Crystal structure of GDP-bound T50I mutant of human KRAS4B

Experimental Data Snapshot

  • Resolution: 2.20 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.211 
  • R-Value Observed: 0.213 

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Structural and functional analyses of a germline KRAS T50I mutation provide insights into Raf activation.

Chen, P.Y.Huang, B.J.Harris, M.Boone, C.Wang, W.Carias, H.Mesiona, B.Mavrici, D.Kohler, A.C.Bollag, G.Zhang, C.Zhang, Y.Shannon, K.

(2023) JCI Insight 8

  • DOI: https://doi.org/10.1172/jci.insight.168445
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    A T50I substitution in the K-Ras interswitch domain causes Noonan syndrome and emerged as a third-site mutation that restored the in vivo transforming activity and constitutive MAPK pathway activation by an attenuated KrasG12D,E37G oncogene in a mouse leukemia model. Biochemical and crystallographic data suggested that K-RasT50I increases MAPK signal output through a non-GTPase mechanism, potentially by promoting asymmetric Ras:Ras interactions between T50 and E162. We generated a "switchable" system in which K-Ras mutant proteins expressed at physiologic levels supplant the fms like tyrosine kinase 3 (FLT3) dependency of MOLM-13 leukemia cells lacking endogenous KRAS and used this system to interrogate single or compound G12D, T50I, D154Q, and E162L mutations. These studies support a key role for the asymmetric lateral assembly of K-Ras in a plasma membrane-distal orientation that promotes the formation of active Ras:Raf complexes in a membrane-proximal conformation. Disease-causing mutations such as T50I are a valuable starting point for illuminating normal Ras function, elucidating mechanisms of disease, and identifying potential therapeutic opportunities for Rasopathy disorders and cancer.

  • Organizational Affiliation

    Department of Pediatrics, UCSF, San Francisco, California, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Isoform 2B of GTPase KRas
A, B, C
170Homo sapiensMutation(s): 1 
UniProt & NIH Common Fund Data Resources
Find proteins for P01116 (Homo sapiens)
Explore P01116 
Go to UniProtKB:  P01116
PHAROS:  P01116
GTEx:  ENSG00000133703 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP01116
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.20 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.211 
  • R-Value Observed: 0.213 
  • Space Group: P 61 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 70.11α = 90
b = 70.11β = 90
c = 337.61γ = 120
Software Package:
Software NamePurpose
SCALAdata scaling
PDB_EXTRACTdata extraction
XDSdata reduction

Structure Validation

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Ligand Structure Quality Assessment 

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
Not funded--

Revision History  (Full details and data files)

  • Version 1.0: 2022-12-14
    Type: Initial release
  • Version 1.1: 2023-10-25
    Changes: Data collection, Refinement description
  • Version 1.2: 2023-12-27
    Changes: Database references