4DLX

H-Ras Set 1 CaCl2/DTE, ordered off


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.731 Å
  • R-Value Free: 0.198 
  • R-Value Work: 0.169 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Shift in the Equilibrium between On and Off States of the Allosteric Switch in Ras-GppNHp Affected by Small Molecules and Bulk Solvent Composition.

Holzapfel, G.Buhrman, G.Mattos, C.

(2012) Biochemistry 51: 6114-6126

  • DOI: 10.1021/bi300509j
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Ras GTPase cycles between its active GTP-bound form promoted by GEFs and its inactive GDP-bound form promoted by GAPs to affect the control of various cellular functions. It is becoming increasingly apparent that subtle regulation of the GTP-bound ac ...

    Ras GTPase cycles between its active GTP-bound form promoted by GEFs and its inactive GDP-bound form promoted by GAPs to affect the control of various cellular functions. It is becoming increasingly apparent that subtle regulation of the GTP-bound active state may occur through promotion of substates mediated by an allosteric switch mechanism that induces a disorder to order transition in switch II upon ligand binding at an allosteric site. We show with high-resolution structures that calcium acetate and either dithioerythritol (DTE) or dithiothreitol (DTT) soaked into H-Ras-GppNHp crystals in the presence of a moderate amount of poly(ethylene glycol) (PEG) can selectively shift the equilibrium to the "on" state, where the active site appears to be poised for catalysis (calcium acetate), or to what we call the "ordered off" state, which is associated with an anticatalytic conformation (DTE or DTT). We also show that the equilibrium is reversible in our crystals and dependent on the nature of the small molecule present. Calcium acetate binding in the allosteric site stabilizes the conformation observed in the H-Ras-GppNHp/NOR1A complex, and PEG, DTE, and DTT stabilize the anticatalytic conformation observed in the complex between the Ras homologue Ran and Importin-β. The small molecules are therefore selecting biologically relevant conformations in the crystal that are sampled by the disordered switch II in the uncomplexed GTP-bound form of H-Ras. In the presence of a large amount of PEG, the ordered off conformation predominates, whereas in solution, in the absence of PEG, switch regions appear to remain disordered in what we call the off state, unable to bind DTE.


    Organizational Affiliation

    Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 27695, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
GTPase HRas
A
166Homo sapiensMutation(s): 0 
Gene Names: HRAS (HRAS1)
Find proteins for P01112 (Homo sapiens)
Go to Gene View: HRAS
Go to UniProtKB:  P01112
Small Molecules
Ligands 4 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
DTU
Query on DTU

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Download CCD File 
A
(2R,3S)-1,4-DIMERCAPTOBUTANE-2,3-DIOL
C4 H10 O2 S2
VHJLVAABSRFDPM-ZXZARUISSA-N
 Ligand Interaction
CA
Query on CA

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Download CCD File 
A
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
MG
Query on MG

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Download CCD File 
A
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
GNP
Query on GNP

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Download CCD File 
A
PHOSPHOAMINOPHOSPHONIC ACID-GUANYLATE ESTER
C10 H17 N6 O13 P3
UQABYHGXWYXDTK-UUOKFMHZSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.731 Å
  • R-Value Free: 0.198 
  • R-Value Work: 0.169 
  • Space Group: H 3 2
Unit Cell:
Length (Å)Angle (°)
a = 88.085α = 90.00
b = 88.085β = 90.00
c = 133.900γ = 120.00
Software Package:
Software NamePurpose
HKL-2000data reduction
SCALEPACKdata scaling
HKL-2000data collection
DENZOdata reduction
PHENIXrefinement
PDB_EXTRACTdata extraction
PHENIXphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2012-08-08
    Type: Initial release
  • Version 1.1: 2012-08-15
    Type: Structure summary
  • Version 1.2: 2012-10-17
    Type: Database references
  • Version 1.3: 2017-11-15
    Type: Refinement description