2VDX

Crystal Structure of the reactive loop Cleaved Corticosteroid Binding Globulin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.84 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.192 
  • R-Value Observed: 0.194 

Starting Model: experimental
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This is version 1.3 of the entry. See complete history


Literature

The S-to-R Transition of Corticosteroid-Binding Globulin and the Mechanism of Hormone Release.

Zhou, A.Wei, Z.Stanley, P.L.Read, R.J.Stein, P.E.Carrell, R.W.

(2008) J Mol Biol 380: 244

  • DOI: https://doi.org/10.1016/j.jmb.2008.05.012
  • Primary Citation of Related Structures:  
    2VDX, 2VDY

  • PubMed Abstract: 

    Corticosteroids are transported in the blood by a serpin, corticosteroid-binding globulin (CBG), and their normally equilibrated release can be further triggered by the cleavage of the reactive loop of CBG. We report here the crystal structures of cleaved human CBG (cCBG) at 1.8-A resolution and its complex with cortisol at 2.3-A resolution. As expected, on cleavage, CBG undergoes the irreversible S-to-R serpin transition, with the cleaved reactive loops being fully incorporated into the central beta-sheet. A connecting loop of helix D, which is in a helix-like conformation in native CBG, unwinds and grossly perturbs the hormone binding site following beta-sheet expansion in the cCBG structure but shifts away from the binding site by more than 8 A following the binding of cortisol. Unexpectedly, on cortisol binding, the hormone binding site of cCBG adopts a configuration almost identical with that of the native conformer. We conclude that CBG has adapted an allosteric mechanism of the serpins to allow equilibrated release of the hormones by a flip-flop movement of the intact reactive loop into and out of the beta-sheet. The change in the hormone binding affinity results from a change in the flexibility or plasticity of the connecting loop, which modulates the configuration of the binding site.


  • Organizational Affiliation

    Department of Haematology and Medicine, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK. awz20@cam.ac.uk


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
CORTICOSTEROID-BINDING GLOBULIN
A, B
373Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for P08185 (Homo sapiens)
Explore P08185 
Go to UniProtKB:  P08185
PHAROS:  P08185
GTEx:  ENSG00000170099 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP08185
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.84 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.192 
  • R-Value Observed: 0.194 
  • Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 39.941α = 81.94
b = 39.74β = 84.06
c = 112.113γ = 65.39
Software Package:
Software NamePurpose
REFMACrefinement
MOSFLMdata reduction
SCALAdata scaling
PHASERphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2008-05-06
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Advisory, Refinement description, Version format compliance
  • Version 1.2: 2017-11-08
    Changes: Advisory, Source and taxonomy
  • Version 1.3: 2023-12-13
    Changes: Advisory, Data collection, Database references, Derived calculations, Other, Refinement description