Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 6-mer - A1B1C1D1E1F1 

Biological assembly 1 assigned by authors.

Biological Assembly Evidence: gel filtration

Macromolecule Content

• Total Structure Weight: 176.14 kDa 
• Atom Count: 8,660 
• Modelled Residue Count: 1,129 
• Deposited Residue Count: 1,581 
• Unique protein chains: 6

 7WJ5

Cryo-EM structure of human somatostatin receptor 2 complex with its agonist somatostatin delineates the ligand binding specificity

• PDB DOI:  https://doi.org/10.2210/pdb7WJ5/pdb
• EM Map EMD-32543: EMDB EMDataResource

• Classification: MEMBRANE PROTEIN/IMMUNE SYSTEM
• Organism(s): Homo sapiens, Escherichia coli
• Expression System: Spodoptera frugiperda
• Mutation(s): No 
• Membrane Protein: Yes  OPMPDBTM


• Deposited: 2022-01-05 Released: 2022-07-13 
• Deposition Author(s): Heo, Y.S., Yoon, E.J., Jeon, Y.E., Yun, J.-H., Ishimoto, N., Woo, H., Park, S.Y., Song, J., Lee, W.T.
• Funding Organization(s): National Research Foundation (NRF, Korea)

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Experimental Data Snapshot

• Method: ELECTRON MICROSCOPY
• Resolution: 3.72 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

Literature

Cryo-EM structure of the human somatostatin receptor 2 complex with its agonist somatostatin delineates the ligand-binding specificity.

Heo, Y., Yoon, E., Jeon, Y.E., Yun, J.H., Ishimoto, N., Woo, H., Park, S.Y., Song, J.J., Lee, W.

(2022) Elife 11

• PubMed: 35446253 
• DOI: https://doi.org/10.7554/eLife.76823
• Primary Citation of Related Structures:  
  7WJ5


• PubMed Abstract: 
  

Somatostatin is a peptide hormone that regulates endocrine systems by binding to G-protein-coupled somatostatin receptors. Somatostatin receptor 2 (SSTR2) is a human somatostatin receptor and is highly implicated in hormone disorders, cancers, and neurological diseases. Here, we report the high-resolution cryo-EM structure of full-length human SSTR2 bound to the agonist somatostatin (SST-14) in complex with inhibitory G (G _i ) proteins. Our structural and mutagenesis analyses show that seven transmembrane helices form a deep pocket for ligand binding and that SSTR2 recognizes the highly conserved Trp-Lys motif of SST-14 at the bottom of the pocket. Furthermore, our sequence analysis combined with AlphaFold modeled structures of other SSTR isoforms provide a structural basis for the mechanism by which SSTR family proteins specifically interact with their cognate ligands. This work provides the first glimpse into the molecular recognition mechanism of somatostatin receptors and a crucial resource to develop therapeutics targeting somatostatin receptors.

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Organizational Affiliation: 

PCG-Biotech, Ltd., 508 KBIZ DMC Tower, Sangam-Ro, Seoul, Republic of Korea.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Guanine nucleotide-binding protein G(i) subunit alpha-1	A	354	Homo sapiens	Mutation(s): 0  Gene Names: GNAI1 Membrane Entity: Yes
UniProt & NIH Common Fund Data Resources
Find proteins for P63096 (Homo sapiens) Explore P63096  Go to UniProtKB:  P63096
PHAROS:  P63096

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
Guanine nucleotide-binding protein G(I)/G(S)/G(T) subunit beta-1	B	358	Homo sapiens	Mutation(s): 0  Gene Names: GNB1
UniProt & NIH Common Fund Data Resources
Find proteins for P62873 (Homo sapiens) Explore P62873  Go to UniProtKB:  P62873
PHAROS:  P62873

Entity ID: 3
Molecule	Chains	Sequence Length	Organism	Details	Image
Guanine nucleotide-binding protein G(I)/G(S)/G(O) subunit gamma-2	C	71	Homo sapiens	Mutation(s): 0  Gene Names: GNG2 Membrane Entity: Yes
UniProt & NIH Common Fund Data Resources
Find proteins for P59768 (Homo sapiens) Explore P59768  Go to UniProtKB:  P59768
PHAROS:  P59768

Entity ID: 4
Molecule	Chains	Sequence Length	Organism	Details	Image
Gai1 antibody (scfv16)	D [auth E]	266	Homo sapiens	Mutation(s): 0

Entity ID: 5
Molecule	Chains	Sequence Length	Organism	Details	Image
Soluble cytochrome b562,Somatostatin receptor type 2	E [auth R]	518	Escherichia coli, Homo sapiens This entity is chimeric	Mutation(s): 0  Gene Names: cybC, SSTR2 Membrane Entity: Yes
UniProt & NIH Common Fund Data Resources
Find proteins for P30874 (Homo sapiens) Explore P30874  Go to UniProtKB:  P30874
PHAROS:  P30874
Find proteins for P0ABE7 (Escherichia coli) Explore P0ABE7  Go to UniProtKB:  P0ABE7
UniProt Groups	P0ABE7P30874

Entity ID: 6
Molecule	Chains	Sequence Length	Organism	Details	Image
Somatostatin-14 (SST-14)	F [auth S]	14	Homo sapiens	Mutation(s): 0  Gene Names: SST Membrane Entity: Yes
UniProt & NIH Common Fund Data Resources
Find proteins for P61278 (Homo sapiens) Explore P61278  Go to UniProtKB:  P61278
PHAROS:  P61278

Biologically Interesting Molecules (External Reference) 1 Unique

Entity ID: 6
ID	Chains	Name	Type/Class	2D Diagram	3D Interactions
PRD_001216	F [auth S]	Somatostatin-14	Cyclic peptide / Inhibitor		Ligand Interaction

Experimental Data & Validation

Experimental Data

• Method: ELECTRON MICROSCOPY
• Resolution: 3.72 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

EM Software:

Task	Software Package	Version
MODEL REFINEMENT	PHENIX	1.19.2-4158
RECONSTRUCTION	PHENIX	1.19.2-4158

Structure Validation

Entry History & Funding Information

Deposition Data

• Released Date: 2022-07-13 
Deposition Author(s): Heo, Y.S., Yoon, E.J., Jeon, Y.E., Yun, J.-H., Ishimoto, N., Woo, H., Park, S.Y., Song, J., Lee, W.T.

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Funding Organization	Location	Grant Number
National Research Foundation (NRF, Korea)	Korea, Republic Of	2020M3A9G7103934

Revision History  

• Version 1.0: 2022-07-13
  Type: Initial release