Biological Assembly 1  

 3D View: Structure | Electron Density | Ligand Interaction

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 34.92 kDa 
• Atom Count: 2531 
• Modelled Residue Count: 293 
• Deposited Residue Count: 293 
• Unique protein chains: 1

1U32

Crystal structure of a Protein Phosphatase-1: Calcineurin Hybrid Bound to Okadaic Acid

• DOI: 10.2210/pdb1U32/pdb

• Classification: HYDROLASE
• Organism(s): Homo sapiens
• Expression System: Escherichia coli
• Mutation(s): Yes 


• Deposited: 2004-07-20 Released: 2004-08-17 
• Deposition Author(s): Maynes, J.T., Perreault, K.R., Cherney, M.M., Luu, H.A., James, M.N.G., Holmes, C.F.B.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.00 Å
• R-Value Free: 0.254 
• R-Value Work: 0.218 
• R-Value Observed: 0.218 

Literature

Crystal Structure and Mutagenesis of a Protein Phosphatase-1:Calcineurin Hybrid Elucidate the Role of the {beta}12-{beta}13 Loop in Inhibitor Binding

Maynes, J.T., Perreault, K.R., Cherney, M.M., Luu, H.A., James, M.N.G., Holmes, C.F.B.

(2004) J Biol Chem 279: 43198-43206

• PubMed: 15280359 
• DOI: 10.1074/jbc.M407184200
• Primary Citation of Related Structures:  
  1U32


• PubMed Abstract: 
  

Protein phosphatase-1 and protein phosphatase-2B (calcineurin) are eukaryotic serine/threonine phosphatases that share 40% sequence identity in their catalytic subunits. Despite the similarities in sequence, these phosphatases are widely divergent when it comes to inhibition by natural product toxins, such as microcystin-LR and okadaic acid. The most prominent region of non-conserved sequence between these phosphatases corresponds to the beta12-beta13 loop of protein phosphatase-1, and the L7 loop of toxin-resistant calcineurin. In the present study, mutagenesis of residues 273-277 of the beta12-beta13 loop of the protein phosphatase-1 catalytic subunit (PP-1c) to the corresponding residues in calcineurin (312-316), resulted in a chimeric mutant that showed a decrease in sensitivity to microcystin-LR, okadaic acid, and the endogenous PP-1c inhibitor protein inhibitor-2. A crystal structure of the chimeric mutant in complex with okadaic acid was determined to 2.0-A resolution. The beta12-beta13 loop region of the mutant superimposes closely with that of wild-type PP-1c bound to okadaic acid. Systematic mutation of each residue in the beta12-beta13 loop of PP-1c showed that a single amino acid change (C273L) was the most influential in mediating sensitivity of PP-1c to toxins. Taken together, these data indicate that it is an individual amino acid residue substitution and not a change in the overall beta12-beta13 loop conformation of protein phosphatase-1 that contributes to disrupting important interactions with inhibitors such as microcystin-LR and okadaic acid.

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Organizational Affiliation: 

Canadian Institutes of Health Research, Group in Protein Structure and Function, Department of Biochemistry, Faculty of Medicine, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Serine/threonine protein phosphatase PP1-gamma catalytic subunit	A	293	Homo sapiens	Mutation(s): 5  Gene Names: PPP1CC EC: 3.1.3.16
UniProt & NIH Common Fund Data Resources
Find proteins for P36873 (Homo sapiens) Explore P36873  Go to UniProtKB:  P36873
PHAROS:  P36873 GTEx:  ENSG00000186298

Small Molecules

Ligands 3 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
OKA (Subject of Investigation/LOI)	D [auth A]	OKADAIC ACID C44 H68 O13 QNDVLZJODHBUFM-WFXQOWMNSA-N
BME	E [auth A], F [auth A], G [auth A]	BETA-MERCAPTOETHANOL C2 H6 O S DGVVWUTYPXICAM-UHFFFAOYSA-N
MN	B [auth A], C [auth A]	MANGANESE (II) ION Mn WAEMQWOKJMHJLA-UHFFFAOYSA-N

Binding Affinity Annotations
ID	Source	Binding Affinity
OKA	PDBBind:  1U32	IC50: 97 (nM) from 1 assay(s)
	BindingDB:  1U32	IC50: min: 20, max: 5000 (nM) from 8 assay(s)
	Binding MOAD:  1U32	IC50: 97 (nM) from 1 assay(s)

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.00 Å
• R-Value Free: 0.254 
• R-Value Work: 0.218 
• R-Value Observed: 0.218 
• Space Group: P 4₂ 2₁ 2

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 98.759	α = 90
b = 98.759	β = 90
c = 62.18	γ = 90

Software Package:

Software Name	Purpose
CNS	refinement
DENZO	data reduction
SCALEPACK	data scaling
AMoRE	phasing

Structure Validation

Ligand Structure Quality Assessment  

Entry History 

Deposition Data

• Deposited Date: 2004-07-20 
• Released Date: 2004-08-17 
Deposition Author(s): Maynes, J.T., Perreault, K.R., Cherney, M.M., Luu, H.A., James, M.N.G., Holmes, C.F.B.

Revision History  

• Version 1.0: 2004-08-17
  Type: Initial release
  
• Version 1.1: 2008-04-30
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance