PDBsum entry: 1u32

Hydrolase

PDB id: 1u32

Contents

Protein chain

293 a.a. *

Ligands

OKA

BME ×3

Metals

_MN ×2

Waters ×89

* Residue conservation analysis

PDB id:

1u32

Name:

Hydrolase

Title:

Crystal structure of a protein phosphatase-1: calcineurin hybrid bound to okadaic acid

Structure:

Serine/threonine protein phosphatase pp1-gamma catalytic subunit. Chain: a. Fragment: residues 6-298. Synonym: protein phosphatase-1: calcineurin hybrid, pp-1g, protein phosphatase 1c catalytic subunit. Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: ppp1cc. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.00Å R-factor: 0.218 R-free: 0.254

Authors:

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

Key ref:

J.T.Maynes et al. (2004). Crystal structure and mutagenesis of a protein phosphatase-1:calcineurin hybrid elucidate the role of the beta12-beta13 loop in inhibitor binding. J Biol Chem, 279, 43198-43206. PubMed id: 15280359 DOI: 10.1074/jbc.M407184200

Date:

20-Jul-04 Release date: 17-Aug-04

Protein chain

P36873  (PP1G_HUMAN) -  Serine/threonine-protein phosphatase PP1-gamma catalytic subunit

Seq: 323 a.a.

Struc: 293 a.a.*

* PDB and UniProt seqs differ at 5 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.3.1.3.16 - Phosphoprotein phosphatase.
• Reaction: A phosphoprotein + H₂O = a protein + phosphate

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

 Gene Ontology (GO) functional annotation 

• Cellular component: protein complex (10 terms)
• Biological process: cell cycle (4 terms)
• Biochemical function: protein binding (6 terms)

Added reference

DOI no: 10.1074/jbc.M407184200

J Biol Chem 279:43198-43206 (2004)

PubMed id: 15280359

Crystal structure and mutagenesis of a protein phosphatase-1:calcineurin hybrid elucidate the role of the beta12-beta13 loop in inhibitor binding.

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

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.

Selected figure(s)

Figure 2.
FIG. 2. A, stereo representation of the active site of the PP-1c-loop·OA complex showing pertinent active site residues. The inhibitor is shown with yellow carbons. The numbering of active site residues is the same as wild-type PP-1c. B, active site contacts seen the PP-1c-loop·OA complex. OA is shown as a linear representation. All contacts within 4 Å are shown and potential hydrogen bonding interactions have their distances shown.

Figure 7.
FIG. 7. A, stereo representation of the overlay between wild-type PP-1c:OA (red), PP-1c-loop:OA (blue), and calcineurin (orange). Phe^276 (PP-1c, or equivalent) is shown as sticks. B, alignment of PP-1c (red) bound to OA (carbon atoms colored orange) with PP-1c-loop mutant (blue) bound to OA (carbon atoms colored light blue).

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2004, 279, 43198-43206) copyright 2004.

Figures were selected by an automated process.