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Cross M, Rajan S, Chekaiban J, Saunders J, Hamilton C, Kim JS, Coster MJ, Gasser RB, Hofmann A. Enzyme characteristics of pathogen-specific trehalose-6-phosphate phosphatases. Sci Rep 2017; 7:2015. [PMID: 28515463 PMCID: PMC5435700 DOI: 10.1038/s41598-017-02220-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 04/07/2017] [Indexed: 12/21/2022] Open
Abstract
Owing to the key role of trehalose in pathogenic organisms, there has recently been growing interest in trehalose metabolism for therapeutic purposes. Trehalose-6-phosphate phosphatase (TPP) is a pivotal enzyme in the most prominent biosynthesis pathway (OtsAB). Here, we compare the enzyme characteristics of recombinant TPPs from five important nematode and bacterial pathogens, including three novel members of this protein family. Analysis of the kinetics of trehalose-6-phosphate hydrolysis reveals that all five enzymes display a burst-like kinetic behaviour which is characterised by a decrease of the enzymatic rate after the pre-steady state. The observed super-stoichiometric burst amplitudes can be explained by multiple global conformational changes in members of this enzyme family during substrate processing. In the search for specific TPP inhibitors, the trapping of the complex conformational transitions in TPPs during the catalytic cycle may present a worthwhile strategy to explore.
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Affiliation(s)
- Megan Cross
- Griffith Institute for Drug Discovery, Griffith University, Nathan, Queensland, 4111, Australia
| | - Siji Rajan
- Griffith Institute for Drug Discovery, Griffith University, Nathan, Queensland, 4111, Australia
| | - Janine Chekaiban
- Griffith Institute for Drug Discovery, Griffith University, Nathan, Queensland, 4111, Australia
| | - Jake Saunders
- Griffith Institute for Drug Discovery, Griffith University, Nathan, Queensland, 4111, Australia
| | - Chloe Hamilton
- Griffith Institute for Drug Discovery, Griffith University, Nathan, Queensland, 4111, Australia
| | - Jeong-Sun Kim
- Department of Chemistry, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - Mark J Coster
- Griffith Institute for Drug Discovery, Griffith University, Nathan, Queensland, 4111, Australia
| | - Robin B Gasser
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Andreas Hofmann
- Griffith Institute for Drug Discovery, Griffith University, Nathan, Queensland, 4111, Australia.
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, 3010, Australia.
- Queensland Tropical Health Alliance, Smithfield, Queensland, 4878, Australia.
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2
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Retegan M, Milet A, Jamet H. Comparative Theoretical Studies of the Phosphomonoester Hydrolysis Mechanism by Purple Acid Phosphatases. J Phys Chem A 2010; 114:7110-6. [DOI: 10.1021/jp100478f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- M. Retegan
- DCM, Equipe Chimie Théorique, UMR CNRS 5250, ICMG, FR CNRS, Université J. Fourier, BP. 53, 38041 Grenoble Cedex, France
| | - A. Milet
- DCM, Equipe Chimie Théorique, UMR CNRS 5250, ICMG, FR CNRS, Université J. Fourier, BP. 53, 38041 Grenoble Cedex, France
| | - H. Jamet
- DCM, Equipe Chimie Théorique, UMR CNRS 5250, ICMG, FR CNRS, Université J. Fourier, BP. 53, 38041 Grenoble Cedex, France
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3
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Moraxella catarrhalis synthesizes an autotransporter that is an acid phosphatase. J Bacteriol 2007; 190:1459-72. [PMID: 18065547 DOI: 10.1128/jb.01688-07] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Moraxella catarrhalis O35E was shown to synthesize a 105-kDa protein that has similarity to both acid phosphatases and autotransporters. The N-terminal portion of the M. catarrhalis acid phosphatase A (MapA) was most similar (the BLAST probability score was 10(-10)) to bacterial class A nonspecific acid phosphatases. The central region of the MapA protein had similarity to passenger domains of other autotransporter proteins, whereas the C-terminal portion of MapA resembled the translocation domain of conventional autotransporters. Cloning and expression of the M. catarrhalis mapA gene in Escherichia coli confirmed the presence of acid phosphatase activity in the MapA protein. The MapA protein was shown to be localized to the outer membrane of M. catarrhalis and was not detected either in the soluble cytoplasmic fraction from disrupted M. catarrhalis cells or in the spent culture supernatant fluid from M. catarrhalis. Use of the predicted MapA translocation domain in a fusion construct with the passenger domain from another predicted M. catarrhalis autotransporter confirmed the translocation ability of this MapA domain. Inactivation of the mapA gene in M. catarrhalis strain O35E reduced the acid phosphatase activity expressed by this organism, and this mutation could be complemented in trans with the wild-type mapA gene. Nucleotide sequence analysis of the mapA gene from six M. catarrhalis strains showed that this protein was highly conserved among strains of this pathogen. Site-directed mutagenesis of a critical histidine residue (H233A) in the predicted active site of the acid phosphatase domain in MapA eliminated acid phosphatase activity in the recombinant MapA protein. This is the first description of an autotransporter protein that expresses acid phosphatase activity.
