1
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Breeze CW, Nakano Y, Campbell EC, Frkic RL, Lupton DW, Jackson CJ. Mononuclear binding and catalytic activity of europium(III) and gadolinium(III) at the active site of the model metalloenzyme phosphotriesterase. Acta Crystallogr D Struct Biol 2024; 80:289-298. [PMID: 38512071 PMCID: PMC10994177 DOI: 10.1107/s2059798324002316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Accepted: 03/10/2024] [Indexed: 03/22/2024] Open
Abstract
Lanthanide ions have ideal chemical properties for catalysis, such as hard Lewis acidity, fast ligand-exchange kinetics, high coordination-number preferences and low geometric requirements for coordination. As a result, many small-molecule lanthanide catalysts have been described in the literature. Yet, despite the ability of enzymes to catalyse highly stereoselective reactions under gentle conditions, very few lanthanoenzymes have been investigated. In this work, the mononuclear binding of europium(III) and gadolinium(III) to the active site of a mutant of the model enzyme phosphotriesterase are described using X-ray crystallography at 1.78 and 1.61 Å resolution, respectively. It is also shown that despite coordinating a single non-natural metal cation, the PTE-R18 mutant is still able to maintain esterase activity.
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Affiliation(s)
- Callum W. Breeze
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Yuji Nakano
- School of Chemistry, Monash University, Clayton, Melbourne, VIC 3800, Australia
| | - Eleanor C. Campbell
- Australian Synchrotron, 800 Blackburn Road, Clayton, Melbourne, VIC 3168, Australia
| | - Rebecca L. Frkic
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - David W. Lupton
- School of Chemistry, Monash University, Clayton, Melbourne, VIC 3800, Australia
| | - Colin J. Jackson
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
- Australian Research Council Centre of Excellence in Synthetic Biology, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
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2
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Dym O, Aggarwal N, Ashani Y, Leader H, Albeck S, Unger T, Hamer-Rogotner S, Silman I, Tawfik DS, Sussman JL. The impact of molecular variants, crystallization conditions and the space group on ligand-protein complexes: a case study on bacterial phosphotriesterase. Acta Crystallogr D Struct Biol 2023; 79:992-1009. [PMID: 37860961 PMCID: PMC10619419 DOI: 10.1107/s2059798323007672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 09/03/2023] [Indexed: 10/21/2023] Open
Abstract
A bacterial phosphotriesterase was employed as an experimental paradigm to examine the effects of multiple factors, such as the molecular constructs, the ligands used during protein expression and purification, the crystallization conditions and the space group, on the visualization of molecular complexes of ligands with a target enzyme. In this case, the ligands used were organophosphates that are fragments of the nerve agents and insecticides on which the enzyme acts as a bioscavenger. 12 crystal structures of various phosphotriesterase constructs obtained by directed evolution were analyzed, with resolutions of up to 1.38 Å. Both apo forms and holo forms, complexed with the organophosphate ligands, were studied. Crystals obtained from three different crystallization conditions, crystallized in four space groups, with and without N-terminal tags, were utilized to investigate the impact of these factors on visualizing the organophosphate complexes of the enzyme. The study revealed that the tags used for protein expression can lodge in the active site and hinder ligand binding. Furthermore, the space group in which the protein crystallizes can significantly impact the visualization of bound ligands. It was also observed that the crystallization precipitants can compete with, and even preclude, ligand binding, leading to false positives or to the incorrect identification of lead drug candidates. One of the co-crystallization conditions enabled the definition of the spaces that accommodate the substituents attached to the P atom of several products of organophosphate substrates after detachment of the leaving group. The crystal structures of the complexes of phosphotriesterase with the organophosphate products reveal similar short interaction distances of the two partially charged O atoms of the P-O bonds with the exposed β-Zn2+ ion and the buried α-Zn2+ ion. This suggests that both Zn2+ ions have a role in stabilizing the transition state for substrate hydrolysis. Overall, this study provides valuable insights into the challenges and considerations involved in studying the crystal structures of ligand-protein complexes, highlighting the importance of careful experimental design and rigorous data analysis in ensuring the accuracy and reliability of the resulting phosphotriesterase-organophosphate structures.
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Affiliation(s)
- Orly Dym
- Department of Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot, Israel
| | - Nidhi Aggarwal
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Yacov Ashani
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Haim Leader
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Shira Albeck
- Department of Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot, Israel
| | - Tamar Unger
- Department of Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot, Israel
| | - Shelly Hamer-Rogotner
- Department of Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot, Israel
| | - Israel Silman
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Dan S. Tawfik
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Joel L. Sussman
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot, Israel
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3
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Marone M, Porzio E, Lampitella EA, Manco G. A mesophilic phosphotriesterase-like lactonase shows high stability and proficiency as quorum quenching enzyme. Chem Biol Interact 2023; 383:110657. [PMID: 37573927 DOI: 10.1016/j.cbi.2023.110657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 08/04/2023] [Accepted: 08/09/2023] [Indexed: 08/15/2023]
Abstract
The problem of biofilm formation is a serious concern under various pathological conditions such as extensive burns, wounds in diabetic patients, bedsores, cystic fibrosis, nosocomial infections from implantable medical devices such as catheters, valves, etc. Environmental diffusion of biofilm (in pools, wet floors, industrial food plants) that could represent a reservoir of antibiotic resistant bacteria constitues an additional issue. In this work is described a lactonase from Rhodococcus erythropolis, a phosphotriesterase-like lactonase (PLL) enzyme, which has already been studied in the past and can be used for containment of biofilm formation. The protein is 28% and 40% identical with respect to the Pseudomonas diminuta PTE and the thermostable Saccharolobus solfataricus SsoPox respectively. The protein was obtained starting from a synthetic His-tagged gene, expressed in E. coli, purified and further characterized. New properties, not previously known or deducible from its sequence, have been highlighted. These properties are: the enzyme is thermophilic and thermostable even though it originates from a mesophilic bacterium; the enzyme has a long (months) shelf life at 4 °C; the enzyme is not only stable to low concentrations of the oxidant H2O2 but even activated by it at high concentrations; the enzyme proved to be a proficient quorum quenching enzyme, able to hydrolase acyl-homoserine lactones 3oxoC12-HSL and C4-HSL, and can inhibit up to 60% the formation of Pseudomonas aeruginosa (PAO1) biofilm. These different properties make the lactonase useful to fight resistant bacteria that induce inflammatory and infectious processes mediated by the quorum sensing mechanism.
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Affiliation(s)
- Maria Marone
- Institute of Biochemistry and Cell Biology. National Research Council of Italy, Via P. Castellino 111, Naples, Italy
| | - Elena Porzio
- Institute of Biochemistry and Cell Biology. National Research Council of Italy, Via P. Castellino 111, Naples, Italy
| | - Eros Antonio Lampitella
- Institute of Biochemistry and Cell Biology. National Research Council of Italy, Via P. Castellino 111, Naples, Italy
| | - Giuseppe Manco
- Institute of Biochemistry and Cell Biology. National Research Council of Italy, Via P. Castellino 111, Naples, Italy.
