8ZBI: Somatostatin receptor 3 (SSTR3) with Gi1 complex

Cryo-EM structure of Somatostatin receptor 3 (SSTR3) with Gi1 complex. Determined by electron microscopy at 2.79 Å resolution. Released 30 Apr 2025.

Method: Electron microscopy
Resolution: 2.79 Å
Organism: Homo sapiens
Chains: 6
Atoms: 7,657
Mol. weight: 176.92 kDa
Released: 30 Apr 2025

Explore 8ZBI in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

8ZBI contains 22 α-helices and 71 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 B: 4 helices, 6 β-strands

Element	Residues	Length	Sheet
α-helix	7-29	23
α-helix	30-32	3
β-strand	33-38	6	1
β-strand	186-190	5	1
β-strand	195-200	6	1
α-helix	208-215	8
β-strand	221-223	3	1
β-strand	264-266	3	1
β-strand	319-321	3	1
α-helix	330-350	21

Chain C: 1 helix, 35 β-strands

Element	Residues	Length	Sheet
α-helix	30-34	5
β-strand	47-51	5	2
β-strand	58-63	6	3
β-strand	69-74	6	3
β-strand	78-83	6	3
β-strand	88-94	7	3
β-strand	100-105	6	4
β-strand	111-116	6	4
β-strand	121-125	5	4
β-strand	134-139	6	4
β-strand	146-151	6	5
β-strand	157-161	5	5
β-strand	166-170	5	5
β-strand	175-179	5	5
β-strand	187	1	6
β-strand	191-192	2	7
β-strand	198-202	5	7
β-strand	203	1	6
β-strand	207-212	6	7
β-strand	218-223	6	7
β-strand	229-234	6	8
β-strand	240-245	6	8
β-strand	250-254	5	8
β-strand	263	1	8
β-strand	266	1	9
β-strand	269	1	9
β-strand	273-278	6	10
β-strand	284-289	6	10
β-strand	294-295	2	11
β-strand	297-298	2	10
β-strand	307-308	2	11
β-strand	315	1	12
β-strand	319-320	2	2
β-strand	327-330	4	2
β-strand	331	1	12
β-strand	336-339	4	2

Chain D: 13 helices, 2 β-strands

Element	Residues	Length	Sheet
α-helix	43-71	29
α-helix	79-106	28
α-helix	114-146	33
α-helix	157-174	18
α-helix	176-181	6
β-strand	182-183	2	21
β-strand	192-193	2	21
α-helix	199-211	13
α-helix	212-216	5
α-helix	218-238	21
α-helix	248-253	6
α-helix	257-282	26
α-helix	289-291	3
α-helix	292-313	22
α-helix	318-324	7

Chain E: 1 helix, 0 β-strands

Element	Residues	Length	Sheet
α-helix	30-43	14

Chain F: 3 helices, 28 β-strands

Element	Residues	Length	Sheet
β-strand	41-45	5	13
β-strand	48-50	3	14
β-strand	56-63	8	13
α-helix	67-69	3
β-strand	71-77	7	14
β-strand	83-89	7	14
β-strand	96-98	3	14
β-strand	106-111	6	13
β-strand	116-121	6	13
α-helix	126-128	3
β-strand	130-137	8	14
β-strand	149	1	14
β-strand	151	1	13
β-strand	153-157	5	14
β-strand	178-179	2	15
β-strand	185-186	2	16
β-strand	193-197	5	17
β-strand	198-199	2	15
β-strand	204	1	18
β-strand	210	1	18
β-strand	212-217	6	19
β-strand	224-225	2	19
β-strand	227-228	2	20
β-strand	232-233	2	20
α-helix	234	1
β-strand	241-244	4	17
β-strand	250-254	5	17
β-strand	264-269	6	19
β-strand	277	1	19
β-strand	281-282	2	19
β-strand	283-284	2	16

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Guanine nucleotide-binding protein G(i) subunit alpha-1	B	protein	354	Homo sapiens	P63096 (AlphaFold model)
Guanine nucleotide-binding protein G(I)/G(S)/G(T) subunit beta-1	C	protein	345	Homo sapiens	P62873 (AlphaFold model)
Guanine nucleotide-binding protein G(I)/G(S)/G(O) subunit gamma-2	E	protein	71	Homo sapiens	P59768 (AlphaFold model)
scFv16	F	protein	296	Homo sapiens
Soluble cytochrome b562,Somatostatin receptor type 3	D	protein	524	Homo sapiens	P32745 (AlphaFold model)
Somatostatin-14	S	protein	14	Homo sapiens	P61278

Sequence of entity 1 (B), FASTA

>8ZBI_1 Guanine nucleotide-binding protein G(i) subunit alpha-1 (chains B)
MGCTLSAEDKAAVERSKMIDRNLREDGEKAAREVKLLLLGAGESGKSTIVKQMKIIHEAG
YSEEECKQYKAVVYSNTIQSIIAIIRAMGRLKIDFGDSARADDARQLFVLAGAAEEGFMT
AELAGVIKRLWKDSGVQACFNRSREYQLNDSAAYYLNDLDRIAQPNYIPTQQDVLRTRVK
TTGIVETHFTFKDLHFKMFDVGGQRSERKKWIHCFEGVTAIIFCVALSDYDLVLAEDEEM
NRMHESMKLFDSICNNKWFTDTSIILFLNKKDLFEEKIKKSPLTICYPEYAGSNTYEEAA
AYIQCQFEDLNKRKDTKEIYTHFTCATDTKNVQFVFDAVTDVIIKNNLKDCGLF