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4
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Funhoff EG, de Jongh TE, Averill BA. Direct observation of multiple protonation states in recombinant human purple acid phosphatase. J Biol Inorg Chem 2005; 10:550-63. [PMID: 16096803 DOI: 10.1007/s00775-005-0001-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2004] [Accepted: 05/25/2005] [Indexed: 11/28/2022]
Abstract
To date, most spectroscopic studies on mammalian purple acid phosphatases (PAPs) have been performed at a single pH, typically pH 5. The catalytic activity of these enzymes is, however, pH dependent, with optimal pH values of 5.5-6.2 (depending on the form). For example, the pH optimum of PAPs isolated as single polypeptides is around pH 5.5, which is substantially lower that of proteolytically cleaved PAPs (ca. pH 6.2). In addition, the catalytic activity of single polypeptide PAPs at their optimal pH values is four to fivefold lower than that of the proteolytically cleaved enzymes. In order to elucidate the chemical basis for the pH dependence of these enzymes, the spectroscopic properties of both the single polypeptide and proteolytically cleaved forms of recombinant human PAP (recHPAP) and their complexes with inhibitory anions have been examined over the pH range 4 to 8. The EPR spectra of both forms of recHPAP are pH dependent and show the presence of three species: an inactive low pH form (pH<pK( a,1)), an active form (pK( a,1)<pH<pK( a,2)), and an inactive high pH form (pH>pK( a,2)). The pK( a,1) values observed by EPR for the single polypeptide and proteolytically cleaved forms are similar to those previously observed in kinetics studies. The spectroscopic properties of the enzyme-phosphate complex (which should mimic the enzyme-substrate complex), the enzyme-fluoride complex, and the enzyme-fluoride-phosphate complex (which should mimic the ternary enzyme-substrate-hydroxide complex) were also examined. EPR spectra show that phosphate binds to the diiron center of the proteolytically cleaved form of the enzyme, but not to that of the single polypeptide form. EPR spectra also show that fluoride binds only to the low pH form of the enzymes, in which it presumably replaces a coordinated water molecule. The binding of fluoride and phosphate to form a ternary complex appears to be cooperative.
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Affiliation(s)
- Enrico G Funhoff
- Swammerdam Institute for Life Sciences, University of Amsterdam, Plantage Muidergracht 12, 1018 Amsterdam, The Netherlands
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5
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6
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Hengge AC. Mechanistic studies on enzyme-catalyzed phosphoryl transfer. ADVANCES IN PHYSICAL ORGANIC CHEMISTRY 2005. [DOI: 10.1016/s0065-3160(05)40002-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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7
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Reilly TJ, Chance DL, Smith AL. Outer membrane lipoprotein e (P4) of Haemophilus influenzae is a novel phosphomonoesterase. J Bacteriol 1999; 181:6797-805. [PMID: 10542183 PMCID: PMC94146 DOI: 10.1128/jb.181.21.6797-6805.1999] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/1999] [Accepted: 08/10/1999] [Indexed: 11/20/2022] Open
Abstract
Haemophilus influenzae exists as a commensal of the upper respiratory tract of humans but also causes infections of contiguous structures. We describe the identification, localization, purification, and characterization of a novel, surface-localized phosphomonoesterase from a nontypeable H. influenzae strain, R2866. Sequences obtained from two CNBr-derived fragments of this protein matched lipoprotein e (P4) within the H. influenzae sequence database. Escherichia coli DH5alpha transformed with plasmids containing the H. influenzae hel gene, which encodes lipoprotein e (P4), produced high levels of a membrane-associated phosphomonoesterase. The isolated approximately 28-kDa enzyme was tartrate resistant and displayed narrow substrate specificity with the highest activity for arylphosphates, excluding 5-bromo-4-chloro-3-indolylphosphate. Optimum enzymatic activity was observed at pH 5.0 and only in the presence of divalent copper. The enzyme was inhibited by vanadate, molybdate, and EDTA but was resistant to inorganic phosphate. The association of phosphomonoesterase activity with a protein that has also been recognized as a heme transporter suggests a unique role for this unusual phosphohydrolase.
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Affiliation(s)
- T J Reilly
- Department of Molecular Microbiology and Immunology, University of Missouri Medical School, Columbia, Missouri 65212, USA
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Lindqvist Y, Johansson E, Kaija H, Vihko P, Schneider G. Three-dimensional structure of a mammalian purple acid phosphatase at 2.2 A resolution with a mu-(hydr)oxo bridged di-iron center. J Mol Biol 1999; 291:135-47. [PMID: 10438611 DOI: 10.1006/jmbi.1999.2962] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The crystal structure of purple acid phosphatase from rat bone has been determined by molecular replacement and the structure has been refined to 2.2 A resolution to an R -factor of 21.3 % (R -free 26.5 %). The core of the enzyme consists of two seven-stranded mixed beta-sheets, with each sheet flanked by solvent-exposed alpha-helices on one side. The two sheets pack towards each other forming a beta-sandwich. The di-iron center, located at the bottom of the active-site pocket at one edge of the beta-sandwich, contains a mu-hydroxo or mu-oxo bridge and both metal ions are observed in an almost perfect octahedral coordination geometry. The electron density map indicates that a mu-(hydr)oxo bridge is found in the metal center and that at least one solvent molecule is located in the first coordination sphere of one of the metal ions. The crystallographic study of rat purple acid phosphatase reveals that the mammalian enzymes are very similar in overall structure to the plant enzymes in spite of only 18 % overall sequence identity. In particular, coordination and geometry of the iron cluster is preserved in both enzymes and comparison of the active-sites suggests a common mechanism for the mammalian and plant enzymes. However, significant differences are found in the architecture of the substrate binding pocket.
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Affiliation(s)
- Y Lindqvist
- Department of Medical Biochemistry & Biophysics, Karolinska Institutet, Stockholm, S-171 77, Sweden.
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9
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Merkx M, Pinkse MW, Averill BA. Evidence for nonbridged coordination of p-nitrophenyl phosphate to the dinuclear Fe(III)-M(II) center in bovine spleen purple acid phosphatase during enzymatic turnover. Biochemistry 1999; 38:9914-25. [PMID: 10433698 DOI: 10.1021/bi9904454] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The pH dependence of the catalytic parameters k(cat) and K(M) has been determined for the Fe(III)Fe(II)- and Fe(III)Zn(II)-forms of bovine spleen purple acid phosphatase (BSPAP). The parameter k(cat) was found to be maximal at pH 6.3, and a pK(a) of 5.4-5.5 was obtained for the acidic limb of the k(cat) vs pH profile. Two different EPR spectra were detected for the phosphate complex of the mixed-valent diiron enzyme; their relative amounts depended on the pH, with an apparent pK(a) of 6. The EPR spectra of Fe(III)Fe(II)-BSPAP.PO(4) and Fe(III)Zn(II)-BSPAP.PO(4) at pH 5.0 are similar to those previously reported for Fe(III)Fe(II)-Uf.PO(4) and Fe(III)Zn(II)-Uf.PO(4) complexes at pH 5.0. At higher pH, a new Fe(III)Fe(II)-BSPAP.PO(4) species is formed, with apparent g-values of 1.94, 1.71, and 1.50. The EPR spectrum of Fe(III)Zn(II)-BSPAP does not show significant changes upon addition of phosphate up to 30 mM at pH 6.5, suggesting that phosphate binds only to the spectroscopically silent Zn(II). To determine whether the phosphate complexes were good structural models for the enzyme substrate complexes, these complexes were studied using rapid-freeze EPR and stopped-flow optical spectroscopy. The stopped-flow studies showed the absence of burst kinetics at pH 7.0, which indicates that substrate hydrolysis is rate limiting, rather than phosphate release. The EPR spectrum of Fe(III)Fe(II)-BSPAP.p-NPP is similar, but not identical, to that of the corresponding phosphate complex, both at pH 5 and pH 6.5. We propose that both phosphate and p-NPP bridge the two metal ions at low pH. At higher pH where the enzyme is optimally active, we propose that hydroxide competes with phosphate and p-NPP for coordination to Fe(III) and that both phosphate and p-NPP coordinate only to the divalent metal ion.
