4WAF

Crystal Structure of a novel tetrahydropyrazolo[1,5-a]pyrazine in an engineered PI3K alpha

• PDB DOI: https://doi.org/10.2210/pdb4WAF/pdb

• Classification: transferase/transferase inhibitor
• Organism(s): Homo sapiens
• Expression System: Trichoplusia ni
• Mutation(s): Yes 


• Deposited: 2014-08-29 Released: 2014-12-31 
• Deposition Author(s): Knapp, M.S., Elling, R.A.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.39 Å
• R-Value Free: 0.247 
• R-Value Work: 0.199 
• R-Value Observed: 0.202 

Literature

Structure-Based Drug Design of Novel Potent and Selective Tetrahydropyrazolo[1,5-a]pyrazines as ATR Inhibitors.

Barsanti, P.A., Aversa, R.J., Jin, X., Pan, Y., Lu, Y., Elling, R., Jain, R., Knapp, M., Lan, J., Lin, X., Rudewicz, P., Sim, J., Taricani, L., Thomas, G., Xiao, L., Yue, Q.

(2015) ACS Med Chem Lett 6: 37-41

• PubMed: 25589927 
• DOI: https://doi.org/10.1021/ml500353p
• Primary Citation of Related Structures:  
  4WAF


• PubMed Abstract: 
  

  A saturation strategy focused on improving the selectivity and physicochemical properties of ATR inhibitor HTS hit 1 led to a novel series of highly potent and selective tetrahydropyrazolo[1,5-a]pyrazines. Use of PI3Kα mutants as ATR crystal structure surrogates was instrumental in providing cocrystal structures to guide the medicinal chemistry designs. Detailed DMPK studies involving cyanide and GSH as trapping agents during microsomal incubations, in addition to deuterium-labeled compounds as mechanistic probes uncovered the molecular basis for the observed CYP3A4 TDI in the series.

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Organizational Affiliation: 

Global Discovery Chemistry Oncology, Novartis Institutes for Biomedical Research , 5300 Chiron Way, Emeryville, California 94608, United States.

Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 2-mer - A1B1 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 164.31 kDa 
• Atom Count: 10,388 
• Modelled Residue Count: 1,267 
• Deposited Residue Count: 1,396 
• Unique protein chains: 2

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit alpha isoform	A	1,073	Homo sapiens	Mutation(s): 4  Gene Names: PIK3CA EC: 2.7.1.153 (PDB Primary Data), 2.7.11.1 (PDB Primary Data)
UniProt & NIH Common Fund Data Resources
Find proteins for P42336 (Homo sapiens) Explore P42336  Go to UniProtKB:  P42336
PHAROS:  P42336 GTEx:  ENSG00000121879

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
Phosphatidylinositol 3-kinase regulatory subunit alpha	B	323	Homo sapiens	Mutation(s): 1  Gene Names: PIK3R1, GRB1
UniProt & NIH Common Fund Data Resources
Find proteins for P27986 (Homo sapiens) Explore P27986  Go to UniProtKB:  P27986
PHAROS:  P27986 GTEx:  ENSG00000145675

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
3K6	C [auth A]	N,N-dimethyl-4-[(6R)-6-methyl-5-(1H-pyrrolo[2,3-b]pyridin-4-yl)-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazin-3-yl]benzenesulfonamide C22 H24 N6 O2 S UGAYOLUDSWRLMK-OAHLLOKOSA-N

Binding Affinity Annotations
ID	Source	Binding Affinity
3K6	BindingDB:  4WAF	IC50: 1.00e+4 (nM) from 1 assay(s)

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.39 Å
• R-Value Free: 0.247 
• R-Value Work: 0.199 
• R-Value Observed: 0.202 
• Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 104.483	α = 90
b = 106.525	β = 90
c = 133.507	γ = 90

Software Package:

Software Name	Purpose
BUSTER	refinement

Structure Validation

Entry History 

Deposition Data

• Released Date: 2014-12-31 
Deposition Author(s): Knapp, M.S., Elling, R.A.

Revision History  

• Version 1.0: 2014-12-31
  Type: Initial release
  
• Version 1.1: 2015-01-28
  Changes: Database references
• Version 1.2: 2023-09-27
  Changes: Data collection, Database references, Derived calculations, Refinement description, Source and taxonomy