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4
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Yu J, Fu Y, Cao Z. QM/MM and MM MD Simulations on Enzymatic Degradation of the Nerve Agent VR by Phosphotriesterase. J Phys Chem B 2023; 127:7462-7471. [PMID: 37584503 DOI: 10.1021/acs.jpcb.3c03952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/17/2023]
Abstract
V-type nerve agents are hardly degraded by phosphotriesterase (PTE). Interestingly, the PTE variant of BHR-73MNW can effectively improve the hydrolytic efficiency of VR, especially for its Sp-enantiomer. Here, the whole enzymatic degradation of both Sp and Rp enantiomers of VR by the wild-type PTE and its variant BHR-73MNW was investigated by quantum mechanics/molecular mechanics (QM/MM) calculations and MM molecular dynamics simulations. Present results indicate that the degradation of VR can be initiated by the nucleophilic attack of the bridging OH- and the zinc-bound water molecule. The QM/MM-predicted energy barriers for the hydrolytic process of Sp-VR are 19.8 kcal mol-1 by the variant with water as a nucleophile and 22.0 kcal mol-1 by the wild-type PTE with OH- as a nucleophile, and corresponding degraded products are bound to the dinuclear metal site in monodentate and bidentate coordination modes, respectively. The variant effectively increases the volume of the large pocket, allowing more water molecules to enter the active pocket and resulting in the improvement of the degradation efficiency of Sp-VR. The hydrolysis of Rp-VR is triggered only by the hydroxide with an energy span of 20.6 kcal mol-1 for the wild-type PTE and 20.7 kcal mol-1 for the variant BHR-73-MNW PTE. Such mechanistic insights into the stereoselective degradation of VR by PTE and the role of water may inspire further studies to improve the catalytic efficiency of PTE toward the detoxification of nerve agents.
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Affiliation(s)
- Jun Yu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Yuzhuang Fu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Zexing Cao
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
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5
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Job L, Köhler A, Testanera M, Escher B, Worek F, Skerra A. Engineering of a phosphotriesterase with improved stability and enhanced activity for detoxification of the pesticide metabolite malaoxon. Protein Eng Des Sel 2023; 36:gzad020. [PMID: 37941439 DOI: 10.1093/protein/gzad020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 10/30/2023] [Accepted: 11/03/2023] [Indexed: 11/10/2023] Open
Abstract
Organophosphorus (OP) pesticides are still widely applied but pose a severe toxicological threat if misused. For in vivo detoxification, the application of hydrolytic enzymes potentially offers a promising treatment. A well-studied example is the phosphotriesterase of Brevundimonas diminuta (BdPTE). Whereas wild-type BdPTE can hydrolyse pesticides like paraoxon, chlorpyrifos-oxon and mevinphos with high catalytic efficiencies, kcat/KM >2 × 107 M-1 min-1, degradation of malaoxon is unsatisfactory (kcat/KM ≈ 1 × 104 M-1 min-1). Here, we report the rational engineering of BdPTE mutants with improved properties and their efficient production in Escherichia coli. As result, the mutant BdPTE(VRNVVLARY) exhibits 37-fold faster malaoxon hydrolysis (kcat/KM = 4.6 × 105 M-1 min-1), together with enhanced expression yield, improved thermal stability and reduced susceptibility to oxidation. Therefore, this BdPTE mutant constitutes a powerful candidate to develop a biocatalytic antidote for the detoxification of this common pesticide metabolite as well as related OP compounds.
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Affiliation(s)
- Laura Job
- Lehrstuhl für Biologische Chemie, Technische Universität München, Emil-Erlenmeyer-Forum 5, 85354 Freising, Germany
| | - Anja Köhler
- Lehrstuhl für Biologische Chemie, Technische Universität München, Emil-Erlenmeyer-Forum 5, 85354 Freising, Germany
- Institut für Pharmakologie und Toxikologie der Bundeswehr, Neuherbergstr, 11, 80937 München, Germany
| | - Mauricio Testanera
- Lehrstuhl für Biologische Chemie, Technische Universität München, Emil-Erlenmeyer-Forum 5, 85354 Freising, Germany
| | - Benjamin Escher
- Lehrstuhl für Biologische Chemie, Technische Universität München, Emil-Erlenmeyer-Forum 5, 85354 Freising, Germany
| | - Franz Worek
- Institut für Pharmakologie und Toxikologie der Bundeswehr, Neuherbergstr, 11, 80937 München, Germany
| | - Arne Skerra
- Lehrstuhl für Biologische Chemie, Technische Universität München, Emil-Erlenmeyer-Forum 5, 85354 Freising, Germany
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6
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Day GJ, Zhang WH, Carter BM, Xiao W, Sambrook MR, Perriman AW. A Rationally Designed Supercharged Protein-Enzyme Chimera Self-Assembles In Situ to Yield Bifunctional Composite Textiles. ACS Appl Mater Interfaces 2021; 13:60433-60445. [PMID: 34894651 DOI: 10.1021/acsami.1c18857] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Catalytically active materials for the enhancement of personalized protective equipment (PPE) could be advantageous to help alleviate threats posed by neurotoxic organophosphorus compounds (OPs). Accordingly, a chimeric protein comprised of a supercharged green fluorescent protein (scGFP) and phosphotriesterase from Agrobacterium radiobacter (arPTE) was designed to drive the polymer surfactant (S-)-mediated self-assembly of microclusters to produce robust, enzymatically active materials. The chimera scGFP-arPTE was structurally characterized via circular dichroism spectroscopy and synchrotron radiation small-angle X-ray scattering, and its biophysical properties were determined. Significantly, the chimera exhibited greater thermal stability than the native constituent proteins, as well as a higher catalytic turnover number (kcat). Furthermore, scGFP-arPTE was electrostatically complexed with monomeric S-, driving self-assembly into [scGFP-arPTE][S-] nanoclusters, which could be dehydrated and cross-linked to yield enzymatically active [scGFP-arPTE][S-] porous films with a high-order structure. Moreover, these clusters could self-assemble within cotton fibers to generate active composite textiles without the need for the pretreatment of the fabrics. Significantly, the resulting materials maintained the biophysical activities of both constituent proteins and displayed recyclable and persistent activity against the nerve agent simulant paraoxon.
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Affiliation(s)
- Graham J Day
- School of Cellular and Molecular Medicine, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom
| | - William H Zhang
- School of Cellular and Molecular Medicine, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom
| | - Ben M Carter
- School of Cellular and Molecular Medicine, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom
| | - Wenjin Xiao
- School of Cellular and Molecular Medicine, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom
| | - Mark R Sambrook
- CBR Division, Defence Science and Technology Laboratory (Dstl), Porton Down, Salisbury SP4 0JQ, United Kingdom
| | - Adam W Perriman
- School of Cellular and Molecular Medicine, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom
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7
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Zlobin A, Diankin I, Pushkarev S, Golovin A. Probing the Suitability of Different Ca 2+ Parameters for Long Simulations of Diisopropyl Fluorophosphatase. Molecules 2021; 26:5839. [PMID: 34641383 PMCID: PMC8510429 DOI: 10.3390/molecules26195839] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 09/23/2021] [Accepted: 09/24/2021] [Indexed: 11/16/2022] Open
Abstract
Organophosphate hydrolases are promising as potential biotherapeutic agents to treat poisoning with pesticides or nerve gases. However, these enzymes often need to be further engineered in order to become useful in practice. One example of such enhancement is the alteration of enantioselectivity of diisopropyl fluorophosphatase (DFPase). Molecular modeling techniques offer a unique opportunity to address this task rationally by providing a physical description of the substrate-binding process. However, DFPase is a metalloenzyme, and correct modeling of metal cations is a challenging task generally coming with a tradeoff between simulation speed and accuracy. Here, we probe several molecular mechanical parameter combinations for their ability to empower long simulations needed to achieve a quantitative description of substrate binding. We demonstrate that a combination of the Amber19sb force field with the recently developed 12-6 Ca2+ models allows us to both correctly model DFPase and obtain new insights into the DFP binding process.
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Affiliation(s)
- Alexander Zlobin
- Faculty of Bioengineering, Lomonosov Moscow State University, 119234 Moscow, Russia; (I.D.); (S.P.)
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Sirius University of Science and Technology, 354340 Sochi, Russia
| | - Igor Diankin
- Faculty of Bioengineering, Lomonosov Moscow State University, 119234 Moscow, Russia; (I.D.); (S.P.)
- Sirius University of Science and Technology, 354340 Sochi, Russia
| | - Sergey Pushkarev
- Faculty of Bioengineering, Lomonosov Moscow State University, 119234 Moscow, Russia; (I.D.); (S.P.)
| | - Andrey Golovin
- Faculty of Bioengineering, Lomonosov Moscow State University, 119234 Moscow, Russia; (I.D.); (S.P.)
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Sirius University of Science and Technology, 354340 Sochi, Russia
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8
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Köhler A, Escher B, Job L, Koller M, Thiermann H, Skerra A, Worek F. Catalytic activity and stereoselectivity of engineered phosphotriesterases towards structurally different nerve agents in vitro. Arch Toxicol 2021; 95:2815-2823. [PMID: 34160649 PMCID: PMC8298220 DOI: 10.1007/s00204-021-03094-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 06/15/2021] [Indexed: 12/20/2022]
Abstract
Highly toxic organophosphorus nerve agents, especially the extremely stable and persistent V-type agents such as VX, still pose a threat to the human population and require effective medical countermeasures. Engineered mutants of the Brevundimonas diminuta phosphotriesterase (BdPTE) exhibit enhanced catalytic activities and have demonstrated detoxification in animal models, however, substrate specificity and fast plasma clearance limit their medical applicability. To allow better assessment of their substrate profiles, we have thoroughly investigated the catalytic efficacies of five BdPTE mutants with 17 different nerve agents using an AChE inhibition assay. In addition, we studied one BdPTE version that was fused with structurally disordered PAS polypeptides to enable delayed plasma clearance and one bispecific BdPTE with broadened substrate spectrum composed of two functionally distinct subunits connected by a PAS linker. Measured kcat/KM values were as high as 6.5 and 1.5 × 108 M-1 min-1 with G- and V-agents, respectively. Furthermore, the stereoselective degradation of VX enantiomers by the PASylated BdPTE-4 and the bispecific BdPTE-7 were investigated by chiral LC-MS/MS, resulting in a several fold faster hydrolysis of the more toxic P(-) VX stereoisomer compared to P(+) VX. In conclusion, the newly developed enzymes BdPTE-4 and BdPTE-7 have shown high catalytic efficacy towards structurally different nerve agents and stereoselectivity towards the toxic P(-) VX enantiomer in vitro and offer promise for use as bioscavengers in vivo.
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Affiliation(s)
- Anja Köhler
- Institut für Pharmakologie und Toxikologie der Bundeswehr, 80937, Munich, Germany
- Lehrstuhl für Biologische Chemie, Technische Universität München, 85354, Freising, Germany
| | - Benjamin Escher
- Lehrstuhl für Biologische Chemie, Technische Universität München, 85354, Freising, Germany
| | - Laura Job
- Lehrstuhl für Biologische Chemie, Technische Universität München, 85354, Freising, Germany
| | - Marianne Koller
- Institut für Pharmakologie und Toxikologie der Bundeswehr, 80937, Munich, Germany
| | - Horst Thiermann
- Institut für Pharmakologie und Toxikologie der Bundeswehr, 80937, Munich, Germany
| | - Arne Skerra
- Lehrstuhl für Biologische Chemie, Technische Universität München, 85354, Freising, Germany.
| | - Franz Worek
- Institut für Pharmakologie und Toxikologie der Bundeswehr, 80937, Munich, Germany.
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9
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Emond S, Petek M, Kay EJ, Heames B, Devenish SRA, Tokuriki N, Hollfelder F. Accessing unexplored regions of sequence space in directed enzyme evolution via insertion/deletion mutagenesis. Nat Commun 2020; 11:3469. [PMID: 32651386 PMCID: PMC7351745 DOI: 10.1038/s41467-020-17061-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 06/01/2020] [Indexed: 11/22/2022] Open
Abstract
Insertions and deletions (InDels) are frequently observed in natural protein evolution, yet their potential remains untapped in laboratory evolution. Here we introduce a transposon-based mutagenesis approach (TRIAD) to generate libraries of random variants with short in-frame InDels, and screen TRIAD libraries to evolve a promiscuous arylesterase activity in a phosphotriesterase. The evolution exhibits features that differ from previous point mutagenesis campaigns: while the average activity of TRIAD variants is more compromised, a larger proportion has successfully adapted for the activity. Different functional profiles emerge: (i) both strong and weak trade-off between activities are observed; (ii) trade-off is more severe (20- to 35-fold increased kcat/KM in arylesterase with 60-400-fold decreases in phosphotriesterase activity) and (iii) improvements are present in kcat rather than just in KM, suggesting adaptive solutions. These distinct features make TRIAD an alternative to widely used point mutagenesis, accessing functional innovations and traversing unexplored fitness landscape regions.
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Affiliation(s)
- Stephane Emond
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK.
- Evonetix Ltd, Coldhams Business Park, Norman Way, Cambridge, CB1 3LH, UK.
| | - Maya Petek
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK
| | - Emily J Kay
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK
- Cancer Research UK Beatson Institute, Glasgow, G61 1BD, UK
| | - Brennen Heames
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK
- Institute for Evolution and Biodiversity, Westfälische Wilhelms-Universität, Hüfferstrasse 1, 48149, Münster, Germany
| | - Sean R A Devenish
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK
- Fluidic Analytics, The Paddocks Business Centre, Cherry Hinton Road, Cambridge, CB1 8DH, UK
| | - Nobuhiko Tokuriki
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Florian Hollfelder
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK.
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10
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Despotović D, Aharon E, Dubovetskyi A, Leader H, Ashani Y, Tawfik DS. A mixture of three engineered phosphotriesterases enables rapid detoxification of the entire spectrum of known threat nerve agents. Protein Eng Des Sel 2020; 32:169-174. [PMID: 31612205 DOI: 10.1093/protein/gzz039] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 08/27/2019] [Accepted: 08/28/2019] [Indexed: 01/22/2023] Open
Abstract
Nerve agents are organophosphates (OPs) that potently inhibit acetylcholinesterase, and their enzymatic detoxification has been a long-standing goal. Nerve agents vary widely in size, charge, hydrophobicity and the cleavable ester bond. A single enzyme is therefore unlikely to efficiently hydrolyze all agents. Here, we describe a mixture of three previously developed variants of the bacterial phosphotriesterase (Bd-PTE) that are highly stable and nearly sequence identical. This mixture enables effective detoxification of a broad spectrum of known threat agents-GA (tabun), GB (sarin), GD (soman), GF (cyclosarin), VX and Russian-VX. The potential for dimer dissociation and exchange that could inactivate Bd-PTE has minimal impact, and the three enzyme variants are as active in a mixture as they are individually. To our knowledge, this engineered enzyme 'cocktail' comprises the first solution for enzymatic detoxification of the entire range of threat nerve agents.
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Affiliation(s)
- Dragana Despotović
- Department of Biomolecular Sciences, Weizmann Institute of Science, Herzl st. 234, Rehovot 7610001, Israel
| | - Einav Aharon
- Department of Biomolecular Sciences, Weizmann Institute of Science, Herzl st. 234, Rehovot 7610001, Israel
| | - Artem Dubovetskyi
- Department of Biomolecular Sciences, Weizmann Institute of Science, Herzl st. 234, Rehovot 7610001, Israel
| | - Haim Leader
- Department of Biomolecular Sciences, Weizmann Institute of Science, Herzl st. 234, Rehovot 7610001, Israel
| | - Yacov Ashani
- Department of Biomolecular Sciences, Weizmann Institute of Science, Herzl st. 234, Rehovot 7610001, Israel
| | - Dan S Tawfik
- Department of Biomolecular Sciences, Weizmann Institute of Science, Herzl st. 234, Rehovot 7610001, Israel
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11
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Zueva IV, Lushchekina SV, Daudé D, Chabrière E, Masson P. Steady-State Kinetics of Enzyme-Catalyzed Hydrolysis of Echothiophate, a P-S Bonded Organophosphorus as Monitored by Spectrofluorimetry. Molecules 2020; 25:molecules25061371. [PMID: 32192230 PMCID: PMC7144395 DOI: 10.3390/molecules25061371] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 03/14/2020] [Accepted: 03/16/2020] [Indexed: 02/02/2023] Open
Abstract
Enzyme-catalyzed hydrolysis of echothiophate, a P–S bonded organophosphorus (OP) model, was spectrofluorimetrically monitored, using Calbiochem Probe IV as the thiol reagent. OP hydrolases were: the G117H mutant of human butyrylcholinesterase capable of hydrolyzing OPs, and a multiple mutant of Brevundimonas diminuta phosphotriesterase, GG1, designed to hydrolyze a large spectrum of OPs at high rate, including V agents. Molecular modeling of interaction between Probe IV and OP hydrolases (G117H butyrylcholinesterase, GG1, wild types of Brevundimonas diminuta and Sulfolobus solfataricus phosphotriesterases, and human paraoxonase-1) was performed. The high sensitivity of the method allowed steady-state kinetic analysis of echothiophate hydrolysis by highly purified G117H butyrylcholinesterase concentration as low as 0.85 nM. Hydrolysis was michaelian with Km = 0.20 ± 0.03 mM and kcat = 5.4 ± 1.6 min−1. The GG1 phosphotriesterase hydrolyzed echothiophate with a high efficiency (Km = 2.6 ± 0.2 mM; kcat = 53400 min−1). With a kcat/Km = (2.6 ± 1.6) × 107 M−1min−1, GG1 fulfills the required condition of potential catalytic bioscavengers. quantum mechanics/molecular mechanics (QM/MM) and molecular docking indicate that Probe IV does not interact significantly with the selected phosphotriesterases. Moreover, results on G117H mutant show that Probe IV does not inhibit butyrylcholinesterase. Therefore, Probe IV can be recommended for monitoring hydrolysis of P–S bonded OPs by thiol-free OP hydrolases.
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Affiliation(s)
- Irina V. Zueva
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center “Kazan Scientific Center of the Russian Academy of Sciences”, Arbuzov str. 8, 420088 Kazan, Russia;
| | - Sofya V. Lushchekina
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Kosygin str 4, 119334 Moscow, Russia;
| | - David Daudé
- Gene&GreenTK, HU Méditerranée Infection, Jean Moulin Blvd 19–21, 13005 Marseille, France;
| | - Eric Chabrière
- Aix-Marseille University, IRD, APHM, MEPHI, IHU-Méditerranée Infection, 15005 Marseille, France;
| | - Patrick Masson
- Kazan Federal University, Neuropharmacology Laboratory, Kremlevskaya str 18, 480002 Kazan, Russia
- Correspondence: ; Tel.: +7-96-5581-0473
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12
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Vitola G, Mazzei R, Poerio T, Porzio E, Manco G, Perrotta I, Militano F, Giorno L. Biocatalytic membrane reactor development for organophosphates degradation. J Hazard Mater 2019; 365:789-795. [PMID: 30476802 DOI: 10.1016/j.jhazmat.2018.11.063] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 11/14/2018] [Accepted: 11/15/2018] [Indexed: 06/09/2023]
Abstract
Organophosphates (OPs) are highly toxic compounds used as pesticides and nerve agents. The devastating effects, reported in different studies, on the environment and human health indicate a serious scenario for both instantaneous and long terms effects. Bio-based strategies for OPs degradation seem the most promising solutions, particularly when extremophiles enzymes are used. These systems permit OPs degradation with high efficiency and specificity under mild conditions. However, as frequently observed, enzymes can easily lose activity in batch systems, so that a strategy to improve biocatalyst stability is highly needed, in order to develop continuous systems. In this work, for the first time, a continuous biocatalytic system for organophosphates (OPs) detoxification has been proposed by using a triple mutant of the thermostable phosphotriesterase (named SsoPox) isolated from the hyperthermophilic archaeon Sulfolobus solfataricus. The enzyme was covalently immobilized on polymeric membranes to develop a biocatalytic membrane reactor (BMR) able to hydrolyse a pesticide (paraoxon) contained in water. High paraoxon degradation (about 90%) and long term stability (1 year) were obtained when the enzyme was covalently immobilized on hydrophilic membranes. On the contrary, the enzyme in batch system completely loses its activity within few months after its solubilisation in buffer.
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Affiliation(s)
- G Vitola
- Institute on Membrane Technology, National Research Council, ITM-CNR, via P. Bucci, 17/C, 87036 Rende, Cosenza, Italy
| | - R Mazzei
- Institute on Membrane Technology, National Research Council, ITM-CNR, via P. Bucci, 17/C, 87036 Rende, Cosenza, Italy.
| | - T Poerio
- Institute on Membrane Technology, National Research Council, ITM-CNR, via P. Bucci, 17/C, 87036 Rende, Cosenza, Italy
| | - E Porzio
- Institute of Protein Biochemistry, National Research Council, IBP-CNR, via P. Castellino 111, 80131 Naples, Italy
| | - G Manco
- Institute of Protein Biochemistry, National Research Council, IBP-CNR, via P. Castellino 111, 80131 Naples, Italy
| | - I Perrotta
- Centre for Microscopy and Microanalysis (CM2), Dept. of Biology, Ecology and Earth Sciences, University of Calabria, 87036 Rende, Cosenza, Italy
| | - F Militano
- Institute on Membrane Technology, National Research Council, ITM-CNR, via P. Bucci, 17/C, 87036 Rende, Cosenza, Italy
| | - L Giorno
- Institute on Membrane Technology, National Research Council, ITM-CNR, via P. Bucci, 17/C, 87036 Rende, Cosenza, Italy
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13
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Siddavattam D, Yakkala H, Samantarrai D. Lateral transfer of organophosphate degradation ( opd) genes among soil bacteria: mode of transfer and contributions to organismal fitness. J Genet 2019; 98:23. [PMID: 30945693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Genes encoding structurally independent phosphotriesterases (PTEs) are identified in soil bacteria. These pte genes, often identified on mobilizable and self-transmissible plasmids are organized as mobile genetic elements. Their dissemination through lateral gene transfer is evident due to the detection of identical organophosphate degradation genes among soil bacteria with little orno taxonomic relationship. Convergent evolution of PTEs provided selective advantages to the bacterial strain as they convert toxic phosphotriesters (PTs) into a source of phosphate. The residues of organophosphate (OP) compounds that accumulate in a soil are proposed to contribute to the evolution of PTEs through substrate-assisted gain-of-function. This review provides comprehensive information on lateral transfer of pte genes and critically examines proposed hypotheses on their evolution in the light of the short half-life of OPs in the environment. The review also proposes alternate factors that have possibly contributed to the evolution and lateral mobility of PTEs by taking into account their biology and analyses of pte genes in genomic and metagenomic databases.