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Affiliation(s)
- M Merkx
- E.C. Slater Institute, Biocentrum Amsterdam, University of Amsterdam, The Netherlands
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10
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Merkx M, Averill BA. The activity of oxidized bovine spleen purple acid phosphatase is due to an Fe(III)Zn(II) 'impurity'. Biochemistry 1998; 37:11223-31. [PMID: 9698368 DOI: 10.1021/bi980389r] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Bovine spleen purple acid phosphatase (BSPAP) is a dinuclear iron protein with two stable redox states. The Fe3+Fe2+ state is the active state, while the fully oxidized protein (BSPAPox) has been reported to retain 5-10% activity, corresponding to a kcat of ca. 150 s-1 [Dietrich, M., Münstermann, D., Suerbaum, H., and Witzel, H. (1991) Eur. J. Biochem. 199, 105-113]. Here we show that this activity does not originate from Fe3+Fe3+-BSPAP, but rather from an 'impurity' of FeZn-BSPAP. The FeZn form of BSPAP was prepared from apo-BSPAP following a new procedure, and its kinetic properties were carefully determined for comparison to those of BSPAPox. For the hydrolysis of p-NPP at pH 6.00, both kcat and KM were affected by the Fe2+-to-Zn2+-substitution [Fe3+Fe2+-BSPAP, kcat = (1.8 +/- 0.1) x 10(3) s-1 and KM = 1.2 +/- 0.2 mM; Fe3+Zn2+-BSPAP; kcat = (2.8 +/- 0.2) x 10(3) s-1 and KM = 3.3 +/- 0.4 mM]. The KM of BSPAPox was the same as that of FeZn-BSPAP. pH profiles of BSPAPox and FeZn-BSPAP were both shifted to lower pH compared to that of BSPAPred. FeZn-BSPAP, FeZn-BSPAP.PO4, and FeZn-BSPAP.MoO4 all showed characteristic EPR spectra similar to the corresponding complexes of FeZn-Uf. The same species could also be observed in concentrated samples of native BSPAP. Spin integration of these spectra showed a quantitative relation between the spin concentration of the FeZn-BSPAP 'impurity' and the residual phosphatase activity after oxidation. Since all activity found after oxidation of BSPAP could be attributed to FeZn-BSPAP, there is no direct evidence that Fe3+Fe3+-BSPAP is catalytically active. These results set an upper limit to the possible catalytic activity of the Fe3+Fe3+ form of </=1% of that of the Fe3+Fe2+ form, a finding that is important for understanding the fundamental chemistry by which these dinuclear enzymes catalyze the hydrolysis of phosphate esters.
