5O2S

Human KRAS in complex with darpin K27


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.22 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.201 
  • R-Value Observed: 0.203 

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Literature

Structural and functional characterization of a DARPin which inhibits Ras nucleotide exchange.

Guillard, S.Kolasinska-Zwierz, P.Debreczeni, J.Breed, J.Zhang, J.Bery, N.Marwood, R.Tart, J.Overman, R.Stocki, P.Mistry, B.Phillips, C.Rabbitts, T.Jackson, R.Minter, R.

(2017) Nat Commun 8: 16111-16111

  • DOI: 10.1038/ncomms16111
  • Primary Citation of Related Structures:  
    5O2S, 5O2T

  • PubMed Abstract: 
  • Ras mutations are the oncogenic drivers of many human cancers and yet there are still no approved Ras-targeted cancer therapies. Inhibition of Ras nucleotide exchange is a promising new approach but better understanding of this mechanism of action is needed ...

    Ras mutations are the oncogenic drivers of many human cancers and yet there are still no approved Ras-targeted cancer therapies. Inhibition of Ras nucleotide exchange is a promising new approach but better understanding of this mechanism of action is needed. Here we describe an antibody mimetic, DARPin K27, which inhibits nucleotide exchange of Ras. K27 binds preferentially to the inactive Ras GDP form with a K d of 4 nM and structural studies support its selectivity for inactive Ras. Intracellular expression of K27 significantly reduces the amount of active Ras, inhibits downstream signalling, in particular the levels of phosphorylated ERK, and slows the growth in soft agar of HCT116 cells. K27 is a potent, non-covalent inhibitor of nucleotide exchange, showing consistent effects across different isoforms of Ras, including wild-type and oncogenic mutant forms.


    Organizational Affiliation

    Antibody Discovery and Protein Engineering, MedImmune, Milstein Building, Granta Park, Cambridge CB21 6GH, UK.



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
GTPase KRasA, C, E, G169Homo sapiensMutation(s): 1 
Gene Names: KRASKRAS2RASK2
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
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Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
darpin K27B, D, F, H178Homo sapiensMutation(s): 0 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.22 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.201 
  • R-Value Observed: 0.203 
  • Space Group: P 65
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 197.14α = 90
b = 197.14β = 90
c = 84.61γ = 120
Software Package:
Software NamePurpose
REFMACrefinement
xia2data reduction
Aimlessdata scaling
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment 



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2017-07-26
    Type: Initial release