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Affiliation(s)
- Dayananda Siddavattam
- Department of Animal Sciences, School of Life Sciences, University of Hyderabad, Hyderabad 500 046, India. ;
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14
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Soares FV, de Castro AA, Pereira AF, Leal DHS, Mancini DT, Krejcar O, Ramalho TC, da Cunha EFF, Kuca K. Theoretical Studies Applied to the Evaluation of the DFPase Bioremediation Potential against Chemical Warfare Agents Intoxication. Int J Mol Sci 2018; 19:E1257. [PMID: 29690585 PMCID: PMC5979579 DOI: 10.3390/ijms19041257] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 04/16/2018] [Accepted: 04/19/2018] [Indexed: 11/30/2022] Open
Abstract
Organophosphorus compounds (OP) are part of a group of compounds that may be hazardous to health. They are called neurotoxic agents because of their action on the nervous system, inhibiting the acetylcholinesterase (AChE) enzyme and resulting in a cholinergic crisis. Their high toxicity and rapid action lead to irreversible damage to the nervous system, drawing attention to developing new treatment methods. The diisopropyl fluorophosphatase (DFPase) enzyme has been considered as a potent biocatalyst for the hydrolysis of toxic OP and has potential for bioremediation of this kind of intoxication. In order to investigate the degradation process of the nerve agents Tabun, Cyclosarin and Soman through the wild-type DFPase, and taking into account their stereochemistry, theoretical studies were carried out. The intermolecular interaction energy and other parameters obtained from the molecular docking calculations were used to construct a data matrix, which were posteriorly treated by statistical analyzes of chemometrics, using the PCA (Principal Components Analysis) multivariate analysis. The analyzed parameters seem to be quite important for the reaction mechanisms simulation (QM/MM). Our findings showed that the wild-type DFPase enzyme is stereoselective in hydrolysis, showing promising results for the catalytic degradation of the neurotoxic agents under study, with the degradation mechanism performed through two proposed pathways.
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Affiliation(s)
- Flávia V Soares
- Laboratory of Molecular Modeling, Chemistry Department, Federal University of Lavras, 37200-000 Lavras, MG, Brazil.
| | - Alexandre A de Castro
- Laboratory of Molecular Modeling, Chemistry Department, Federal University of Lavras, 37200-000 Lavras, MG, Brazil.
| | - Ander F Pereira
- Laboratory of Molecular Modeling, Chemistry Department, Federal University of Lavras, 37200-000 Lavras, MG, Brazil.
| | - Daniel H S Leal
- Laboratory of Molecular Modeling, Chemistry Department, Federal University of Lavras, 37200-000 Lavras, MG, Brazil.
- Department of Health Sciences, Federal University of Espírito Santo, 29932-540 São Mateus, ES, Brazil.
| | - Daiana T Mancini
- Laboratory of Molecular Modeling, Chemistry Department, Federal University of Lavras, 37200-000 Lavras, MG, Brazil.
| | - Ondrej Krejcar
- Center for Basic and Applied Research, Faculty of Informatics and Management, University Hradec Kralove, 50003 Hradec Kralove, Czech Republic.
| | - Teodorico C Ramalho
- Laboratory of Molecular Modeling, Chemistry Department, Federal University of Lavras, 37200-000 Lavras, MG, Brazil.
- Center for Basic and Applied Research, Faculty of Informatics and Management, University Hradec Kralove, 50003 Hradec Kralove, Czech Republic.
| | - Elaine F F da Cunha
- Laboratory of Molecular Modeling, Chemistry Department, Federal University of Lavras, 37200-000 Lavras, MG, Brazil.
| | - Kamil Kuca
- Center for Basic and Applied Research, Faculty of Informatics and Management, University Hradec Kralove, 50003 Hradec Kralove, Czech Republic.
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15
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Purg M, Elias M, Kamerlin SCL. Similar Active Sites and Mechanisms Do Not Lead to Cross-Promiscuity in Organophosphate Hydrolysis: Implications for Biotherapeutic Engineering. J Am Chem Soc 2017; 139:17533-17546. [PMID: 29113434 PMCID: PMC5724027 DOI: 10.1021/jacs.7b09384] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Indexed: 01/27/2023]
Abstract
Organophosphate hydrolases are proficient catalysts of the breakdown of neurotoxic organophosphates and have great potential as both biotherapeutics for treating acute organophosphate toxicity and as bioremediation agents. However, proficient organophosphatases such as serum paraoxonase 1 (PON1) and the organophosphate-hydrolyzing lactonase SsoPox are unable to hydrolyze bulkyorganophosphates with challenging leaving groups such as diisopropyl fluorophosphate (DFP) or venomous agent X, creating a major challenge for enzyme design. Curiously, despite their mutually exclusive substrate specificities, PON1 and diisopropyl fluorophosphatase (DFPase) have essentially identical active sites and tertiary structures. In the present work, we use empirical valence bond simulations to probe the catalytic mechanism of DFPase as well as temperature, pH, and mutational effects, demonstrating that DFPase and PON1 also likely utilize identical catalytic mechanisms to hydrolyze their respective substrates. However, detailed examination of both static structures and dynamical simulations demonstrates subtle but significant differences in the electrostatic properties and solvent penetration of the two active sites and, most critically, the role of residues that make no direct contact with either substrate in acting as "specificity switches" between the two enzymes. Specifically, we demonstrate that key residues that are structurally and functionally critical for the paraoxonase activity of PON1 prevent it from being able to hydrolyze DFP with its fluoride leaving group. These insights expand our understanding of the drivers of the evolution of divergent substrate specificity in enzymes with identical active sites and guide the future design of organophosphate hydrolases that hydrolyze compounds with challenging leaving groups.
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Affiliation(s)
- Miha Purg
- Science for Life
Laboratory, Department of Cell and Molecular Biology, Uppsala University, BMC Box 596, S-751 24 Uppsala, Sweden
| | - Mikael Elias
- Department of Biochemistry, Molecular Biology and Biophysics &
Biotechnology Institute, University of Minnesota, 1479 Gortner Avenue, St. Paul, Minnesota 55108, United States
| | - Shina Caroline Lynn Kamerlin
- Science for Life
Laboratory, Department of Cell and Molecular Biology, Uppsala University, BMC Box 596, S-751 24 Uppsala, Sweden
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16
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Jacquet P, Hiblot J, Daudé D, Bergonzi C, Gotthard G, Armstrong N, Chabrière E, Elias M. Rational engineering of a native hyperthermostable lactonase into a broad spectrum phosphotriesterase. Sci Rep 2017; 7:16745. [PMID: 29196634 PMCID: PMC5711954 DOI: 10.1038/s41598-017-16841-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 11/16/2017] [Indexed: 11/13/2022] Open
Abstract
The redesign of enzyme active sites to alter their function or specificity is a difficult yet appealing challenge. Here we used a structure-based design approach to engineer the lactonase SsoPox from Sulfolobus solfataricus into a phosphotriesterase. The five best variants were characterized and their structure was solved. The most active variant, αsD6 (V27A-Y97W-L228M-W263M) demonstrates a large increase in catalytic efficiencies over the wild-type enzyme, with increases of 2,210-fold, 163-fold, 58-fold, 16-fold against methyl-parathion, malathion, ethyl-paraoxon, and methyl-paraoxon, respectively. Interestingly, the best mutants are also capable of degrading fensulfothion, which is reported to be an inhibitor for the wild-type enzyme, as well as others that are not substrates of the starting template or previously reported W263 mutants. The broad specificity of these engineered variants makes them promising candidates for the bioremediation of organophosphorus compounds. Analysis of their structures reveals that the increase in activity mainly occurs through the destabilization of the active site loop involved in substrate binding, and it has been observed that the level of disorder correlates with the width of the enzyme specificity spectrum. This finding supports the idea that active site conformational flexibility is essential to the acquisition of broader substrate specificity.
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Affiliation(s)
- Pauline Jacquet
- CNRS UMR 7278, IRD198, INSERM U1095, APHM, Institut Hospitalier Universitaire Méditerranée-Infection, Aix-Marseille Université, 19-21 Bd Jean Moulin, 13005, Marseille, France
| | - Julien Hiblot
- CNRS UMR 7278, IRD198, INSERM U1095, APHM, Institut Hospitalier Universitaire Méditerranée-Infection, Aix-Marseille Université, 19-21 Bd Jean Moulin, 13005, Marseille, France
- MPI for Medical Research, Chemical Biology department (EPFL), Heidelberg, Germany
| | - David Daudé
- Gene&GreenTK, IHU Méditerranée Infection, 19-21 Bd Jean Moulin, 13005, Marseille, France
| | - Céline Bergonzi
- CNRS UMR 7278, IRD198, INSERM U1095, APHM, Institut Hospitalier Universitaire Méditerranée-Infection, Aix-Marseille Université, 19-21 Bd Jean Moulin, 13005, Marseille, France
- University of Minnesota, Department of Biochemistry, Molecular Biology and Biophysics & Biotechnology Institute, St. Paul, MN, 55108, USA
| | - Guillaume Gotthard
- CNRS UMR 7278, IRD198, INSERM U1095, APHM, Institut Hospitalier Universitaire Méditerranée-Infection, Aix-Marseille Université, 19-21 Bd Jean Moulin, 13005, Marseille, France
| | - Nicholas Armstrong
- CNRS UMR 7278, IRD198, INSERM U1095, APHM, Institut Hospitalier Universitaire Méditerranée-Infection, Aix-Marseille Université, 19-21 Bd Jean Moulin, 13005, Marseille, France
| | - Eric Chabrière
- CNRS UMR 7278, IRD198, INSERM U1095, APHM, Institut Hospitalier Universitaire Méditerranée-Infection, Aix-Marseille Université, 19-21 Bd Jean Moulin, 13005, Marseille, France.
| | - Mikael Elias
- University of Minnesota, Department of Biochemistry, Molecular Biology and Biophysics & Biotechnology Institute, St. Paul, MN, 55108, USA.
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17
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Zhang Y, An J, Yang GY, Bai A, Zheng B, Lou Z, Wu G, Ye W, Chen HF, Feng Y, Manco G. Active site loop conformation regulates promiscuous activity in a lactonase from Geobacillus kaustophilus HTA426. PLoS One 2015; 10:e0115130. [PMID: 25706379 PMCID: PMC4338136 DOI: 10.1371/journal.pone.0115130] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 11/19/2014] [Indexed: 02/02/2023] Open
Abstract
Enzyme promiscuity is a prerequisite for fast divergent evolution of biocatalysts. A phosphotriesterase-like lactonase (PLL) from Geobacillus kaustophilus HTA426 (GkaP) exhibits main lactonase and promiscuous phosphotriesterase activities. To understand its catalytic and evolutionary mechanisms, we investigated a “hot spot” in the active site by saturation mutagenesis as well as X-ray crystallographic analyses. We found that position 99 in the active site was involved in substrate discrimination. One mutant, Y99L, exhibited 11-fold improvement over wild-type in reactivity (kcat/Km) toward the phosphotriesterase substrate ethyl-paraoxon, but showed 15-fold decrease toward the lactonase substrate δ-decanolactone, resulting in a 157-fold inversion of the substrate specificity. Structural analysis of Y99L revealed that the mutation causes a ∼6.6 Å outward shift of adjacent loop 7, which may cause increased flexibility of the active site and facilitate accommodation and/or catalysis of organophosphate substrate. This study provides for the PLL family an example of how the evolutionary route from promiscuity to specificity can derive from very few mutations, which promotes alteration in the conformational adjustment of the active site loops, in turn draws the capacity of substrate binding and activity.
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Affiliation(s)
- Yu Zhang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, Jilin University, Changchun, People’s Republic of China
- Environmental Science Research and Design Institute of Zhejiang Province, Hangzhou, People’s Republic of China
| | - Jiao An
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, Jilin University, Changchun, People’s Republic of China
| | - Guang-Yu Yang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
| | - Aixi Bai
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, Jilin University, Changchun, People’s Republic of China
| | - Baisong Zheng
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, Jilin University, Changchun, People’s Republic of China
| | - Zhiyong Lou
- Laboratory of Structural Biology, School of Medicine, Tsinghua University, Beijing, People’s Republic of China
| | - Geng Wu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
| | - Wei Ye
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
| | - Hai-Feng Chen
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
| | - Yan Feng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, Jilin University, Changchun, People’s Republic of China
- * E-mail: (YF); (GM)
| | - Giuseppe Manco
- Institute of Protein Biochemistry, National Research Council, Naples, Italy
- * E-mail: (YF); (GM)
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18
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Bzdrenga J, Hiblot J, Gotthard G, Champion C, Elias M, Chabriere E. SacPox from the thermoacidophilic crenarchaeon Sulfolobus acidocaldarius is a proficient lactonase. BMC Res Notes 2014; 7:333. [PMID: 24894602 PMCID: PMC4068969 DOI: 10.1186/1756-0500-7-333] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 05/27/2014] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND SacPox, an enzyme from the extremophilic crenarchaeal Sulfolobus acidocaldarius (Sac), was isolated by virtue of its phosphotriesterase (or paraoxonase; Pox) activity, i.e. its ability to hydrolyze the neurotoxic organophosphorus insecticides. Later on, SacPox was shown to belong to the Phosphotriesterase-Like Lactonase family that comprises natural lactonases, possibly involved in quorum sensing, and endowed with promiscuous, phosphotriesterase activity. RESULTS Here, we present a comprehensive and broad enzymatic characterization of the natural lactonase and promiscuous organophosphorus hydrolase activities of SacPox, as well as a structural analysis using a model. CONCLUSION Kinetic experiments show that SacPox is a proficient lactonase, including at room temperature. Moreover, we discuss the observed differences in substrate specificity between SacPox and its closest homologues SsoPox and SisLac together with the possible structural causes for these observations.
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Affiliation(s)
- Janek Bzdrenga
- URMITE UMR CNRS-IRD 6236, IFR48, Faculté de Médecine et de Pharmacie, Université de la Méditerranée, Marseille, France
| | - Julien Hiblot
- URMITE UMR CNRS-IRD 6236, IFR48, Faculté de Médecine et de Pharmacie, Université de la Méditerranée, Marseille, France
| | - Guillaume Gotthard
- URMITE UMR CNRS-IRD 6236, IFR48, Faculté de Médecine et de Pharmacie, Université de la Méditerranée, Marseille, France
| | - Charlotte Champion
- URMITE UMR CNRS-IRD 6236, IFR48, Faculté de Médecine et de Pharmacie, Université de la Méditerranée, Marseille, France
| | - Mikael Elias
- Weizmann Institute of Science, Biological Chemistry, Rehovot, Israel
| | - Eric Chabriere
- URMITE UMR CNRS-IRD 6236, IFR48, Faculté de Médecine et de Pharmacie, Université de la Méditerranée, Marseille, France
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19
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Kallnik V, Bunescu A, Sayer C, Bräsen C, Wohlgemuth R, Littlechild J, Siebers B. Characterization of a phosphotriesterase-like lactonase from the hyperthermoacidophilic crenarchaeon Vulcanisaeta moutnovskia. J Biotechnol 2014; 190:11-7. [PMID: 24858677 DOI: 10.1016/j.jbiotec.2014.04.026] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 04/17/2014] [Accepted: 04/29/2014] [Indexed: 11/15/2022]
Abstract
The phosphotriesterase-like lactonase (PLL) encoded by Vmut_2255 in the hyperthermoacidophilic crenarchaeon Vulcanisaeta moutnovskia (VmutPLL), represents the only hyperthermophilic PLL homologue identified so far in addition to the previously characterized thermophilic PLLs from Sulfolobus spp. The Vmut_2255 gene was cloned, heterologously expressed in Escherichia coli; the resultant protein purified and characterized as a 82kDa homodimer (36kDa subunits). The VmutPLL converted lactones and acyl-homoserine lactones (AHLs) with comparable activities. Towards organophosphates (OP) VmutPLL showed a promiscuous but significantly lower activity and only minor activity was observed with carboxylesters. The catalytic activity strictly depended on bivalent cations (Cd(2+)>Ni(2+)>Co(2+)>Mn(2+)>Zn(2+)). Furthermore, VmutPLL showed a pH optimum around 8.0, a temperature optimum of 80°C, and thermostability with a half-life of 26min at 90°C. In this work, the stereoselectivity of a PLL enzyme was investigated for the first time using enantiopure lactones. The VmutPLL showed a slight preference but not an exclusive specificity for the (R)-enantiomers of capro- and valerolactone. The high thermal stability as well as the broad substrate spectrum towards lactones, AHLs and OPs underlines the high biotechnological potential of VmutPLL.