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Affiliation(s)
- M Merkx
- E.C. Slater Institute, Biocentrum Amsterdam, University of Amsterdam, The Netherlands
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11
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Christianson DW. Structural chemistry and biology of manganese metalloenzymes. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 1998; 67:217-52. [PMID: 9446936 DOI: 10.1016/s0079-6107(97)88477-5] [Citation(s) in RCA: 142] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- D W Christianson
- Department of Chemistry, University of Pennsylvania 19104-6323, USA
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12
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Yang YS, McCormick JM, Solomon EI. Circular Dichroism and Magnetic Circular Dichroism Studies of the Mixed-Valence Binuclear Non-Heme Iron Active Site in Uteroferrin and Its Anion Complexes. J Am Chem Soc 1997. [DOI: 10.1021/ja971896j] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yi-Shan Yang
- Contribution from the Department of Chemistry, Stanford University, Stanford, California 94305
| | - James M. McCormick
- Contribution from the Department of Chemistry, Stanford University, Stanford, California 94305
| | - Edward I. Solomon
- Contribution from the Department of Chemistry, Stanford University, Stanford, California 94305
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13
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14
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Ansai T, Dupuy LC, Barik S. Interactions between a minimal protein serine/threonine phosphatase and its phosphopeptide substrate sequence. J Biol Chem 1996; 271:24401-7. [PMID: 8798696 DOI: 10.1074/jbc.271.40.24401] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The protein phosphatase encoded by coliphage lambda (PPlambda) was found to be the equivalent of the minimal catalytic core of serine/threonine protein phosphatases (PP) by biochemical and mutational criteria. Bacterially expressed truncated versions of PP1 and PP5 phosphatases, representing the catalytic cores homologous to PPlambda, exhibited potent phosphatase activity. Unlike full-length PP1, but like PPlambda, the recombinant cores could use casein, p-nitrophenyl phosphate, and a wide variety of peptides as substrates and were resistant to okadaic acid, microcystin-LR, and trypsin. Mutations of His173, Asp208, or Arg221 had little effect on the activity of the PP1 core protein, indicating its closer identity with PPlambda than with full-length PP1. Terminal deletions of a few amino acids of the cores destroyed their activity, supporting their minimal nature. Analysis of PPlambda mutants suggested an influence of the substrate on metal ion binding. The minimal length of a phosphopeptide substrate of PPlambda appeared to be a phosphorylated serine/threonine flanked by 1 or 2 amino acid residues on either side, the N-terminal ones being more effective.
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Affiliation(s)
- T Ansai
- Department of Biochemistry and Molecular Biology, MSB2140, University of South Alabama College of Medicine, Mobile, Alabama 36688-0002, USA
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15
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Intrinsic Properties of Zinc(II) Ion Pertinent To Zinc Enzymes. ADVANCES IN INORGANIC CHEMISTRY 1996. [DOI: 10.1016/s0898-8838(08)60132-4] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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16
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Goldberg J, Huang HB, Kwon YG, Greengard P, Nairn AC, Kuriyan J. Three-dimensional structure of the catalytic subunit of protein serine/threonine phosphatase-1. Nature 1995; 376:745-53. [PMID: 7651533 DOI: 10.1038/376745a0] [Citation(s) in RCA: 627] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The crystal structure of mammalian protein phosphatase-1, complexed with the toxin microcystin and determined at 2.1 A resolution, reveals that it is a metalloenzyme unrelated in architecture to the tyrosine phosphatases. Two metal ions are positioned by a central beta-alpha-beta-alpha-beta scaffold at the active site, from which emanate three surface grooves that are potential binding sites for substrates and inhibitors. The carboxy terminus is positioned at the end of one of the grooves such that regulatory sequences following the domain might modulate function. The fold of the catalytic domain is expected to be closely preserved in protein phosphatases 2A and 2B (calcineurin).
