Structural basis of impaired hydrolysis in KRAS Q61H mutant

Experimental Data Snapshot

  • Resolution: 2.20 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.204 
  • R-Value Observed: 0.207 

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This is version 1.4 of the entry. See complete history


KRASQ61HPreferentially Signals through MAPK in a RAF Dimer-Dependent Manner in Non-Small Cell Lung Cancer.

Zhou, Z.W.Ambrogio, C.Bera, A.K.Li, Q.Li, X.X.Li, L.Son, J.Gondi, S.Li, J.Campbell, E.Jin, H.Okoro, J.J.Xu, C.X.Janne, P.A.Westover, K.D.

(2020) Cancer Res 80: 3719-3731

  • DOI: https://doi.org/10.1158/0008-5472.CAN-20-0448
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Assembly of RAS molecules into complexes at the cell membrane is critical for RAS signaling. We previously showed that oncogenic KRAS codon 61 mutations increase its affinity for RAF, raising the possibility that KRAS Q61H , the most common KRAS mutation at codon 61, upregulates RAS signaling through mechanisms at the level of RAS assemblies. We show here that KRAS Q61H exhibits preferential binding to RAF relative to PI3K in cells, leading to enhanced MAPK signaling in in vitro models and human NSCLC tumors. X-ray crystallography of KRAS Q61H :GTP revealed that a hyperdynamic switch 2 allows for a more stable interaction with switch 1, suggesting that enhanced RAF activity arises from a combination of absent intrinsic GTP hydrolysis activity and increased affinity for RAF. Disruption of KRAS Q61H assemblies by the RAS oligomer-disrupting D154Q mutation impaired RAF dimerization and altered MAPK signaling but had little effect on PI3K signaling. However, KRAS Q61H oligomers but not KRAS G12D oligomers were disrupted by RAF mutations that disrupt RAF-RAF interactions. KRAS Q61H cells show enhanced sensitivity to RAF and MEK inhibitors individually, whereas combined treatment elicited synergistic growth inhibition. Furthermore, KRAS Q61H tumors in mice exhibited high vulnerability to MEK inhibitor, consistent with cooperativity between KRAS Q61H and RAF oligomerization and dependence on MAPK signaling. These findings support the notion that KRAS Q61H and functionally similar mutations may serve as predictive biomarkers for targeted therapies against the MAPK pathway. SIGNIFICANCE: These findings show that oncogenic KRAS Q61H forms a cooperative RAS-RAF ternary complex, which renders RAS-driven tumors vulnerable to MEKi and RAFi, thus establishing a framework for evaluating RAS biomarker-driven targeted therapies.

  • Organizational Affiliation

    Departments of Biochemistry and Radiation Oncology, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
GTPase KRas
A, B, C, D, E
A, B, C, D, E, F
169Homo 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
Small Molecules
Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on GTP

Download Ideal Coordinates CCD File 
G [auth A]
I [auth B]
K [auth C]
M [auth D]
O [auth E]
G [auth A],
I [auth B],
K [auth C],
M [auth D],
O [auth E],
Q [auth F]
C10 H16 N5 O14 P3
Query on MG

Download Ideal Coordinates CCD File 
H [auth A]
J [auth B]
L [auth C]
N [auth D]
P [auth E]
H [auth A],
J [auth B],
L [auth C],
N [auth D],
P [auth E],
R [auth F]
Experimental Data & Validation

Experimental Data

  • Resolution: 2.20 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.204 
  • R-Value Observed: 0.207 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 56.77α = 90
b = 127.666β = 90
c = 145.031γ = 90
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
HKL-3000data reduction
SCALEPACKdata scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2020-04-15
    Type: Initial release
  • Version 1.1: 2020-08-19
    Changes: Database references, Derived calculations, Structure summary
  • Version 1.2: 2020-08-26
    Changes: Structure summary
  • Version 1.3: 2020-09-16
    Changes: Database references
  • Version 1.4: 2023-10-11
    Changes: Data collection, Database references, Refinement description