24XB: Apo FFAR4-Gq Complex

Cryo-EM Structure of the Apo FFAR4-Gq Complex. Determined by electron microscopy at 2.65 Å resolution. Released 8 Jul 2026.

Method: Electron microscopy
Resolution: 2.65 Å
Organism: Homo sapiens
Chains: 5
Atoms: 8,837
Mol. weight: 153.17 kDa
Released: 8 Jul 2026

Explore 24XB in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

24XB contains 32 α-helices and 68 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: 12 helices, 4 β-strands

Element	Residues	Length	Sheet
α-helix	39-65	27
α-helix	77-101	25
α-helix	110-141	32
α-helix	154-169	16
α-helix	172-175	4
β-strand	179	1	16
β-strand	182	1	17
β-strand	191	1	17
β-strand	194	1	16
α-helix	201-212	12
α-helix	213-217	5
α-helix	218-243	26
α-helix	249-276	28
α-helix	278-292	15
α-helix	300-311	12
α-helix	313-322	10

Chain B: 3 helices, 28 β-strands

Element	Residues	Length	Sheet
α-helix	9-24	16
α-helix	30-33	4
α-helix	38-39	2
β-strand	47-51	5	1
β-strand	58-63	6	2
β-strand	69-74	6	2
β-strand	78-83	6	2
β-strand	89-94	6	2
β-strand	100-105	6	3
β-strand	111-116	6	3
β-strand	121-125	5	3
β-strand	134-139	6	3
β-strand	146-151	6	4
β-strand	157-161	5	4
β-strand	166-168	3	4
β-strand	178-180	3	4
β-strand	187-192	6	5
β-strand	198-203	6	5
β-strand	208-212	5	5
β-strand	218-222	5	5
β-strand	229-234	6	6
β-strand	240-245	6	6
β-strand	252-254	3	6
β-strand	260-262	3	6
β-strand	273-278	6	7
β-strand	284-289	6	7
β-strand	296-298	3	7
β-strand	303-306	4	7
β-strand	319-320	2	1
β-strand	327-329	3	1
β-strand	336-339	4	1

Chain C: 3 helices, 0 β-strands

Element	Residues	Length
α-helix	11-23	13
α-helix	30-43	14
α-helix	53-55	3

Chain D: 5 helices, 29 β-strands

Element	Residues	Length	Sheet
β-strand	20	1	8
β-strand	23-24	2	9
β-strand	27-29	3	10
β-strand	33-40	8	9
β-strand	42	1	8
α-helix	46-48	3
β-strand	50-52	3	11
β-strand	55-56	2	10
β-strand	62-63	2	10
β-strand	66-68	3	11
β-strand	75-77	3	11
α-helix	79-81	3
β-strand	85-90	6	9
β-strand	95-103	9	9
β-strand	109-111	3	10
β-strand	114-116	3	11
β-strand	127-128	2	11
β-strand	132-136	5	10
α-helix	154-156	3
β-strand	157-158	2	12
β-strand	163	1	13
β-strand	173-178	6	12
β-strand	183	1	14
β-strand	189	1	14
β-strand	191-196	6	13
β-strand	202-207	6	13
β-strand	211-212	2	13
α-helix	213	1
β-strand	220-224	5	12
β-strand	228-233	6	12
β-strand	243-248	6	13
α-helix	254	1
β-strand	256	1	13
β-strand	260-261	2	13

Chain E: 9 helices, 7 β-strands

Element	Residues	Length	Sheet
α-helix	7-29	23
β-strand	35-37	3	15
α-helix	46-56	11
β-strand	184-189	6	15
α-helix	193	1
β-strand	194-199	6	15
α-helix	207-209	3
α-helix	211-214	4
β-strand	219-220	2	15
β-strand	223-225	3	15
α-helix	243-246	4
β-strand	262-268	7	15
α-helix	270-276	7
α-helix	298-308	11
β-strand	318-323	6	15
α-helix	330-349	20

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Guanine nucleotide-binding protein G(I)/G(S)/G(T) subunit beta-1	B	protein	337	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)
scFv16	D	protein	247	Homo sapiens
Guanine nucleotide-binding protein G(q) subunit alpha	E	protein	353	Homo sapiens	P50148 (AlphaFold model)
Free fatty acid receptor 4	A	protein	361	Homo sapiens	Q5NUL3 (AlphaFold model)

Sequence of entity 1 (B), FASTA

>24XB_1 Guanine nucleotide-binding protein G(I)/G(S)/G(T) subunit beta-1 (chains B)
LDQLRQEAEQLKNQIRDARKACADATLSQITNNIDPVGRIQMRTRRTLRGHLAKIYAMHW
GTDSRLLVSASQDGKLIIWDSYTTNKVHAIPLRSSWVMTCAYAPSGNYVACGGLDNICSI
YNLKTREGNVRVSRELAGHTGYLSCCRFLDDNQIVTSSGDTTCALWDIETGQQTTTFTGH
TGDVMSLSLAPDTRLFVSGACDASAKLWDVREGMCRQTFTGHESDINAICFFPNGNAFAT
GSDDATCRLFDLRADQELMTYSHDNIICGITSVSFSKSGRLLLAGYDDFNCNVWDALKAD
RAGVLAGHDNRVSCLGVTDDGMAVATGSWDSFLKIWN