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Affiliation(s)
- J Goldberg
- Howard Hughes Medical Institute, Rockefeller University, New York, New York 10021, USA
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17
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Barton GJ, Cohen PT, Barford D. Conservation analysis and structure prediction of the protein serine/threonine phosphatases. Sequence similarity with diadenosine tetraphosphatase from Escherichia coli suggests homology to the protein phosphatases. EUROPEAN JOURNAL OF BIOCHEMISTRY 1994; 220:225-37. [PMID: 8119291 DOI: 10.1111/j.1432-1033.1994.tb18618.x] [Citation(s) in RCA: 145] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A multiple sequence alignment of 44 serine/threonine-specific protein phosphatases has been performed. This reveals the position of a common conserved catalytic core, the location of invariant residues, insertions and deletions. The multiple alignment has been used to guide and improve a consensus secondary-structure prediction for the common catalytic core. The location of insertions and deletions has aided in defining the positions of surface loops and turns. The prediction suggests that the core protein phosphatase structure comprises two domains: the first has a single, beta sheet flanked by alpha helices, while the second is predominantly alpha helical. Knowledge of the core secondary structures provides a guide for the design of site-directed-mutagenesis experiments that will not disrupt the native phosphatase fold. A sequence similarity between eukaryotic serine/threonine protein phosphatases and the Escherichia coli diadenosine tetraphosphatase has been identified. This extends over the N-terminal 100 residues of bacteriophage phosphatases and E. coli diadenosine tetraphosphatase. Residues which are invariant amongst these classes are likely to be important in catalysis and protein folding. These include Arg92, Asn138, Asp59, Asp88, Gly58, Gly62, Gly87, Gly93, Gly137, His61, His139 and Val90 and fall into three clusters with the consensus sequences GD(IVTL)HG, GD(LYF)V(DA)RG and GNH, where brackets surround alternative amino acids. The first two consensus sequences are predicted to fall in the beta-alpha and beta-beta loops of a beta-alpha-beta-beta secondary-structure motif. This places the predicted phosphate-binding site at the N-terminus of the alpha helix, where phosphate binding may be stabilised by the alpha-helix dipole.
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Affiliation(s)
- G J Barton
- Laboratory of Molecular Biophysics, University of Oxford, England
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18
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Zhang Z, Zhao S, Deans-Zirattu S, Bai G, Lee EY. Mutagenesis of the catalytic subunit of rabbit muscle protein phosphatase-1. Mol Cell Biochem 1993; 127-128:113-9. [PMID: 7935343 DOI: 10.1007/bf01076762] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We have generated site-directed mutants of the catalytic subunit of rabbit muscle ppase-1. Since it is known that ppase-1 and ppase-2A are highly susceptible to inactivation by sulfhydryl reagents, we have mutagenized the six cysteine residues conserved between these two enzymes to serines. The six mutants were purified to near homogeneity by affinity chromatography on inhibitor-2-Sepharose and characterized. All six exhibited enzymatic activity. These results indicate that the catalytic mechanism of ppase-1 is different from that of the protein tyrosine phosphatases which involve a cysteinyl phosphate intermediate.
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Affiliation(s)
- Z Zhang
- Department of Biochemistry & Molecular Biology, University of Miami School of Medicine, FL 33101
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19
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Orlando JL, Zirino T, Quirk BJ, Averill BA. Purification and properties of the native form of the purple acid phosphatase from bovine spleen. Biochemistry 1993; 32:8120-9. [PMID: 8394126 DOI: 10.1021/bi00083a010] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The purple acid phosphatase (PAP) from bovine spleen has been shown to exist as a single ca. 36-kDa polypeptide in intact spleen tissue. The previously isolated microheterogeneous complex of 15-kDa and 23- or 21-kDa subunits appears to arise from proteolytic cleavage of an exposed, highly variable loop in the polypeptide chain. Small amounts of a single polypeptide form, presumed to be the native form of the enzyme, have been obtained; this has permitted its optical and EPR spectra and fundamental kinetic properties to be determined. The most notable difference between the native and two-subunit forms of PAP is a ca. 3-fold higher enzymatic activity for the latter, which is due to a simple increase in Vmax. The two forms are very similar spectroscopically and chemically and appear to differ only in the loss of a highly antigenic ca. five amino acid segment of the polypeptide between positions 155 and 160 but not in NH2-terminal sequence or in carbohydrate content. Analysis of published sequence data suggests that the existence of an exposed highly antigenic loop at positions corresponding to 155-161 of the spleen PAP sequence is a relatively general feature of PAP's. Trypsin and chymotrypsin cleave both bovine spleen PAP and uteroferrin, apparently in this region, with significant enhancement of enzymatic activity.
