2VDY

Crystal structure of the reactive loop cleaved Corticosteroid Binding Globulin complexed with Cortisol


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.271 
  • R-Value Work: 0.210 

wwPDB Validation 3D Report Full Report


This is version 1.2 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: 10.1016/j.jmb.2008.05.012
  • Primary Citation of Related Structures:  

  • 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 cl ...

    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: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
CORTICOSTEROID-BINDING GLOBULIN
A, B
373Homo sapiensMutation(s): 0 
Gene Names: SERPINA6 (CBG)
Find proteins for P08185 (Homo sapiens)
Go to Gene View: SERPINA6
Go to UniProtKB:  P08185
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
HCY
Query on HCY

Download SDF File 
Download CCD File 
A, B
(11alpha,14beta)-11,17,21-trihydroxypregn-4-ene-3,20-dione
CORTISOL
C21 H30 O5
JYGXADMDTFJGBT-VWUMJDOOSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.271 
  • R-Value Work: 0.210 
  • Space Group: P 1
Unit Cell:
Length (Å)Angle (°)
a = 38.673α = 83.09
b = 39.757β = 85.70
c = 111.586γ = 69.42
Software Package:
Software NamePurpose
MOSFLMdata reduction
REFMACrefinement
SCALAdata scaling
PHASERphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2008-05-13
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Advisory, Refinement description, Version format compliance
  • Version 1.2: 2017-11-08
    Type: Source and taxonomy