9MBB: Antagonist-bound GPCR

Cryo-EM structure of antagonist-bound GPCR. Determined by electron microscopy at 3.25 Å resolution. Released 1 Oct 2025.

Method: Electron microscopy
Resolution: 3.25 Å
Organism: Homo sapiens
Chains: 2
Atoms: 11,998
Mol. weight: 204.42 kDa
Ligands: Z99
Released: 1 Oct 2025

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

Secondary structure: helices and β-sheets

9MBB contains 70 α-helices and 56 β-strands across 2 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.

Chains A and B: 35 helices, 28 β-strands

Element	Residues	Length	Sheet
β-strand	40-42	3	1
β-strand	46-52	7	1
β-strand	56	1	2
β-strand	64	1	2
α-helix	73-86	14
β-strand	98-104	7	1
α-helix	109-119	11
α-helix	141-145	5
β-strand	147-151	5	1
α-helix	159-167	9
β-strand	173-175	3	1
α-helix	181-183	3
β-strand	192-194	3	1
α-helix	199-201	3
α-helix	203-212	10
β-strand	217-222	6	3
α-helix	226-239	14
β-strand	246-252	7	3
α-helix	257-258	2
α-helix	261-269	9
β-strand	277-281	5	3
α-helix	284-293	10
β-strand	304-307	4	3
β-strand	328-333	6	3
α-helix	339-347	9
α-helix	360-367	8
α-helix	402-423	22
α-helix	432-435	4
α-helix	439-446	8
β-strand	451-452	2	4
β-strand	458-459	2	4
β-strand	470-479	10	3
β-strand	482-492	11	3
β-strand	495-497	3	3
α-helix	499-501	3
β-strand	524-528	5	5
α-helix	529	1
β-strand	536-540	5	5
β-strand	545	1	6
β-strand	555	1	6
α-helix	556-557	2
β-strand	561-562	2	7
α-helix	563	1
β-strand	569-570	2	7
α-helix	571-573	3
β-strand	574	1	8
α-helix	585-607	23
α-helix	615-618	4
α-helix	620-638	19
α-helix	642-643	2
α-helix	647-674	28
α-helix	675-677	3
α-helix	691-711	21
β-strand	722-723	2	9
β-strand	738	1	8
β-strand	740-741	2	9
α-helix	746-752	7
α-helix	754-771	18
α-helix	780-795	16
α-helix	797-802	6
α-helix	803-805	3
α-helix	810-829	20
α-helix	836-838	3

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Metabotropic glutamate receptor 8	A, B	protein	908	Homo sapiens	O00222 (AlphaFold model)

Sequence of entity 1 (A, B), FASTA

>9MBB_1 Metabotropic glutamate receptor 8 (chains A, B)
MVCEGKRSASCPCFFLLTAKFYWILTMMQRTHSQEYAHSIRVDGDIILGGLFPVHAKGER
GVPCGELKKEKGIHRLEAMLYAIDQINKDPDLLSNITLGVRILDTCSRDTYALEQSLTFV
QALIEKDASDVKCANGDPPIFTKPDKISGVIGAAASSVSIMVANILRLFKIPQISYASTA
PELSDNTRYDFFSRVVPPDSYQAQAMVDIVTALGWNYVSTLASEGNYGESGVEAFTQISR
EIGGVCIAQSQKIPREPRPGEFEKIIKRLLETPNARAVIMFANEDDIRRILEAAKKLNQS
GHFLWIGSDSWGSKIAPVYQQEEIAEGAVTILPKRASIDGFDRYFRSRTLANNRRNVWFA
EFWEENFGCKLGSHGKRNSHIKKCTGLERIARDSSYEQEGKVQFVIDAVYSMAYALHNMH
KDLCPGYIGLCPRMSTIDGKELLGYIRAVNFNGSAGTPVTFNENGDAPGRYDIFQYQITN
KSTEYKVIGHWTNQLHLKVEDMQWAHREHTHPASVCSLPCKPGERKKTVKGVPCCWHCER
CEGYNYQVDELSCELCPLDQRPNMNRTGCQLIPIIKLEWHSPWAVVPVFVAILGIIATTF
VIVTFVRYNDTPIVRASGRELSYVLLTGIFLCYSITFLMIAAPDTIICSFRRVFLGLGMC
FSYAALLTKTNRIHRIFEQGKKSVTAPKFISPASQLVITFSLISVQLLGVFVWFVVDPPH
IIIDYGEQRTLDPEKARGVLKCDISDLSLICSLGYSILLMVTCTVYAIKTRGVPETFNEA
KPIGFTMYTTCIIWLAFIPIFFGTAQSAEKMYIQTTTLTVSMSLSASVSLGMLYMPKVYI
IIFHPEQNVQKRKRSFKAVVTAATMQSKLIQKGNDRPNGEVKSELCESLETNTSSTKTTY
ISYSNHSI

Ligands and cofactors

ID	Name	Formula	Copies
Z99	2-[(1S,2S)-2-carboxycyclopropyl]-3-(9H-xanthen-9-yl)-D-alanine	C20 H19 N O5	2

Primary citation

Structural characterization of five functional states of metabotropic glutamate receptor 8. Zhao, J., Deng, Y., Xu, Z. et al. Mol Cell (2025) 85:3460-3473.e6. DOI 10.1016/j.molcel.2025.08.019 · PubMed

Other PDB entries of the same protein (UniProt O00222 (AlphaFold model), which also has an AlphaFold model), best resolution first:

6BSZ 2.65 Å, Human mGlu8 Receptor complexed with glutamate
9N8Y 2.76 Å, Cryo EM Structure of Full Length mGluR8 Bound to Agonist L-AP4 and PAM VU6005649
6BT5 2.92 Å, Human mGlu8 Receptor complexed with L-AP4
6E5V 2.95 Å, human mGlu8 receptor amino terminal domain in complex with…
9MB9 2.97 Å, Cryo-EM structure of Gi-bound GPCR
9MBC 2.97 Å, Cryo-EM structure of agonist-bound GPCR
9N8Z 2.97 Å, Cryo EM Structure of Full Length mGluR8 Bound to Agonist L-AP4 and PAM VU6005649, class 2
9MBA 3.14 Å, Cryo-EM structure of complex of transducer-bound GPCR
9MBD 3.32 Å, Cryo-EM structure of Apo-GPCR
9Y1M 3.32 Å, Cryo EM Structure of Full Length mGluR8 in Complex with Beta-Arrestin-1 Bound to Agonist…
9Y1N 6.18 Å, Cryo EM Structure of Full lengthmGluR8 Bound to Agonist L-AP4 and PAM VU6005649 in…

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