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Affiliation(s)
- Verena Kallnik
- Molecular Enzyme Technology and Biochemistry, Biofilm Centre, Faculty of Chemistry, University of Duisburg-Essen, Universitaetsstrasse 5, 45141 Essen, Germany.
| | - Alina Bunescu
- Sigma-Aldrich, Riedstraße 2, D-89555 Steinheim, Germany
| | - Christopher Sayer
- The Henry Wellcome Building for Biocatalysis, Biosciences, College of Life and Environmental Sciences, University of Exeter, United Kingdom
| | - Christopher Bräsen
- Molecular Enzyme Technology and Biochemistry, Biofilm Centre, Faculty of Chemistry, University of Duisburg-Essen, Universitaetsstrasse 5, 45141 Essen, Germany
| | | | - Jennifer Littlechild
- The Henry Wellcome Building for Biocatalysis, Biosciences, College of Life and Environmental Sciences, University of Exeter, United Kingdom
| | - Bettina Siebers
- Molecular Enzyme Technology and Biochemistry, Biofilm Centre, Faculty of Chemistry, University of Duisburg-Essen, Universitaetsstrasse 5, 45141 Essen, Germany
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20
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Zhan D, Zhou Z, Guan S, Han W. The effect of conformational variability of phosphotriesterase upon N-acyl-L-homoserine lactone and paraoxon binding: insights from molecular dynamics studies. Molecules 2013; 18:15501-18. [PMID: 24352010 PMCID: PMC6269825 DOI: 10.3390/molecules181215501] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 12/03/2013] [Accepted: 12/06/2013] [Indexed: 11/16/2022] Open
Abstract
The organophosphorous hydrolase (PTE) from Brevundimonas diminuta is capable of degrading extremely toxic organophosphorous compounds with a high catalytic turnover and broad substrate specificity. Although the natural substrate for PTE is unknown, its loop remodeling (loop 7-2/H254R) led to the emergence of a homoserine lactonase (HSL) activity that is undetectable in PTE (kcat/km values of up to 2 × 10(4)), with only a minor decrease in PTE paraoxonase activity. In this study, homology modeling and molecular dynamics simulations have been undertaken seeking to explain the reason for the substrate specificity for the wild-type and the loop 7-2/H254R variant. The cavity volume estimated results showed that the active pocket of the variant was almost two fold larger than that of the wild-type (WT) enzyme. pKa calculations for the enzyme (the WT and the variant) showed a significant pKa shift from WT standard values (ΔpKa = 3.5 units) for the His254 residue (in the Arg254 variant). Molecular dynamics simulations indicated that the displacement of loops 6 and 7 over the active site in loop 7-2/H254R variant is useful for N-acyl-L-homoserine lactone (C4-HSL) with a large aliphatic chain to site in the channels easily. Thence the expanding of the active pocket is beneficial to C4-HSL binding and has a little effect on paraoxon binding. Our results provide a new theoretical contribution of loop remodeling to the rapid divergence of new enzyme functions.
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Affiliation(s)
- Dongling Zhan
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, Jilin University, Changchun 130023, China; E-Mail:
- College of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, China
| | - Zhenhuan Zhou
- Jilin Provincial Research Institute of Population and Life sciences, Changchun 130041, China; E-Mail:
| | - Shanshan Guan
- State Key Laboratory of Theoretical and Computational Chemistry, Jilin University, Changchun 130023, China; E-Mail:
| | - Weiwei Han
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, Jilin University, Changchun 130023, China; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel./Fax: +86-431-8515-5218
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Hiblot J, Gotthard G, Elias M, Chabriere E. Differential active site loop conformations mediate promiscuous activities in the lactonase SsoPox. PLoS One 2013; 8:e75272. [PMID: 24086491 PMCID: PMC3781021 DOI: 10.1371/journal.pone.0075272] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 08/14/2013] [Indexed: 11/19/2022] Open
Abstract
Enzymes are proficient catalysts that enable fast rates of Michaelis-complex formation, the chemical step and products release. These different steps may require different conformational states of the active site that have distinct binding properties. Moreover, the conformational flexibility of the active site mediates alternative, promiscuous functions. Here we focused on the lactonase SsoPox from Sulfolobus solfataricus. SsoPox is a native lactonase endowed with promiscuous phosphotriesterase activity. We identified a position in the active site loop (W263) that governs its flexibility, and thereby affects the substrate specificity of the enzyme. We isolated two different sets of substitutions at position 263 that induce two distinct conformational sampling of the active loop and characterized the structural and kinetic effects of these substitutions. These sets of mutations selectively and distinctly mediate the improvement of the promiscuous phosphotriesterase and oxo-lactonase activities of SsoPox by increasing active-site loop flexibility. These observations corroborate the idea that conformational diversity governs enzymatic promiscuity and is a key feature of protein evolvability.
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Affiliation(s)
- Julien Hiblot
- URMITE UMR CNRS-IRD 6236, Faculté de Médecine et de Pharmacie, Université de la Méditerranée, Marseille, France
| | - Guillaume Gotthard
- URMITE UMR CNRS-IRD 6236, Faculté de Médecine et de Pharmacie, Université de la Méditerranée, Marseille, France
| | - Mikael Elias
- Weizmann Institute of Science, Biological Chemistry, Rehovot, Israel
| | - Eric Chabriere
- URMITE UMR CNRS-IRD 6236, Faculté de Médecine et de Pharmacie, Université de la Méditerranée, Marseille, France
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22
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Mandrich L, Di Gennaro S, Palma A, Manco G. A further biochemical characterization of DrPLL the thermophilic lactonase from Deinococcus radiodurans. Protein Pept Lett 2013; 20:36-44. [PMID: 22789107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 06/14/2012] [Accepted: 06/14/2012] [Indexed: 06/01/2023]
Abstract
Recently, the cloning of the ORF Dr0930 from Deinococcus radiodurans displaying, as primary activity, a lactonase activity and a promiscuous phosphotriesterase activity was reported. The crystal structure of the resulting recombinant enzyme has been solved, and many mutants have been generated in order to increase the phosphotriesterase activity, with the aim to reach the level of activity of the related pPTE from Pseudomonas diminuta. In this paper we report an additional biochemical characterization of DrPLL and show that this enzyme has an optimal temperature for catalysis of 85 °C and possesses promiscuous carboxylesterase, phophodiesterase and thioesterase activities which were not previously described. A metal analysis was performed on the purified protein by inductively coupled plasma mass spectrometry (ICP-MS ELAN DRC-e), which confirmed the presence of Ni(2+) as a main metal in the recombinant protein. Surprisingly, the specificity constants (s=k(cat)/K(M)) for the pNP-decanoate and pNP-dodecanoate esters were only one order of magnitude lower than that for the lactone substrate thio-buthyl-γ-butyric-lactone (TBBL), and the K(M) value for TBBL was more than ten-fold higher than those for the esters. We named this enzyme DrPLL, based on its structural and biochemical features it belongs to the Phosphotriesterase Like Lactonase group, a small protein family belonging to the amidohydrolase superfamily.