Sequence of entity 2 (C), FASTA

>8ZBI_2 Guanine nucleotide-binding protein G(I)/G(S)/G(T) subunit beta-1 (chains C)
GPGSSGSELDQLRQEAEQLKNQIRDARKACADATLSQITNNIDPVGRIQMRTRRTLRGHL
AKIYAMHWGTDSRLLVSASQDGKLIIWDSYTTNKVHAIPLRSSWVMTCAYAPSGNYVACG
GLDNICSIYNLKTREGNVRVSRELAGHTGYLSCCRFLDDNQIVTSSGDTTCALWDIETGQ
QTTTFTGHTGDVMSLSLAPDTRLFVSGACDASAKLWDVREGMCRQTFTGHESDINAICFF
PNGNAFATGSDDATCRLFDLRADQELMTYSHDNIICGITSVSFSKSGRLLLAGYDDFNCN
VWDALKADRAGVLAGHDNRVSCLGVTDDGMAVATGSWDSFLKIWN

Sequence of entity 3 (E), FASTA

>8ZBI_3 Guanine nucleotide-binding protein G(I)/G(S)/G(O) subunit gamma-2 (chains E)
MASNNTASIAQARKLVEQLKMEANIDRIKVSKAAADLMAYCEAHAKEDPLLTPVPASENP
FREKKFFCAIL

Sequence of entity 4 (F), FASTA

>8ZBI_4 scFv16 (chains F)
MLLVNQSHQGFNKEHTSKMVSAIVLYVLLAAAAHSAFADVQLVESGGGLVQPGGSRKLSC
SASGFAFSSFGMHWVRQAPEKGLEWVAYISSGSGTIYYADTVKGRFTISRDDPKNTLFLQ
MTSLRSEDTAMYYCVRSIYYYGSSPFDFWGQGTTLTVSSGGGGSGGGGSGGGGSDIVMTQ
ATSSVPVTPGESVSISCRSSKSLLHSNGNTYLYWFLQRPGQSPQLLIYRMSNLASGVPDR
FSGSGSGTAFTLTISRLEAEDVGVYYCMQHLEYPLTFGAGTKLELKAAAENLYFQG

Sequence of entity 5 (D), FASTA

>8ZBI_5 Soluble cytochrome b562,Somatostatin receptor type 3 (chains D)
ADLEDNWETLNDNLKVIEKADNAAQVKDALTKMRAAALDAQKATPPKLEDKSPDSPEMKD
FRHGFDILVGQIDDALKLANEGKVKEAQAAAEQLKTTRNAYIQKYLMDMLHPSSVSTTSE
PENASSAWPPDATLGNVSAGPSPAGLAVSGVLIPLVYLVVCVVGLLGNSLVIYVVLRHTA
SPSVTNVYILNLALADELFMLGLPFLAAQNALSYWPFGSLMCRLVMAVDGINQFTSIFCL
TVMSVDRYLAVVHPTRSARWRTAPVARTVSAAVWVASAVVVLPVVVFSGVPRGMSTCHMQ
WPEPAAAWRAGFIIYTAALGFFGPLLVICLCYLLIVVKVRSAGRRVWAPSCQRRRRSERR
VTRMVVAVVALFVLCWMPFYVLNIVNVVCPLPEEPAFFGLYFLVVALPYANSCANPILYG
FLSYRFKQGFRRVLLRPSRRVRSQEPTVGPPEKTEEEDEEEEDGEESREGGKGKEMNGRV
SQITQPGTSGQERPPSRVASKEQQLLPQEASTGEKSSTMRISYL

Sequence of entity 6 (S), FASTA

>8ZBI_6 Somatostatin-14 (chains S)
AGCKNFFWKTFTSC

Primary citation

The structures of SSTR3 and SSTR5 provide insights into the specificity among somatostatin receptors. Heo, Y., Kim, Y., Cho, M. et al. To be published.

Other PDB entries of the same protein (UniProt P63096 (AlphaFold model), which also has an AlphaFold model), best resolution first:

6CRK 2.0 Å, Heterotrimeric G-protein in complex with an antibody fragment
3UMR 2.04 Å, Crystal structure of the G202D mutant of human G-alpha-i1
9P7Z 2.1 Å, NTSR1-Gi-NTS(8-13) Complex in the Canonical, AHD Open State (C-Open-Apo)
2OM2 2.2 Å, Crystal Structure Of Human G[alpha]i1 Bound To The Goloco Motif Of Rgs14
8YN9 2.3 Å, Cryo-EM structure of histamine H4 receptor in complex with histamine and Gi
9HYI 2.3 Å, DP81-bound serotonin 5-HT1A receptor - Gi Protein Complex
9O36 2.3 Å, CryoEM structure of mu-opioid receptor - Gi protein complex bound to fluornitrazene (FNZ)
9P80 2.3 Å, NTSR1-Gi-NTS(8-13) Complex in the Non-Canonical, AHD Open State (NC-Open-Apo)
8XXV 2.33 Å, Cryo-EM Structure of the Prostaglandin D2 Receptor 2-indomethacin Coupled to G Protein
3UMS 2.34 Å, Crystal structure of the G202A mutant of human G-alpha-i1
3ONW 2.38 Å, Structure of a G-alpha-i1 mutant with enhanced affinity for the RGS14 GoLoco motif.
20ZG 2.4 Å, Cryo-EM structure of the human neurotensin receptor 1 (hNTSR1)-Gi1 complex in the…

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