4PAS | pdb_00004pas

Heterodimeric coiled-coil structure of human GABA(B) receptor

• PDB DOI: https://doi.org/10.2210/pdb4PAS/pdb

• Classification: SIGNALING PROTEIN
• Organism(s): Homo sapiens
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2014-04-10 Released: 2014-05-07 
• Deposition Author(s): Burmakina, S., Geng, Y., Chen, Y., Fan, Q.R.
• Funding Organization(s): National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.62 Å
• R-Value Free: 
  0.217 (Depositor), 0.217 (DCC) 
• R-Value Work: 
  0.193 (Depositor), 0.190 (DCC) 
• R-Value Observed: 
  0.194 (Depositor) 

Literature

Heterodimeric coiled-coil interactions of human GABAB receptor.

Burmakina, S., Geng, Y., Chen, Y., Fan, Q.R.

(2014) Proc Natl Acad Sci U S A 111: 6958-6963

• PubMed: 24778228 
• DOI: https://doi.org/10.1073/pnas.1400081111
• Primary Citation Related Structures: 
  4PAS


• PubMed Abstract: 
  

  Metabotropic GABAB receptor is a G protein-coupled receptor that mediates inhibitory neurotransmission in the CNS. It functions as an obligatory heterodimer of GABAB receptor 1 (GBR1) and GABAB receptor 2 (GBR2) subunits. The association between GBR1 and GBR2 masks an endoplasmic reticulum (ER) retention signal in the cytoplasmic region of GBR1 and facilitates cell surface expression of both subunits. Here, we present, to our knowledge, the first crystal structure of an intracellular coiled-coil heterodimer of human GABAB receptor. We found that polar interactions buried within the hydrophobic core determine the specificity of heterodimer pairing. Disruption of the hydrophobic coiled-coil interface with single mutations in either subunit impairs surface expression of GBR1, confirming that the coiled-coil interaction is required to inactivate the adjacent ER retention signal of GBR1. The coiled-coil assembly buries an internalization motif of GBR1 at the heterodimer interface. The ER retention signal of GBR1 is not part of the core coiled-coil structure, suggesting that it is sterically shielded by GBR2 upon heterodimer formation.

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Organizational Affiliation: 
• Departments of Pharmacology and.
Departments of Pharmacology andPathology and Cell Biology, Columbia University, New York, NY 10032 [e-mail].

Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 2-mer - A1B1 Pseudo Symmetry: Cyclic - C2  (Explore in 3D)
Pseudo Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content 

• Total Structure Weight: 9.74 kDa 
• Atom Count: 689 
• Modeled Residue Count: 74 
• Deposited Residue Count: 82 
• Unique protein chains: 2

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Gamma-aminobutyric acid type B receptor subunit 1	A	41	Homo sapiens	Mutation(s): 0  Gene Names: GABBR1, GPRC3A
UniProt & NIH Common Fund Data Resources
Find proteins for Q9UBS5 (Homo sapiens) Explore Q9UBS5  Go to UniProtKB:  Q9UBS5
PHAROS:  Q9UBS5 GTEx:  ENSG00000204681

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
Gamma-aminobutyric acid type B receptor subunit 2	B	41	Homo sapiens	Mutation(s): 0  Gene Names: GABBR2, GPR51, GPRC3B
UniProt & NIH Common Fund Data Resources
Find proteins for O75899 (Homo sapiens) Explore O75899  Go to UniProtKB:  O75899
PHAROS:  O75899 GTEx:  ENSG00000136928

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.62 Å
• R-Value Free:  0.217 (Depositor), 0.217 (DCC) 
• R-Value Work:  0.193 (Depositor), 0.190 (DCC) 
• R-Value Observed: 0.194 (Depositor) 

Space Group: C 2 2 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 46.721	α = 90
b = 54.654	β = 90
c = 55.347	γ = 90

Software Package:

Software Name	Purpose
HKL-2000	data reduction
REFMAC	refinement
PDB_EXTRACT	data extraction

Structure Validation

Entry History 

& Funding Information

Deposition Data

• Released Date: 2014-05-07 
Deposition Author(s): Burmakina, S., Geng, Y., Chen, Y., Fan, Q.R.

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Funding Organization	Location	Grant Number
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)	United States	5R01GM088454-05

Revision History  

• Version 1.0: 2014-05-07
  Type: Initial release
  
• Version 1.1: 2014-05-14
  Changes: Database references
• Version 1.2: 2014-07-16
  Changes: Database references
• Version 1.3: 2017-09-27
  Changes: Author supporting evidence, Database references, Derived calculations, Other, Source and taxonomy
• Version 1.4: 2019-12-25
  Changes: Author supporting evidence
• Version 1.5: 2023-12-27
  Changes: Data collection, Database references, Refinement description