9MB9: Gi-bound GPCR

Cryo-EM structure of Gi-bound GPCR. Determined by electron microscopy at 2.97 Å resolution. Released 1 Oct 2025.

Method: Electron microscopy
Resolution: 2.97 Å
Organism: Homo sapiens
Chains: 5
Atoms: 16,838
Mol. weight: 290.4 kDa
Ligands: HVG, A1ENS
Released: 1 Oct 2025

Explore 9MB9 in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9MB9 contains 75 α-helices and 98 β-strands across 5 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: 9 helices, 11 β-strands

Element	Residues	Length	Sheet
α-helix	7-30	24
β-strand	34	1	19
β-strand	36-40	5	20
α-helix	46-53	8
β-strand	185-186	2	20
β-strand	189-190	2	19
β-strand	195-196	2	19
β-strand	199-200	2	20
α-helix	208-211	4
α-helix	212-215	4
β-strand	220-224	5	20
β-strand	233	1	21
β-strand	241	1	21
α-helix	242-254	13
β-strand	264-268	5	20
α-helix	271-277	7
α-helix	283-285	3
α-helix	296-307	12
β-strand	319-323	5	20
α-helix	331-350	20

Chain B: 3 helices, 28 β-strands

Element	Residues	Length	Sheet
α-helix	2-23	22
α-helix	30-33	4
α-helix	39-43	5
β-strand	47-51	5	22
β-strand	58-63	6	23
β-strand	69-74	6	23
β-strand	78-83	6	23
β-strand	89-94	6	23
β-strand	102-105	4	24
β-strand	111-115	5	24
β-strand	120-125	6	24
β-strand	134-140	7	24
β-strand	146-151	6	25
β-strand	156-161	6	25
β-strand	165-170	6	25
β-strand	175-181	7	25
β-strand	187-192	6	26
β-strand	198-203	6	26
β-strand	207-212	6	26
β-strand	218-223	6	26
β-strand	229-234	6	27
β-strand	240-245	6	27
β-strand	250-254	5	27
β-strand	259-264	6	27
β-strand	273-278	6	28
β-strand	284-289	6	28
β-strand	294-298	5	28
β-strand	304-308	5	28
β-strand	315-319	5	22
β-strand	327-331	5	22
β-strand	336-339	4	22

Chain C: 5 helices, 0 β-strands

Element	Residues	Length
α-helix	7-22	16
α-helix	27-29	3
α-helix	30-38	9
α-helix	40-43	4
α-helix	53-55	3

Chain D: 28 helices, 29 β-strands

Element	Residues	Length	Sheet
β-strand	40-42	3	1
β-strand	46-52	7	1
β-strand	55-57	3	2
β-strand	64-67	4	2
α-helix	69-74	6
α-helix	75-88	14
β-strand	98-104	7	1
α-helix	109-119	11
β-strand	147-151	5	1
α-helix	156-169	14
β-strand	173-175	3	1
α-helix	181-184	4
β-strand	192-194	3	1
α-helix	199-212	14
β-strand	217-223	7	3
α-helix	226-242	17
β-strand	246-253	8	3
α-helix	257-258	2
α-helix	261-269	9
β-strand	277-281	5	3
α-helix	284-296	13
β-strand	304-307	4	3
α-helix	315-318	4
β-strand	329-333	5	3
α-helix	339-347	9
α-helix	359-366	8
β-strand	370	1	4
β-strand	383	1	4
α-helix	402-422	21
α-helix	439-447	9
β-strand	450-452	3	5
β-strand	458-460	3	5
β-strand	471-478	8	3
β-strand	483-491	9	3
β-strand	495-497	3	3
α-helix	518-521	4
β-strand	527	1	6
α-helix	528-529	2
β-strand	537	1	6
β-strand	545-546	2	7
β-strand	554-555	2	7
β-strand	560-562	3	8
β-strand	569-571	3	8
α-helix	572-573	2
β-strand	574-575	2	9
α-helix	582-607	26
α-helix	612-616	5
α-helix	619-641	23
α-helix	646-680	35
α-helix	694-716	23
β-strand	722-724	3	9
α-helix	733-735	3
β-strand	738-741	4	9
α-helix	746-769	24
α-helix	780-803	24
α-helix	810-843	34
α-helix	845-847	3

