Crystal Structure of the Kinase domain of Human B-raf with a [1,3]thiazolo[5,4-b]pyridine derivative

Experimental Data Snapshot

  • Resolution: 3.15 Å
  • R-Value Free: 0.243 
  • R-Value Work: 0.196 
  • R-Value Observed: 0.198 

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Design and synthesis of novel DFG-out RAF/vascular endothelial growth factor receptor 2 (VEGFR2) inhibitors. 1. Exploration of [5,6]-fused bicyclic scaffolds.

Okaniwa, M.Hirose, M.Imada, T.Ohashi, T.Hayashi, Y.Miyazaki, T.Arita, T.Yabuki, M.Kakoi, K.Kato, J.Takagi, T.Kawamoto, T.Yao, S.Sumita, A.Tsutsumi, S.Tottori, T.Oki, H.Sang, B.C.Yano, J.Aertgeerts, K.Yoshida, S.Ishikawa, T.

(2012) J Med Chem 55: 3452-3478

  • DOI: https://doi.org/10.1021/jm300126x
  • Primary Citation of Related Structures:  
    3VNT, 4DBN

  • PubMed Abstract: 

    To develop RAF/VEGFR2 inhibitors that bind to the inactive DFG-out conformation, we conducted structure-based drug design using the X-ray cocrystal structures of BRAF, starting from an imidazo[1,2-b]pyridazine derivative. We designed various [5,6]-fused bicyclic scaffolds (ring A, 1-6) possessing an anilide group that forms two hydrogen bond interactions with Cys532. Stabilizing the planarity of this anilide and the nitrogen atom on the six-membered ring of the scaffold was critical for enhancing BRAF inhibition. The selected [1,3]thiazolo[5,4-b]pyridine derivative 6d showed potent inhibitory activity in both BRAF and VEGFR2. Solid dispersion formulation of 6d (6d-SD) maximized its oral absorption in rats and showed significant suppression of ERK1/2 phosphorylation in an A375 melanoma xenograft model in rats by single administration. Tumor regression (T/C = -7.0%) in twice-daily repetitive studies at a dose of 50 mg/kg in rats confirmed that 6d is a promising RAF/VEGFR2 inhibitor showing potent anticancer activity.

  • Organizational Affiliation

    Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-Higashi 2-Chome, Fujisawa, Kanagawa 251-8555, Japan. masanori.okaniwa@takeda.com

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Serine/threonine-protein kinase B-raf
A, B
284Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for P15056 (Homo sapiens)
Explore P15056 
Go to UniProtKB:  P15056
PHAROS:  P15056
GTEx:  ENSG00000157764 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP15056
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on 0JA

Download Ideal Coordinates CCD File 
C [auth A],
D [auth B]
C27 H19 Cl F N5 O3 S
Binding Affinity Annotations 
IDSourceBinding Affinity
0JA PDBBind:  4DBN IC50: 7 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Resolution: 3.15 Å
  • R-Value Free: 0.243 
  • R-Value Work: 0.196 
  • R-Value Observed: 0.198 
  • Space Group: P 41 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 111.04α = 90
b = 111.04β = 90
c = 146.844γ = 90
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
HKL-2000data collection
HKL-2000data reduction
HKL-2000data 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: 2012-04-11
    Type: Initial release
  • Version 1.1: 2012-06-13
    Changes: Database references
  • Version 1.2: 2024-02-28
    Changes: Data collection, Database references, Derived calculations