GluR4 Ligand-Binding domain in complex with glutamate
3FAT 1.9 Å, X-ray structure of iGluR4 flip ligand-binding core (S1S2) in complex with (S)-AMPA at…
3KEI 1.9 Å, Crystal Structure of the GluA4 Ligand-Binding domain L651V mutant in complex with…
3KFM 2.2 Å, Crystal Structure of the GluA4 Ligand-Binding domain L651V mutant in complex with kainate
4GPA 2.25 Å, High resolution structure of the GluA4 N-terminal domain (NTD)
3EN3 2.43 Å, Crystal Structure of the GluR4 Ligand-Binding domain in complex with kainate
5FWX 2.5 Å, Crystal structure of the AMPA receptor GluA2/A4 N-terminal domain heterodimer
9QDN 2.71 Å, GluA4 in complex with TARP-2, resting state I, structure of TMD/LBD
9RMW 2.9 Å, GluA4 in complex with TARP-2, open state, structure of TMD/LBD domains
9RN7 3.1 Å, GluA4 in complex with TARP-2, Desensitized state, structure of TMD domain
9NR6 3.26 Å, The structure of Noelin 1 with cerebellar GluA1/A4-ATD

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