3RY9

Crystal Structure of the Resurrected Ancestral Glucocorticoid Receptor 1 in complex with DOC


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.95 Å
  • R-Value Free: 0.216 
  • R-Value Work: 0.181 

Starting Model: experimental
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This is version 1.2 of the entry. See complete history


Literature

Mechanisms for the evolution of a derived function in the ancestral glucocorticoid receptor.

Carroll, S.M.Ortlund, E.A.Thornton, J.W.

(2011) PLoS Genet 7: e1002117-e1002117

  • DOI: https://doi.org/10.1371/journal.pgen.1002117
  • Primary Citation of Related Structures:  
    3RY9

  • PubMed Abstract: 

    Understanding the genetic, structural, and biophysical mechanisms that caused protein functions to evolve is a central goal of molecular evolutionary studies. Ancestral sequence reconstruction (ASR) offers an experimental approach to these questions. Here we use ASR to shed light on the earliest functions and evolution of the glucocorticoid receptor (GR), a steroid-activated transcription factor that plays a key role in the regulation of vertebrate physiology. Prior work showed that GR and its paralog, the mineralocorticoid receptor (MR), duplicated from a common ancestor roughly 450 million years ago; the ancestral functions were largely conserved in the MR lineage, but the functions of GRs-reduced sensitivity to all hormones and increased selectivity for glucocorticoids-are derived. Although the mechanisms for the evolution of glucocorticoid specificity have been identified, how reduced sensitivity evolved has not yet been studied. Here we report on the reconstruction of the deepest ancestor in the GR lineage (AncGR1) and demonstrate that GR's reduced sensitivity evolved before the acquisition of restricted hormone specificity, shortly after the GR-MR split. Using site-directed mutagenesis, X-ray crystallography, and computational analyses of protein stability to recapitulate and determine the effects of historical mutations, we show that AncGR1's reduced ligand sensitivity evolved primarily due to three key substitutions. Two large-effect mutations weakened hydrogen bonds and van der Waals interactions within the ancestral protein, reducing its stability. The degenerative effect of these two mutations is extremely strong, but a third permissive substitution, which has no apparent effect on function in the ancestral background and is likely to have occurred first, buffered the effects of the destabilizing mutations. Taken together, our results highlight the potentially creative role of substitutions that partially degrade protein structure and function and reinforce the importance of permissive mutations in protein evolution.


  • Organizational Affiliation

    Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Ancestral Glucocorticoid Receptor 1
A, B
250synthetic constructMutation(s): 0 
Gene Names: resurrected gene
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.95 Å
  • R-Value Free: 0.216 
  • R-Value Work: 0.181 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 139.421α = 90
b = 49.144β = 105.82
c = 100.369γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
PDB_EXTRACTdata extraction
SERGUIdata collection
HKL-2000data reduction
HKL-2000data scaling
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-06-29
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2023-09-13
    Changes: Data collection, Database references, Derived calculations, Refinement description