2II0

Crystal Structure of catalytic domain of Son of sevenless (Rem-Cdc25) in the absence of Ras


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.02 Å
  • R-Value Free: 0.248 
  • R-Value Work: 0.218 
  • R-Value Observed: 0.218 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

A Ras-induced conformational switch in the Ras activator Son of sevenless.

Freedman, T.S.Sondermann, H.Friedland, G.D.Kortemme, T.Bar-Sagi, D.Marqusee, S.Kuriyan, J.

(2006) Proc Natl Acad Sci U S A 103: 16692-16697

  • DOI: 10.1073/pnas.0608127103
  • Primary Citation of Related Structures:  
    2II0, 2IJE

  • PubMed Abstract: 
  • The Ras-specific guanine nucleotide-exchange factors Son of sevenless (Sos) and Ras guanine nucleotide-releasing factor 1 (RasGRF1) transduce extracellular stimuli into Ras activation by catalyzing the exchange of Ras-bound GDP for GTP. A truncated form of RasGRF1 containing only the core catalytic Cdc25 domain is sufficient for stimulating Ras nucleotide exchange, whereas the isolated Cdc25 domain of Sos is inactive ...

    The Ras-specific guanine nucleotide-exchange factors Son of sevenless (Sos) and Ras guanine nucleotide-releasing factor 1 (RasGRF1) transduce extracellular stimuli into Ras activation by catalyzing the exchange of Ras-bound GDP for GTP. A truncated form of RasGRF1 containing only the core catalytic Cdc25 domain is sufficient for stimulating Ras nucleotide exchange, whereas the isolated Cdc25 domain of Sos is inactive. At a site distal to the catalytic site, nucleotide-bound Ras binds to Sos, making contacts with the Cdc25 domain and with a Ras exchanger motif (Rem) domain. This allosteric Ras binding stimulates nucleotide exchange by Sos, but the mechanism by which this stimulation occurs has not been defined. We present a crystal structure of the Rem and Cdc25 domains of Sos determined at 2.0-A resolution in the absence of Ras. Differences between this structure and that of Sos bound to two Ras molecules show that allosteric activation of Sos by Ras occurs through a rotation of the Rem domain that is coupled to a rotation of a helical hairpin at the Sos catalytic site. This motion relieves steric occlusion of the catalytic site, allowing substrate Ras binding and nucleotide exchange. A structure of the isolated RasGRF1 Cdc25 domain determined at 2.2-A resolution, combined with computational analyses, suggests that the Cdc25 domain of RasGRF1 is able to maintain an active conformation in isolation because the helical hairpin has strengthened interactions with the Cdc25 domain core. These results indicate that RasGRF1 lacks the allosteric activation switch that is crucial for Sos activity.


    Organizational Affiliation

    Department of Molecular and Cell Biology, California Institute for Quantitative Biomedical Research, University of California, Berkeley, CA 94720, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Son of sevenless homolog 1A490Homo sapiensMutation(s): 0 
Gene Names: SOS1
Find proteins for Q07889 (Homo sapiens)
Explore Q07889 
Go to UniProtKB:  Q07889
NIH Common Fund Data Resources
PHAROS:  Q07889
Protein Feature View
Expand
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.02 Å
  • R-Value Free: 0.248 
  • R-Value Work: 0.218 
  • R-Value Observed: 0.218 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 82.771α = 90
b = 66.799β = 108.91
c = 119.653γ = 90
Software Package:
Software NamePurpose
CNSrefinement
ADSCdata collection
HKL-2000data reduction
HKL-2000data scaling
MOLREPphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2006-10-31
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance