1A0R

HETEROTRIMERIC COMPLEX OF PHOSDUCIN/TRANSDUCIN BETA-GAMMA


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.80 Å
  • R-Value Free: 0.264 
  • R-Value Work: 0.228 
  • R-Value Observed: 0.228 

Starting Model: experimental
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This is version 1.8 of the entry. See complete history


Literature

Phosducin induces a structural change in transducin beta gamma.

Loew, A.Ho, Y.K.Blundell, T.Bax, B.

(1998) Structure 6: 1007-1019

  • DOI: https://doi.org/10.1016/s0969-2126(98)00102-6
  • Primary Citation of Related Structures:  
    1A0R

  • PubMed Abstract: 

    Phosducin binds tightly to the beta gamma subunits (Gt beta gamma) of the heterotrimeric G protein transducin, preventing Gt beta gamma reassociation with Gt alpha-GDP and thereby inhibiting the G-protein cycle. Phosducin-like proteins appear to be widely distributed and may play important roles in regulating many heterotrimeric G-protein signaling pathways. The 2.8 A crystal structure of a complex of bovine retinal phosducin with Gt beta gamma shows how the two domains of phosducin cover one side and the top of the seven-bladed beta propeller of Gt beta gamma. The binding of phosducin induces a distinct structural change in the beta propeller of Gt beta gamma, such that a small cavity opens up between blades 6 and 7. Electron density in this cavity has been assigned to the farnesyl moiety of the gamma subunit. beta gamma subunits of heterotrimeric G proteins can exist in two distinct conformations. In the R (relaxed) state, corresponding to the structure of the free beta gamma or the structure of beta gamma in the alpha beta gamma heterotrimer, the hydrophobic farnesyl moiety of the gamma subunit is exposed, thereby mediating membrane association. In the T (tense) state, as observed in the phosducin-Gt beta gamma structure, the farnesyl moiety of the gamma subunit is effectively buried in the cavity formed between blades 6 and 7 of the beta subunit. Binding of phosducin to Gt beta gamma induces the formation of this cavity, resulting in a switch from the R to the T conformation. This sequesters beta gamma from the membrane to the cytosol and turns off the signal-transduction cascade. Regulation of this membrane association/dissociation switch of Gt beta gamma by phosducin may be a general mechanism for attenuation of G protein coupled signal transduction cascades.


  • Organizational Affiliation

    Department of Biochemistry and Molecular Biology, University of Illinois at Chicago, IL 60612-7334, USA.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
TRANSDUCIN (BETA SUBUNIT)A [auth B]340Bos taurusMutation(s): 0 
UniProt
Find proteins for P62871 (Bos taurus)
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Go to UniProtKB:  P62871
Entity Groups  
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UniProt GroupP62871
Sequence Annotations
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  • Reference Sequence
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Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
TRANSDUCIN (GAMMA SUBUNIT)B [auth G]65Bos taurusMutation(s): 0 
Membrane Entity: Yes 
UniProt
Find proteins for P02698 (Bos taurus)
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Go to UniProtKB:  P02698
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UniProt GroupP02698
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  • Reference Sequence
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Entity ID: 3
MoleculeChains Sequence LengthOrganismDetailsImage
PHOSDUCINC [auth P]245Bos taurusMutation(s): 0 
UniProt
Find proteins for P19632 (Bos taurus)
Explore P19632 
Go to UniProtKB:  P19632
Entity Groups  
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UniProt GroupP19632
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
FAR
Query on FAR

Download Ideal Coordinates CCD File 
D [auth G]FARNESYL
C15 H26
JXBSHSBNOVLGHF-BUJBXKITSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.80 Å
  • R-Value Free: 0.264 
  • R-Value Work: 0.228 
  • R-Value Observed: 0.228 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 76.09α = 90
b = 87.91β = 90
c = 98.74γ = 90
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORrefinement
XDSdata reduction
XSCALEdata scaling
X-PLORphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1998-12-30
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2018-04-04
    Changes: Advisory, Data collection, Other
  • Version 1.4: 2018-04-11
    Changes: Data collection
  • Version 1.5: 2020-06-24
    Changes: Advisory, Database references, Derived calculations
  • Version 1.6: 2023-08-02
    Changes: Database references, Derived calculations, Refinement description
  • Version 1.7: 2024-05-22
    Changes: Data collection
  • Version 1.8: 2024-10-16
    Changes: Structure summary