Chain R: 30 helices, 30 β-strands

Element	Residues	Length	Sheet
β-strand	40-42	3	10
β-strand	46-52	7	10
β-strand	55-57	3	11
β-strand	64-67	4	11
α-helix	69-73	5
α-helix	74-87	14
β-strand	98-104	7	10
α-helix	109-119	11
β-strand	147-151	5	10
α-helix	156-169	14
β-strand	173-175	3	10
α-helix	181-184	4
β-strand	192-194	3	10
α-helix	199-213	15
β-strand	217-222	6	12
β-strand	223	1	13
α-helix	226-242	17
β-strand	246-250	5	12
β-strand	253	1	13
α-helix	261-270	10
β-strand	277-281	5	12
α-helix	284-296	13
β-strand	304-307	4	12
α-helix	316-318	3
β-strand	329-333	5	12
α-helix	339-346	8
α-helix	359-367	9
α-helix	402-422	21
α-helix	437-438	2
α-helix	439-447	9
β-strand	451-452	2	14
β-strand	458-459	2	14
β-strand	466	1	10
β-strand	470-478	9	12
β-strand	483-492	10	12
β-strand	495-497	3	12
α-helix	518-521	4
β-strand	524-529	6	15
β-strand	532-540	9	15
β-strand	545-547	3	16
β-strand	553-555	3	16
β-strand	562	1	17
β-strand	569	1	17
β-strand	574-575	2	18
α-helix	582-607	26
α-helix	612-615	4
α-helix	619-640	22
α-helix	642-643	2
α-helix	645-654	10
α-helix	657-679	23
α-helix	686-687	2
α-helix	692-716	25
β-strand	721-724	4	18
α-helix	733-735	3
β-strand	738-742	5	18
α-helix	746-752	7
α-helix	754-769	16
α-helix	780-802	23
α-helix	810-833	24
α-helix	835-843	9

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Metabotropic glutamate receptor 8	D, R	protein	908	Homo sapiens	O00222 (AlphaFold model)
Guanine nucleotide-binding protein G(i) subunit alpha-1	A	protein	354	Homo sapiens	P63096 (AlphaFold model)
Guanine nucleotide-binding protein G(I)/G(S)/G(T) subunit beta-1	B	protein	343	Homo sapiens	P62873 (AlphaFold model)
Guanine nucleotide-binding protein G(I)/G(S)/G(O) subunit gamma-2	C	protein	71	Homo sapiens	P59768 (AlphaFold model)

