The Structure of the Bovine Protein Tyrosine Phosphatase Dimer Reveals a Potential Self-Regulation Mechanism<sup>,</sup>

Tabernero, Lydia; Evans, B.; Tishmack, P.A.; Etten, Robert L. Van; Stauffacher, Cynthia V.

doi:10.1021/bi990381x

Cited by 34 publications

(62 citation statements)

References 29 publications

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“…Previous crystal structural analyses revealed that several conserved residues, including Asn-15, Ser-19, Ser-43, and His-72, are involved in the stabilization of the P-loop of BPTP. 8,11 This is supported by the present dynamics simulations. His-72 participates in hydrogen …”

Section: Figuresupporting

confidence: 85%

“…Overall, the structure of the unligated enzymes (both the wildtype and C12S mutant) showed minimal variations in comparison with the X-ray structure, which contains a phosphate ion as substrate. 8,11,12,46 The rms deviations between the two structures are 1.0 Å for all heavy atoms and 0.7 Å for the backbone heavy atoms in the wild-type enzyme. The backbone heavy atoms in the P-loop (residues 12-19) region only have an average deviation of 0.3 Å in comparison with the ligated X-ray structure.…”

Section: The Wild-type Enzyme and C12s Mutantmentioning

confidence: 94%

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Hydrogen-bonding interactions in the active site of a low molecular weight protein-tyrosine phosphatase

Alhambra

Gao

2000

J. Comput. Chem.

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Molecular dynamics simulation of the Michaelis complex, phospho-enzyme intermediate, and the wild-type and C12S mutant have been carried out to examine hydrogen-bonding interactions in the active site of the bovine low molecular weight protein-tyrosine phosphatase (BPTP). It was found that the S γ atom of the nucleophilic residue Cys-12 is ideally located at a position opposite from the phenylphosphate dianion for an inline nucleophilic substitution reaction. In addition, electrostatic and hydrogen-bonding interactions from the backbone amide groups of the phosphate-binding loop strongly stabilize the thiolate anion, making Cys-12 ionized in the active site. In the phospho-enzyme intermediate, three water molecules are found to form strong hydrogen bonds with the phosphate group. In addition, another water molecule can be identified to form bridging hydrogen bonds between the phosphate group and Asp-129, which may act as the nucleophile in the subsequent phosphate hydrolysis reaction, with Asp-129 serving as a general base. The structural difference at the active site between the wild-type and C12S mutant has been examined. It was found that the alkoxide anion is significantly shifted toward one side of the phosphate binding loop, away from the optimal position enjoyed by the thiolate anion of the wild-type enzyme in an S N 2 process. This, coupled with the high pK a value of an alcoholic residue, makes the C12S mutant catalytically inactive. These molecular dynamics simulations provided details of hydrogen bonding interactions in the active site of BPTP, and a structural basis for further studies using combined quantum mechanical and molecular mechanical potential to model the entire dephosphorylation reaction by BPTP.

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Section: Figuresupporting

confidence: 85%

Section: The Wild-type Enzyme and C12s Mutantmentioning

confidence: 94%

Hydrogen-bonding interactions in the active site of a low molecular weight protein-tyrosine phosphatase

Alhambra

Gao

2000

J. Comput. Chem.

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“…Because the compound binds to the enzymesubstrate complex, it may assist in trapping endogenous substrate in the active site of the enzyme in inhibitor-treated cells. Furthermore, if PTPMT1 does indeed exist as a dimer, the compound may also prove useful in efforts to study the enzyme's structure using X-ray crystallography by stabilizing the dimer (Tabernero et al, 1999).…”