Sequence of entity 2 (C), FASTA

>24XB_2 Guanine nucleotide-binding protein G(I)/G(S)/G(O) subunit gamma-2 (chains C)
MASNNTASIAQARKLVEQLKMEANIDRIKVSKAAADLMAYCEAHAKEDPLLTPVPASENP
FFEKKFFCAIL

Sequence of entity 3 (D), FASTA

>24XB_3 scFv16 (chains D)
DVQLVESGGGLVQPGGSRKLSCSASGFAFSSFGMHWVRQAPEKGLEWVAYISSGSGTIYY
ADTVKGRFTISRDDPKNTLFLQMTSLRSEDTAMYYCVRSIYYYGSSPFDFWGQGTTLTVS
SGGGGSGGGGSGGGGSDIVMTQATSSVPVTPGESVSISCRSSKSLLHSNGNTYLYWFLQR
PGQSPQLLIYRMSNLASGVPDRFSGSGSGTAFTLTISRLEAEDVGVYYCMQHLEYPLTFG
AGTKLEL

Sequence of entity 4 (E), FASTA

>24XB_4 Guanine nucleotide-binding protein G(q) subunit alpha (chains E)
MGCTLSAEDKAAVERSKMIERQLRRDKRDARRELKLLLLGTGESGKSTFIKQMRIIHGSG
YSDEDKRGFTKLVYQNIFTAMQAMIRAMDTLKIPYKYEHNKAHAQLVREVDVEKVSAFEN
PYVDAIKSLWNDPGIQECYDRRREYQLSDSTKYYLNDLDRVADPAYLPTQQDVLRVRVPT
TGIIEYPFDLQSVIFRMVDVGGQRSERRKWIHCFENVTSIMFLVALSEYDQVLVESDNEN
RMEESKALFRTIITYPWFQNSSVILFLNKKDLLEEKIMYSHLVDYFPEYDGPQRDAQAAR
EFILKMFVDLNPDSDKIIYSHFTCATDTENIRFVFAAVKDTILQLNLKEYNLV

Sequence of entity 5 (A), FASTA

>24XB_5 Free fatty acid receptor 4 (chains A)
MSPECARAAGDAPLRSLEQANRTRFPFFSDVKGDHRLVLAAVETTVLVLIFAVSLLGNVC
ALVLVARRRRRGATACLVLNLFCADLLFISAIPLVLAVRWTEAWLLGPVACHLLFYVMTL
SGSVTILTLAAVSLERMVCIVHLQRGVRGPGRRARAVLLALIWGYSAVAALPLCVFFRVV
PQRLPGADQEISICTLIWPTIPGEISWDVSFVTLNFLVPGLVIVISYSKILQITKASRKR
LTVSLAYSESHQIRVSQQDFRLFRTLFLLMVSFFIMWSPIIITILLILIQNFKQDLVIWP
SLFFWVVAFTFANSALNPILYNMTLCRNEWKKIFCCFWFPEKGAILTDTSVKRNDLSIIS
G

Primary citation

Cryo-EM Structure of the apo FFAR4-Gq complex. Chen, G., Wu, Z.S., Qiu, C. To be published.

Other PDB entries of the same protein (UniProt P62873 (AlphaFold model), which also has an AlphaFold model), best resolution first:

8QEH 1.43 Å, Crystal structure of the G11 protein heterotrimer bound to FR900359 inhibitor
8QEG 1.7 Å, Crystal structure of the G11 protein heterotrimer bound to YM-254890 inhibitor
8F0K 1.9 Å, Human Amylin3 Receptor in complex with Gs and Pramlintide analogue peptide San385
9YDQ 1.94 Å, Human delta opioid receptor complex with mini-Gi and agonist DADLE and allosteric…
9YDP 1.95 Å, Human delta opioid receptor complex with mini-Gi and agonist DADLE
6CRK 2.0 Å, Heterotrimeric G-protein in complex with an antibody fragment
8F0J 2.0 Å, Calcitonin Receptor in complex with Gs and Pramlintide analogue peptide San45
8F2B 2.0 Å, Amylin 3 Receptor in complex with Gs and Pramlintide analogue peptide San45
9XXT 2.0 Å, Cryo-EM structure of lysophosphatidylserine (18:0)-bound GPR174-Gs complex
6X18 2.1 Å, GLP-1 peptide hormone bound to Glucagon-Like peptide-1 (GLP-1) Receptor
6X19 2.1 Å, Non peptide agonist CHU-128, bound to Glucagon-Like peptide-1 (GLP-1) Receptor
9NTU 2.1 Å, Cryo-EM structure of BETP-GLP-1(9-36)-GLP-1R-Gs complex

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