4DLU

H-Ras Set 1 Ca(OAc)2, on

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.60 Å
  • R-Value Free: 0.203 
  • R-Value Work: 0.182 
  • R-Value Observed: 0.183 

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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:  
    3V4F, 4DLR, 4DLS, 4DLT, 4DLU, 4DLV, 4DLW, 4DLX, 4DLY, 4DLZ

  • 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 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 ...

    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
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(by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
GTPase HRasA166Homo sapiensMutation(s): 0 
Gene Names: HRAS, HRAS1
EC: 3.6.5.2
UniProt & NIH Common Fund Data Resources
Find proteins for P01112 (Homo sapiens)
Explore P01112 
Go to UniProtKB:  P01112
PHAROS:  P01112
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP01112
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 4 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GNP
Query on GNP
Download Ideal Coordinates CCD File 
B [auth A]PHOSPHOAMINOPHOSPHONIC ACID-GUANYLATE ESTER
C10 H17 N6 O13 P3
UQABYHGXWYXDTK-UUOKFMHZSA-N		 Ligand Interaction
ACT
Query on ACT
Download Ideal Coordinates CCD File 
G [auth A]ACETATE ION
C2 H3 O2
QTBSBXVTEAMEQO-UHFFFAOYSA-M		 Ligand Interaction
CA
Query on CA
Download Ideal Coordinates CCD File 
C [auth A],
E [auth A]		CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N		 Ligand Interaction
MG
Query on MG
Download Ideal Coordinates CCD File 
D [auth A],
F [auth A]		MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N		 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.60 Å
  • R-Value Free: 0.203 
  • R-Value Work: 0.182 
  • R-Value Observed: 0.183 
  • Space Group: H 3 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 88.822α = 90
b = 88.822β = 90
c = 134.779γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PHENIXrefinement
PDB_EXTRACTdata extraction
HKL-2000data collection
HKL-2000data reduction
PHENIXphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

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