1SZM image
Entry Detail
PDB ID:
1SZM
Keywords:
Title:
DUAL BINDING MODE OF BISINDOLYLMALEIMIDE 2 TO PROTEIN KINASE A (PKA)
Biological Source:
Source Organism:
PDB Version:
Deposition Date:
2004-04-06
Release Date:
2004-06-01
Method Details:
Experimental Method:
Resolution:
2.50 Å
R-Value Free:
0.28
R-Value Work:
0.23
R-Value Observed:
0.23
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:cAMP-dependent protein kinase, alpha-catalytic subunit
Mutations:V123A, L173M, Q181K
Chain IDs:A, B
Chain Length:350
Number of Molecules:2
Biological Source:Bos taurus
Modified Residue
Compound ID Chain ID Parent Comp ID Details 2D Image
SEP A SER PHOSPHOSERINE
TPO A THR PHOSPHOTHREONINE
Ligand Molecules
Primary Citation
The protein kinase C inhibitor bisindolyl maleimide 2 binds with reversed orientations to different conformations of protein kinase a.
J.Biol.Chem. 279 23679 23690 (2004)
PMID: 14996846 DOI: 10.1074/jbc.M314082200

Abstact

As the key mediators of eukaryotic signal transduction, the protein kinases often cause disease, and in particular cancer, when disregulated. Appropriately selective protein kinase inhibitors are sought after as research tools and as therapeutic drugs; several have already proven valuable in clinical use. The AGC subfamily protein kinase C (PKC) was identified early as a cause of cancer, leading to the discovery of a variety of PKC inhibitors. Despite its importance and early discovery, no crystal structure for PKC has yet been reported. Therefore, we have co-crystallized PKC inhibitor bisindolyl maleimide 2 (BIM2) with PKA variants to study its binding interactions. BIM2 co-crystallized as an asymmetric pair of kinase-inhibitor complexes. In this asymmetric unit, the two kinase domains have different lobe configurations, and two different inhibitor conformers bind in different orientations. One kinase molecule (A) is partially open with respect to the catalytic conformation, the other (B) represents the most open conformation of PKA reported so far. In monomer A, the BIM2 inhibitor binds tightly via an induced fit in the ATP pocket. The indole moieties are rotated out of the plane with respect to the chemically related but planar inhibitor staurosporine. In molecule B a different conformer of BIM2 binds in a reversed orientation relative to the equivalent maleimide atoms in molecule A. Also, a critical active site salt bridge is disrupted, usually indicating the induction of an inactive conformation. Molecular modeling of the clinical phase III PKC inhibitor LY333531 into the electron density of BIM2 reveals the probable binding mechanism and explains selectivity properties of the inhibitor.

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Primary Citation of related structures