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Affiliation(s)
- J L Orlando
- Department of Chemistry, University of Virginia, Charlottesville 22901
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20
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Wang Z, Ming LJ, Que L, Vincent JB, Crowder MW, Averill BA. 1H NMR and NOE studies of the purple acid phosphatases from porcine uterus and bovine spleen. Biochemistry 1992; 31:5263-8. [PMID: 1606150 DOI: 10.1021/bi00138a004] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The diiron active sites of the purple acid phosphatases from porcine uterus (also called uteroferrin, Uf) and bovine spleen (BSPAP) and their complexes with tungstate are compared by 1H NMR and NOE techniques. The paramagnetically shifted features of the 1H NMR spectrum of reduced BSPAP are similar to those of reduced Uf, while the spectra of the tungstate complexes are almost identical. These observations suggest that the two active sites are quite similar, in agreement with the greater than 90% sequence homology found in the two enzymes. Nuclear Overhauser effect (NOE) experiments on the His N-H resonances show that the Fe(III)-His residue is N epsilon-coordinated, while the Fe(II)-His is H delta-coordinated in both enzymes. On the basis of the above NMR and NOE results, our previously proposed model for the dinuclear iron active site of Uf [Scarrow, R. C., Pyrz, J. W., & Que, L., Jr. (1990) J. Am. Chem. Soc. 112, 657-665] is corroborated, refined, and found to represent the diiron center of BSPAP as well.
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Affiliation(s)
- Z Wang
- Department of Chemistry, University of Minnesota, Minneapolis 55455
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Vincent JB, Crowder MW, Averill BA. Hydrolysis of phosphate monoesters: a biological problem with multiple chemical solutions. Trends Biochem Sci 1992; 17:105-10. [PMID: 1412693 DOI: 10.1016/0968-0004(92)90246-6] [Citation(s) in RCA: 194] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Formation of phosphate esters by kinases has long been recognized as an important process in biochemistry, but the reverse reaction, hydrolysis of phosphate esters by phosphatases, has attracted less attention. Recent work suggests that phosphatases are as important as kinases in regulatory processes, and that they constitute a diverse group of enzymes that utilize a variety of chemical means to accelerate phosphate ester hydrolysis.
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Affiliation(s)
- J B Vincent
- Department of Chemistry, University of Alabama, Tuscaloosa 35487
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Wo YY, Zhou MM, Stevis P, Davis JP, Zhang ZY, Van Etten RL. Cloning, expression, and catalytic mechanism of the low molecular weight phosphotyrosyl protein phosphatase from bovine heart. Biochemistry 1992; 31:1712-21. [PMID: 1339287 DOI: 10.1021/bi00121a019] [Citation(s) in RCA: 87] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The first representative of a group of mammalian, low molecular weight phosphotyrosyl protein phosphatases was cloned, sequenced and expressed in Escherichia coli. Using a 61-mer oligonucleotide probe based on the amino acid sequence of the purified enzyme, several overlapping cDNA clones were isolated from a bovine heart cDNA library. A full-length clone was obtained consisting of a 27-bp 5' noncoding region, an open reading frame encoding the expected 157 amino acid protein, and an extensive 3' nontranslated sequence. The identification of the clone as full length was consistent with results obtained in mRNA blotting experiments using poly(A)+ mRNA from bovine heart. The coding sequence was placed downstream of a bacteriophage T7 promoter, and protein was expressed in E. coli. The expressed enzyme was soluble, and catalytically active and was readily isolated and purified. The recombinant protein had the expected Mr of 18,000 (estimated by SDS-PAGE), and it showed cross-reactivity with antisera that had been raised against both the bovine heart and the human placenta enzymes. The amino acid sequence of the N-terminal region of the expressed protein showed that methionine had been removed, resulting in a sequence identical to that of the enzyme isolated from the bovine tissue, with the exception that the N-terminal alanine of the protein from tissue is acetylated. A kinetically competent phosphoenzyme intermediate was trapped from a phosphatase-catalyzed reaction. Using 31P NMR, the covalent intermediate was identified as a cysteinyl phosphate. By analogy with the nomenclature used for serine esterases, these enzymes may be called cysteine phosphatases.
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Affiliation(s)
- Y Y Wo
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-1393
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