Sequence of entity 1 (D, R), FASTA

>9MB9_1 Metabotropic glutamate receptor 8 (chains D, R)
MVCEGKRSASCPCFFLLTAKFYWILTMMQRTHSQEYAHSIRVDGDIILGGLFPVHAKGER
GVPCGELKKEKGIHRLEAMLYAIDQINKDPDLLSNITLGVRILDTCSRDTYALEQSLTFV
QALIEKDASDVKCANGDPPIFTKPDKISGVIGAAASSVSIMVANILRLFKIPQISYASTA
PELSDNTRYDFFSRVVPPDSYQAQAMVDIVTALGWNYVSTLASEGNYGESGVEAFTQISR
EIGGVCIAQSQKIPREPRPGEFEKIIKRLLETPNARAVIMFANEDDIRRILEAAKKLNQS
GHFLWIGSDSWGSKIAPVYQQEEIAEGAVTILPKRASIDGFDRYFRSRTLANNRRNVWFA
EFWEENFGCKLGSHGKRNSHIKKCTGLERIARDSSYEQEGKVQFVIDAVYSMAYALHNMH
KDLCPGYIGLCPRMSTIDGKELLGYIRAVNFNGSAGTPVTFNENGDAPGRYDIFQYQITN
KSTEYKVIGHWTNQLHLKVEDMQWAHREHTHPASVCSLPCKPGERKKTVKGVPCCWHCER
CEGYNYQVDELSCELCPLDQRPNMNRTGCQLIPIIKLEWHSPWAVVPVFVAILGIIATTF
VIVTFVRYNDTPIVRASGRELSYVLLTGIFLCYSITFLMIAAPDTIICSFRRVFLGLGMC
FSYAALLTKTNRIHRIFEQGKKSVTAPKFISPASQLVITFSLISVQLLGVFVWFVVDPPH
IIIDYGEQRTLDPEKARGVLKCDISDLSLICSLGYSILLMVTCTVYAIKTRGVPETFNEA
KPIGFTMYTTCIIWLAFIPIFFGTAQSAEKMYIQTTTLTVSMSLSASVSLGMLYMPKVYI
IIFHPEQNVQKRKRSFKAVVTAATMQSKLIQKGNDRPNGEVKSELCESLETNTSSTKTTY
ISYSNHSI

Sequence of entity 2 (A), FASTA

>9MB9_2 Guanine nucleotide-binding protein G(i) subunit alpha-1 (chains A)
MGCTLSAEDKAAVERSKMIDRNLREDGEKAAREVKLLLLGAGESGKNTIVKQMKIIHEAG
YSEEECKQYKAVVYSNTIQSIIAIIRAMGRLKIDFGDSARADDARQLFVLAGAAEEGFMT
AELAGVIKRLWKDSGVQACFNRSREYQLNDSAAYYLNDLDRIAQPNYIPTQQDVLRTRVK
TTGIVETHFTFKDLHFKMFDVGAQRSERKKWIHCFEGVTAIIFCVALSDYDLVLAEDEEM
NRMHASMKLFDSICNNKWFTDTSIILFLNKKDLFEEKIKKSPLTICYPEYAGSNTYEEAA
AYIQCQFEDLNKRKDTKEIYTHFTCSTDTKNVQFVFDAVTDVIIKNNLKDCGLF

Sequence of entity 3 (B), FASTA

>9MB9_3 Guanine nucleotide-binding protein G(I)/G(S)/G(T) subunit beta-1 (chains B)
GSSGSELDQLRQEAEQLKNQIRDARKACADATLSQITNNIDPVGRIQMRTRRTLRGHLAK
IYAMHWGTDSRLLVSASQDGKLIIWDSYTTNKVHAIPLRSSWVMTCAYAPSGNYVACGGL
DNICSIYNLKTREGNVRVSRELAGHTGYLSCCRFLDDNQIVTSSGDTTCALWDIETGQQT
TTFTGHTGDVMSLSLAPDTRLFVSGACDASAKLWDVREGMCRQTFTGHESDINAICFFPN
GNAFATGSDDATCRLFDLRADQELMTYSHDNIICGITSVSFSKSGRLLLAGYDDFNCNVW
DALKADRAGVLAGHDNRVSCLGVTDDGMAVATGSWDSFLKIWN

Sequence of entity 4 (C), FASTA

>9MB9_4 Guanine nucleotide-binding protein G(I)/G(S)/G(O) subunit gamma-2 (chains C)
MASNNTASIAQARKLVEQLKMEANIDRIKVSKAAADLMAYCEAHAKEDPLLTPVPASENP
FREKKFFCAIL

Ligands and cofactors

ID	Name	Formula	Copies
HVG	4-[(S)-amino(carboxy)methyl]benzene-1,2-dicarboxylic acid	C10 H9 N O6	2
A1ENS	~{N}-[3-chloranyl-4-(5-chloranylpyridin-2-yl)oxy-phenyl]pyridine-2-carboxamide	C17 H11 Cl2 N3 O2	1

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…
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
9MBB 3.25 Å, Cryo-EM structure of antagonist-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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