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 35UC | pdb_000035uc

Crystal structure of 2-amino-[1,2,4]triazolo[1,5-a]pyridine derivative bound to KIT


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.33 Å
  • R-Value Free: 
    0.295 (Depositor), 0.298 (DCC) 
  • R-Value Work: 
    0.226 (Depositor), 0.230 (DCC) 

Starting Model: experimental
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wwPDB Validation 3D Report Full Report

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Ligand Structure Quality Assessment 


This is version 1.1 of the entry. See complete history. 

Literature

Leveraging Structure-Based Design to Overcome Class III RTK Off-Target Activity in the Development of Selective Wild-Type KIT Inhibitors.

Moon, H., Yan, X., Zhu, J., Mata, G., Wang, Z., Haelsig, K.T., Schweickert, P.G., Sivick, K.E., Huang, H.T., Van Abbema, A.M., Chen, S., Zhao, X., Green, D.W., Jin, L., Young, S.W., Walters, M.J., Walker, N.P., Leleti, M.R., Powers, J.P., Jeffrey, J.L.

(2026) J Med Chem 69: 21335-21362

  • DOI: https://doi.org/10.1021/acs.jmedchem.6c01334
  • Primary Citation Related Structures: 
    35UA, 35UC

  • PubMed Abstract: 

    Selective KIT inhibition is an effective strategy for treating mast cell-driven diseases, but highly conserved ATP-binding sites in class III RTKs hinder selective inhibitor design. We employed structure-guided medicinal chemistry to optimize a series of potent, selective KIT inhibitors. An initial triazolopyridine hinge-binding motif enabled potent KIT inhibition with high selectivity and, after central linker optimization, led to a "reverse" arylacetamide series with further improved potency and pharmacokinetic properties. Incorporation of a pyrazole-based linker and modification of the hinge-binding motif led to improved potency in the presence of human serum. Further tuning of the terminal aryl substituent mitigated cytochrome P450 time-dependent inhibition and improved kinome selectivity. Crystallography revealed key elements of KIT inhibition and showed that subtle modulation of linker stereoelectronic effects in the gatekeeper region can drive selectivity. These efforts yielded an optimized lead inhibitor with low-nanomolar cellular potency, high KIT selectivity, and properties favorable for chronic therapy.


  • Organizational Affiliation: 
    • Arcus Biosciences, Inc. , Hayward, California94545, United States.

Macromolecule Content 

  • Total Structure Weight: 38.93 kDa 
  • Atom Count: 2,613 
  • Modeled Residue Count: 314 
  • Deposited Residue Count: 339 
  • Unique protein chains: 1

Macromolecules

Find similar proteins by:|  3D Structure
Entity ID: 1
MoleculeChains  Sequence LengthOrganismDetailsImage
Mast/stem cell growth factor receptor KitA [auth AAA]339Homo sapiensMutation(s): 0 
Gene Names: KIT, SCFR
EC: 2.7.10.1
UniProt & NIH Common Fund Data Resources
Find proteins for P10721 (Homo sapiens)
Explore P10721 
Go to UniProtKB:  P10721
PHAROS:  P10721
GTEx:  ENSG00000157404 
Entity Groups
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP10721
Sequence Annotations
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Reference Sequence

Small Molecules

Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
A1DMF
(Subject of Investigation/LOI)

Query on A1DMF



Download:Ideal Coordinates CCD File
B [auth AAA]2-[4-(2-azanyl-[1,2,4]triazolo[1,5-a]pyridin-7-yl)pyrazol-1-yl]-~{N}-(2-fluoranyl-4-methyl-phenyl)ethanamide
C18 H16 F N7 O
KVOZIOCJMCXIMR-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.33 Å
  • R-Value Free:  0.295 (Depositor), 0.298 (DCC) 
  • R-Value Work:  0.226 (Depositor), 0.230 (DCC) 
Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 44.934α = 90
b = 81.168β = 90
c = 99.767γ = 90
Software Package:
Software NamePurpose
autoPROCdata processing
Aimlessdata scaling
TRUNCATEdata processing
REFMACrefinement
XDSdata reduction
MOLREPphasing

Structure Validation

View Full Validation Report



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: 2026-09-16
    Type: Initial release
  • Version 1.1: 2026-11-04
    Changes: Database references