4LRW

Crystal Structure of K-Ras G12C (cysteine-light), GDP-bound

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.15 Å
  • R-Value Free: 0.204 
  • R-Value Work: 0.180 
  • R-Value Observed: 0.183 

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This is version 1.2 of the entry. See complete history. 


Literature

K-Ras(G12C) inhibitors allosterically control GTP affinity and effector interactions.

Ostrem, J.M., Peters, U., Sos, M.L., Wells, J.A., Shokat, K.M.

(2013) Nature 503: 548-551

  • DOI: 10.1038/nature12796
  • Primary Citation of Related Structures:  
    4L8G, 4L9S, 4L9W, 4LPK, 4LRW, 4LUC, 4LV6, 4LYF, 4LYH, 4LYJ, 4M1O, 4M1S, 4M1T, 4M1W, 4M1Y, 4M21, 4M22

  • PubMed Abstract: 

    • Somatic mutations in the small GTPase K-Ras are the most common activating lesions found in human cancer, and are generally associated with poor response to standard therapies. Efforts to target this oncogene directly have faced difficulties owing to its picomolar affinity for GTP/GDP and the absence of known allosteric regulatory sites ...

    Somatic mutations in the small GTPase K-Ras are the most common activating lesions found in human cancer, and are generally associated with poor response to standard therapies. Efforts to target this oncogene directly have faced difficulties owing to its picomolar affinity for GTP/GDP and the absence of known allosteric regulatory sites. Oncogenic mutations result in functional activation of Ras family proteins by impairing GTP hydrolysis. With diminished regulation by GTPase activity, the nucleotide state of Ras becomes more dependent on relative nucleotide affinity and concentration. This gives GTP an advantage over GDP and increases the proportion of active GTP-bound Ras. Here we report the development of small molecules that irreversibly bind to a common oncogenic mutant, K-Ras(G12C). These compounds rely on the mutant cysteine for binding and therefore do not affect the wild-type protein. Crystallographic studies reveal the formation of a new pocket that is not apparent in previous structures of Ras, beneath the effector binding switch-II region. Binding of these inhibitors to K-Ras(G12C) disrupts both switch-I and switch-II, subverting the native nucleotide preference to favour GDP over GTP and impairing binding to Raf. Our data provide structure-based validation of a new allosteric regulatory site on Ras that is targetable in a mutant-specific manner.

    Organizational Affiliation: 

    1] Department of Cellular and Molecular Pharmacology, Howard Hughes Medical Institute, University of California, San Francisco, California 94158, USA [2].



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
GTPase KRasA, B170Homo sapiensMutation(s): 4 
Gene Names: KRAS, KRAS isoform 2B, KRAS2, RASK2
EC: 3.6.5.2
UniProt & NIH Common Fund Data Resources
Find proteins for P01116 (Homo sapiens)
Explore P01116 
Go to UniProtKB:  P01116
PHAROS:  P01116
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP01116
Protein Feature View
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  • Reference Sequence
Small Molecules
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.15 Å
  • R-Value Free: 0.204 
  • R-Value Work: 0.180 
  • R-Value Observed: 0.183 
  • Space Group: P 3
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 82.862α = 90
b = 82.862β = 90
c = 38.397γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PHASERphasing
PHENIXrefinement
PDB_EXTRACTdata extraction
BOSdata collection
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Ligand Structure Quality Assessment 


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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-11-27
    Type: Initial release
  • Version 1.1: 2013-12-18
    Changes: Database references
  • Version 1.2: 2017-11-15
    Changes: Refinement description