Section: Discussionmentioning

confidence: 99%

Pharmacological Targeting of the Mitochondrial Phosphatase PTPMT1

Doughty-Shenton

Joseph

Zhang

et al. 2010

J Pharmacol Exp Ther

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The dual-specificity protein tyrosine phosphatases (PTPs) play integral roles in the regulation of cell signaling. There is a need for new tools to study these phosphatases, and the identification of inhibitors potentially affords not only new means for their study, but also possible therapeutics for the treatment of diseases caused by their dysregulation. However, the identification of selective inhibitors of the protein phosphatases has proven somewhat difficult. PTP localized to mitochondrion 1 (PTPMT1) is a recently discovered dual-specificity phosphatase that has been implicated in the regulation of insulin secretion. Screening of a commercially available small-molecule library yielded alexidine dihydrochloride, a dibiguanide compound, as an effective and selective inhibitor of PTPMT1 with an in vitro concentration that inhibits response by 50% of 1.08 M. A related dibiguanide analog, chlorhexidine dihydrochloride, also significantly inhibited PTPMT1, albeit with lower potency, while a monobiguanide analog showed very weak inhibition. Treatment of isolated rat pancreatic islets with alexidine dihydrochloride resulted in a dosedependent increase in insulin secretion, whereas treatment of a pancreatic ␤-cell line with the drug affected the phosphorylation of mitochondrial proteins in a manner similar to genetic inhibition of PTPMT1. Furthermore, knockdown of PTPMT1 in rat islets rendered them insensitive to alexidine dihydrochloride treatment, providing evidence for mechanism-based activity of the inhibitor. Taken together, these studies establish alexidine dihydrochloride as an effective inhibitor of PTPMT1, both in vitro and in cells, and support the notion that PTPMT1 could serve as a pharmacological target in the treatment of type II diabetes.

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“…The crystal structure of bovine PTPase (bPTPase) (PDB ID: 1DG9) has been resolved at 1.90 Å [51], which shows about 41% sequence identities and shares a common signature motif C(X) 5 R(S/T) with PTPase. The structure of 1DG9 reveals a dimer formed by Tyr131 and Tyr132 from two different monomers at pH 7.0 in 0.1 M Tris.…”

Section: Discussionmentioning

confidence: 99%

Inactivation and Unfolding of Protein Tyrosine Phosphatase from Thermus thermophilus HB27 during Urea and Guanidine Hydrochloride Denaturation

Wang

Liu

et al. 2014

PLoS ONE

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The effects of urea and guanidine hydrochloride (GdnHCl) on the activity, conformation and unfolding process of protein tyrosine phosphatase (PTPase), a thermostable low molecular weight protein from Thermus thermophilus HB27, have been studied. Enzymatic activity assays showed both urea and GdnHCl resulted in the inactivation of PTPase in a concentration and time-dependent manner. Inactivation kinetics analysis suggested that the inactivation of PTPase induced by urea and GdnHCl were both monophasic and reversible processes, and the effects of urea and GdnHCl on PTPase were similar to that of mixed-type reversible inhibitors. Far-ultraviolet (UV) circular dichroism (CD), Tryptophan and 1-anilinonaphthalene -8-sulfonic acid (ANS) fluorescence spectral analyses indicated the existence of a partially active and an inactive molten globule-like intermediate during the unfolding processes induced by urea and GdnHCl, respectively. Based on the sequence alignment and the homolog Tt1001 protein structure, we discussed the possible conformational transitions of PTPase induced by urea and GdnHCl and compared the conformations of these unfolding intermediates with the transient states in bovine PTPase and its complex structures in detail. Our results may be able to provide some valuable clues to reveal the relationship between the structure and enzymatic activity, and the unfolding pathway and mechanism of PTPase.

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The Structure of the Bovine Protein Tyrosine Phosphatase Dimer Reveals a Potential Self-Regulation Mechanism^,

Cited by 34 publications

References 29 publications

Hydrogen-bonding interactions in the active site of a low molecular weight protein-tyrosine phosphatase

Hydrogen-bonding interactions in the active site of a low molecular weight protein-tyrosine phosphatase

Pharmacological Targeting of the Mitochondrial Phosphatase PTPMT1

Inactivation and Unfolding of Protein Tyrosine Phosphatase from Thermus thermophilus HB27 during Urea and Guanidine Hydrochloride Denaturation

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The Structure of the Bovine Protein Tyrosine Phosphatase Dimer Reveals a Potential Self-Regulation Mechanism,

Cited by 34 publications

References 29 publications

Hydrogen-bonding interactions in the active site of a low molecular weight protein-tyrosine phosphatase

Hydrogen-bonding interactions in the active site of a low molecular weight protein-tyrosine phosphatase

Pharmacological Targeting of the Mitochondrial Phosphatase PTPMT1

Inactivation and Unfolding of Protein Tyrosine Phosphatase from Thermus thermophilus HB27 during Urea and Guanidine Hydrochloride Denaturation

Contact Info

Product

Resources

About

The Structure of the Bovine Protein Tyrosine Phosphatase Dimer Reveals a Potential Self-Regulation Mechanism^,