3LBH

Ras soaked in Calcium Acetate


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.85 Å
  • R-Value Free: 0.209 
  • R-Value Work: 0.174 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Allosteric modulation of Ras positions Q61 for a direct role in catalysis.

Buhrman, G.Holzapfel, G.Fetics, S.Mattos, C.

(2010) Proc.Natl.Acad.Sci.USA 107: 4931-4936

  • DOI: 10.1073/pnas.0912226107
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Ras and its effector Raf are key mediators of the Ras/Raf/MEK/ERK signal transduction pathway. Mutants of residue Q61 impair the GTPase activity of Ras and are found prominently in human cancers. Yet the mechanism through which Q61 contributes to cat ...

    Ras and its effector Raf are key mediators of the Ras/Raf/MEK/ERK signal transduction pathway. Mutants of residue Q61 impair the GTPase activity of Ras and are found prominently in human cancers. Yet the mechanism through which Q61 contributes to catalysis has been elusive. It is thought to position the catalytic water molecule for nucleophilic attack on the gamma-phosphate of GTP. However, we previously solved the structure of Ras from crystals with symmetry of the space group R32 in which switch II is disordered and found that the catalytic water molecule is present. Here we present a structure of wild-type Ras with calcium acetate from the crystallization mother liquor bound at a site remote from the active site and likely near the membrane. This results in a shift in helix 3/loop 7 and a network of H-bonding interactions that propagates across the molecule, culminating in the ordering of switch II and placement of Q61 in the active site in a previously unobserved conformation. This structure suggests a direct catalytic role for Q61 where it interacts with a water molecule that bridges one of the gamma-phosphate oxygen atoms to the hydroxyl group of Y32 to stabilize the transition state of the hydrolysis reaction. We propose that Raf together with the binding of Ca(2+) and a negatively charged group mimicked in our structure by the acetate molecule induces the ordering of switch I and switch II to complete the active site of Ras.


    Organizational Affiliation

    Department of Molecular and Structural Biochemistry, North Carolina State University, 128 Polk Hall-CB 7622, 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
ACT
Query on ACT

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A
ACETATE ION
C2 H3 O2
QTBSBXVTEAMEQO-UHFFFAOYSA-M
 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: 1.85 Å
  • R-Value Free: 0.209 
  • R-Value Work: 0.174 
  • Space Group: H 3 2
Unit Cell:
Length (Å)Angle (°)
a = 88.610α = 90.00
b = 88.610β = 90.00
c = 134.719γ = 120.00
Software Package:
Software NamePurpose
PHENIXphasing
SCALEPACKdata scaling
MAR345dtbdata collection
PHENIXrefinement
PHENIXmodel building
DENZOdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2010-03-02
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance