3ECM

Crystal structure of the unliganded PDE8A catalytic domain


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.265 
  • R-Value Work: 0.236 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Kinetic and structural studies of phosphodiesterase-8A and implication on the inhibitor selectivity

Wang, H.Yan, Z.Yang, S.Cai, J.Robinson, H.Ke, H.

(2008) Biochemistry 47: 12760-12768

  • DOI: 10.1021/bi801487x
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Cyclic nucleotide phosphodiesterase-8 (PDE8) is a family of cAMP-specific enzymes and plays important roles in many biological processes, including T-cell activation, testosterone production, adrenocortical hyperplasia, and thyroid function. However, ...

    Cyclic nucleotide phosphodiesterase-8 (PDE8) is a family of cAMP-specific enzymes and plays important roles in many biological processes, including T-cell activation, testosterone production, adrenocortical hyperplasia, and thyroid function. However, no PDE8 selective inhibitors are available for trial treatment of human diseases. Here we report kinetic properties of the highly active PDE8A1 catalytic domain prepared from refolding and its crystal structures in the unliganded and 3-isobutyl-1-methylxanthine (IBMX) bound forms at 1.9 and 2.1 A resolutions, respectively. The PDE8A1 catalytic domain has a K(M) of 1.8 microM, V(max) of 6.1 micromol/min/mg, a k(cat) of 4.0 s(-1) for cAMP, and a K(M) of 1.6 mM, V(max) of 2.5 micromol/min/mg, a k(cat) of 1.6 s(-1) for cGMP, thus indicating that the substrate specificity of PDE8 is dominated by K(M). The structure of the PDE8A1 catalytic domain has similar topology as those of other PDE families but contains two extra helices around Asn685-Thr710. Since this fragment is distant from the active site of the enzyme, its impact on the catalysis is unclear. The PDE8A1 catalytic domain is insensitive to the IBMX inhibition (IC(50) = 700 microM). The unfavorable interaction of IBMX in the PDE8A1-IBMX structure suggests an important role of Tyr748 in the inhibitor binding. Indeed, the mutation of Tyr748 to phenylalanine increases the PDE8A1 sensitivity to several nonselective or family selective PDE inhibitors. Thus, the structural and mutagenesis studies provide not only insight into the enzymatic properties but also guidelines for design of PDE8 selective inhibitors.


    Organizational Affiliation

    Department of Biochemistry and Biophysics, Lineberger Comprehensive Cancer Center, The University of North Carolina, Chapel Hill, North Carolina 27599-7260, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
High affinity cAMP-specific and IBMX-insensitive 3',5'-cyclic phosphodiesterase 8A
A
338Homo sapiensMutation(s): 0 
Gene Names: PDE8A
EC: 3.1.4.53
Find proteins for O60658 (Homo sapiens)
Go to Gene View: PDE8A
Go to UniProtKB:  O60658
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ZN
Query on ZN

Download SDF File 
Download CCD File 
A
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
MG
Query on MG

Download SDF File 
Download CCD File 
A
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.265 
  • R-Value Work: 0.236 
  • Space Group: C 2 2 21
Unit Cell:
Length (Å)Angle (°)
a = 76.261α = 90.00
b = 132.661β = 90.00
c = 101.517γ = 90.00
Software Package:
Software NamePurpose
ADSCdata collection
HKL-2000data scaling
HKL-2000data reduction
CNSrefinement
AMoREphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2008-11-25
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance