3KSY

Crystal structure of the Histone domain, DH-PH unit, and catalytic unit of the Ras activator Son of Sevenless (SOS)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.178 Å
  • R-Value Free: 0.312 
  • R-Value Work: 0.259 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Role of the histone domain in the autoinhibition and activation of the Ras activator Son of Sevenless.

Gureasko, J.Kuchment, O.Makino, D.L.Sondermann, H.Bar-Sagi, D.Kuriyan, J.

(2010) Proc.Natl.Acad.Sci.USA 107: 3430-3435

  • DOI: 10.1073/pnas.0913915107

  • PubMed Abstract: 
  • Membrane-bound Ras is activated by translocation of the Son of Sevenless (SOS) protein to the plasma membrane. SOS is inactive unless Ras is bound to an allosteric site on SOS, and the Dbl homology (DH) and Pleckstrin homology (PH) domains of SOS (th ...

    Membrane-bound Ras is activated by translocation of the Son of Sevenless (SOS) protein to the plasma membrane. SOS is inactive unless Ras is bound to an allosteric site on SOS, and the Dbl homology (DH) and Pleckstrin homology (PH) domains of SOS (the DH-PH unit) block allosteric Ras binding. We showed previously that the activity of SOS at the membrane increases with the density of PIP(2) and the local concentration of Ras-GTP, which synergize to release the DH-PH unit. Here we present a new crystal structure of SOS that contains the N-terminal histone domain in addition to the DH-PH unit and the catalytic unit (SOS(HDFC), residues 1-1049). The structure reveals that the histone domain plays a dual role in occluding the allosteric site and in stabilizing the autoinhibitory conformation of the DH-PH unit. Additional insight is provided by kinetic analysis of the activation of membrane-bound Ras by mutant forms of SOS that contain mutations in the histone and the PH domains (E108K, C441Y, and E433K) that are associated with Noonan syndrome, a disease caused by hyperactive Ras signaling. Our results indicate that the histone domain and the DH-PH unit are conformationally coupled, and that the simultaneous engagement of the membrane by a PH domain PIP(2)-binding interaction and electrostatic interactions between a conserved positively charged patch on the histone domain and the negatively charged membrane coincides with a productive reorientation of SOS at the membrane and increased accessibility of both Ras binding sites on SOS.


    Organizational Affiliation

    Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Son of sevenless homolog 1
A
1049Homo sapiensMutation(s): 0 
Gene Names: SOS1
Find proteins for Q07889 (Homo sapiens)
Go to Gene View: SOS1
Go to UniProtKB:  Q07889
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.178 Å
  • R-Value Free: 0.312 
  • R-Value Work: 0.259 
  • Space Group: C 2 2 21
Unit Cell:
Length (Å)Angle (°)
a = 150.961α = 90.00
b = 160.918β = 90.00
c = 118.868γ = 90.00
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
SCALEPACKdata scaling
PHENIXrefinement
DENZOdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2010-02-16
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance
  • Version 1.2: 2017-11-01
    Type: Advisory, Refinement description