6C0U

Crystal structure of cAMP-dependent protein kinase Calpha subunit bound with N46


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.65 Å
  • R-Value Free: 0.243 
  • R-Value Work: 0.208 
  • R-Value Observed: 0.211 

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Ligand Structure Quality Assessment 


This is version 1.4 of the entry. See complete history


Literature

Structural basis for selective inhibition of human PKG I alpha by the balanol-like compound N46.

Qin, L.Sankaran, B.Aminzai, S.Casteel, D.E.Kim, C.

(2018) J Biol Chem 293: 10985-10992

  • DOI: https://doi.org/10.1074/jbc.RA118.002427
  • Primary Citation of Related Structures:  
    6C0T, 6C0U

  • PubMed Abstract: 

    Activation of protein kinase G (PKG) Iα in nociceptive neurons induces long-term hyperexcitability that causes chronic pain. Recently, a derivative of the fungal metabolite balanol, N46, has been reported to inhibit PKG Iα with high potency and selectivity and attenuate thermal hyperalgesia and osteoarthritic pain. Here we determined co-crystal structures of the PKG Iα C-domain and cAMP-dependent protein kinase (PKA) Cα, each bound with N46, at 1.98 Å and 2.65 Å, respectively. N46 binds the active site with its external phenyl ring, specifically interacting with the glycine-rich loop and the αC helix. Phe-371 at the PKG Iα glycine-rich loop is oriented parallel to the phenyl ring of N46, forming a strong π-stacking interaction, whereas the analogous Phe-54 in PKA Cα rotates 30° and forms a weaker interaction. Structural comparison revealed that steric hindrance between the preceding Ser-53 and the propoxy group of the phenyl ring may explain the weaker interaction with PKA Cα. The analogous Gly-370 in PKG Iα, however, causes little steric hindrance with Phe-371. Moreover, Ile-406 on the αC helix forms a hydrophobic interaction with N46 whereas its counterpart in PKA, Thr-88, does not. Substituting these residues in PKG Iα with those in PKA Cα increases the IC 50 values for N46, whereas replacing these residues in PKA Cα with those in PKG Iα reduces the IC 50 , consistent with our structural findings. In conclusion, our results explain the structural basis for N46-mediated selective inhibition of human PKG Iα and provide a starting point for structure-guided design of selective PKG Iα inhibitors.


  • Organizational Affiliation

    From the Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
cAMP-dependent protein kinase catalytic subunit alpha354Homo sapiensMutation(s): 0 
Gene Names: PRKACAPKACA
EC: 2.7.11.11
UniProt & NIH Common Fund Data Resources
Find proteins for P17612 (Homo sapiens)
Explore P17612 
Go to UniProtKB:  P17612
PHAROS:  P17612
GTEx:  ENSG00000072062 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP17612
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Modified Residues  2 Unique
IDChains TypeFormula2D DiagramParent
SEP
Query on SEP
A
L-PEPTIDE LINKINGC3 H8 N O6 PSER
TPO
Query on TPO
A
L-PEPTIDE LINKINGC4 H10 N O6 PTHR
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.65 Å
  • R-Value Free: 0.243 
  • R-Value Work: 0.208 
  • R-Value Observed: 0.211 
  • Space Group: P 31 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 120.494α = 90
b = 120.494β = 90
c = 80.81γ = 120
Software Package:
Software NamePurpose
PHENIXrefinement
iMOSFLMdata reduction
Aimlessdata scaling
PHENIXphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United States5R01GM090161-08

Revision History  (Full details and data files)

  • Version 1.0: 2018-05-30
    Type: Initial release
  • Version 1.1: 2018-07-25
    Changes: Data collection, Database references
  • Version 1.2: 2019-02-20
    Changes: Author supporting evidence, Data collection
  • Version 1.3: 2020-01-01
    Changes: Author supporting evidence
  • Version 1.4: 2023-10-04
    Changes: Data collection, Database references, Refinement description