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Affiliation(s)
- Luigi Mandrich
- Institute of Protein Biochemistry (IBP), National Research Council (CNR), Naples, Italy.
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23
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Hiblot J, Gotthard G, Chabriere E, Elias M. Structural and enzymatic characterization of the lactonase SisLac from Sulfolobus islandicus. PLoS One 2012; 7:e47028. [PMID: 23071703 PMCID: PMC3468530 DOI: 10.1371/journal.pone.0047028] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Accepted: 09/07/2012] [Indexed: 11/19/2022] Open
Abstract
Background A new member of the Phosphotriesterase-Like Lactonases (PLL) family from the hyperthermophilic archeon Sulfolobus islandicus (SisLac) has been characterized. SisLac is a native lactonase that exhibits a high promiscuous phosphotriesterase activity. SisLac thus represents a promising target for engineering studies, exhibiting both detoxification and bacterial quorum quenching abilities, including human pathogens such as Pseudomonas aeruginosa. Methodology/Principal Findings Here, we describe the substrate specificity of SisLac, providing extensive kinetic studies performed with various phosphotriesters, esters, N-acyl-homoserine lactones (AHLs) and other lactones as substrates. Moreover, we solved the X-ray structure of SisLac and structural comparisons with the closely related SsoPox structure highlighted differences in the surface salt bridge network and the dimerization interface. SisLac and SsoPox being close homologues (91% sequence identity), we undertook a mutational study to decipher these structural differences and their putative consequences on the stability and the catalytic properties of these proteins. Conclusions/Significance We show that SisLac is a very proficient lactonase against aroma lactones and AHLs as substrates. Hence, data herein emphasize the potential role of SisLac as quorum quenching agent in Sulfolobus. Moreover, despite the very high sequence homology with SsoPox, we highlight key epistatic substitutions that influence the enzyme stability and activity.
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Affiliation(s)
- Julien Hiblot
- URMITE UMR CNRS-IRD 6236, IFR48, Faculté de Médecine et de Pharmacie, Université de la Méditerranée, Marseille, France
| | - Guillaume Gotthard
- URMITE UMR CNRS-IRD 6236, IFR48, Faculté de Médecine et de Pharmacie, Université de la Méditerranée, Marseille, France
| | - Eric Chabriere
- URMITE UMR CNRS-IRD 6236, IFR48, Faculté de Médecine et de Pharmacie, Université de la Méditerranée, Marseille, France
- * E-mail: (EC); (ME)
| | - Mikael Elias
- Weizmann Institute of Science, Biological Chemistry, Rehovot, Israel
- * E-mail: (EC); (ME)
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Allen BL, Johnson JD, Walker JP. Hydrolase stabilization via entanglement in poly(propylene sulfide) nanoparticles: stability towards reactive oxygen species. Nanotechnology 2012; 23:294009. [PMID: 22743846 DOI: 10.1088/0957-4484/23/29/294009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In the advancement of green syntheses and sustainable reactions, enzymatic biocatalysis offers extremely high reaction rates and selectivity that goes far beyond the reach of chemical catalysts; however, these enzymes suffer from typical environmental constraints, e.g. operational temperature, pH and tolerance to oxidative environments. A common hydrolase enzyme, diisopropylfluorophosphatase (DFPase, EC 3.1.8.2), has demonstrated a pronounced efficacy for the hydrolysis of a variety of substrates for potential toxin remediation, but suffers from the aforementioned limitations. As a means to enhance DFPase's stability in oxidative environments, enzymatic covalent immobilization within the polymeric matrix of poly(propylene sulfide) (PPS) nanoparticles was performed. By modifying the enzyme's exposed lysine residues via thiolation, DFPase is utilized as a comonomer/crosslinker in a mild emulsion polymerization. The resultant polymeric polysulfide shell acts as a 'sacrificial barrier' by first oxidizing to polysulfoxides and polysulfones, rendering DFPase in an active state. DFPase-PPS nanoparticles thus retain activity upon exposure to as high as 50 parts per million (ppm) of hypochlorous acid (HOCl), while native DFPase is observed as inactive at 500 parts per billion (ppb). This trend is also confirmed by enzyme-generated (chloroperoxidase (CPO), EC 1.11.1.10) reactive oxygen species (ROS) including both HOCl (3 ppm) and ClO(2) (100 ppm).
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Affiliation(s)
- Brett L Allen
- FLIR Systems, Inc., 2240 William Pitt Way, Pittsburgh, PA 15238, USA.
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25
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Efimov VA, Aralov AV, Chakhmakhcheva OG. [Methoxymethyl and (p-nitrobenzyloxy)methyl groups in the synthesis of oligoribonucleotides by the phosphotriester method]. Bioorg Khim 2011; 37:284-288. [PMID: 21721262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
An efficient synthetic method for monomer ribonucleotide synthons containing 2'-O-methoxymethyl and 2'O-(p-nitrobenzyloxy)methyl groups used for oligonucleotide phosphotriester method with O-nucleophilic intramolecular catalysis at the stage of formation of internucleotide bond is developed. It is shown that synthons containing protecting 2'-O-(p-nitrobenzyloxy)methyl group may be used for automatic synthesis of phosphotriester oligoribonucleotides with high yields and synthons containing methoxymethyl group--to get 2'-O-modified oligonucleotides.
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26
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Ng FSW, Wright DM, Seah SYK. Characterization of a phosphotriesterase-like lactonase from Sulfolobus solfataricus and its immobilization for disruption of quorum sensing. Appl Environ Microbiol 2011; 77:1181-6. [PMID: 21183649 PMCID: PMC3067241 DOI: 10.1128/aem.01642-10] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Accepted: 12/13/2010] [Indexed: 11/20/2022] Open
Abstract
SsoPox, a bifunctional enzyme with organophosphate hydrolase and N-acyl homoserine lactonase activities from the hyperthermophilic archaeon Sulfolobus solfataricus, was overexpressed and purified from recombinant Pseudomonas putida KT2440 with a yield of 9.4 mg of protein per liter of culture. The enzyme has a preference for N-acyl homoserine lactones (AHLs) with acyl chain lengths of at least 8 carbon atoms, mainly due to lower K(m) values for these substrates. The highest specificity constant obtained was for N-3-oxo-decanoyl homoserine lactone (k(cat)/K(m) = 5.5 × 10(3) M(-1)·s(-1)), but SsoPox can also degrade N-butyryl homoserine lactone (C(4)-HSL) and N-oxo-dodecanoyl homoserine lactone (oxo-C(12)-HSL), which are important for quorum sensing in our Pseudomonas aeruginosa model system. When P. aeruginosa PAO1 cultures were grown in the presence of SsoPox-immobilized membranes, the production of C(4)-HSL- and oxo-C(12)-HSL-regulated virulence factors, elastase, protease, and pyocyanin were significantly reduced. This is the first demonstration that immobilized quorum-quenching enzymes can be used to attenuate the production of virulence factors controlled by quorum-sensing signals.
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Affiliation(s)
- Filomena S W Ng
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
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27
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Merone L, Mandrich L, Porzio E, Rossi M, Müller S, Reiter G, Worek F, Manco G. Improving the promiscuous nerve agent hydrolase activity of a thermostable archaeal lactonase. Bioresour Technol 2010; 101:9204-9212. [PMID: 20667718 DOI: 10.1016/j.biortech.2010.06.102] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Revised: 06/16/2010] [Accepted: 06/24/2010] [Indexed: 05/29/2023]
Abstract
The thermostable Phosphotriesterase-Like Lactonase from Sulfolobus solfataricus (SsoPox) hydrolyzes lactones and, at a lower rate, neurotoxic organophosphorus compounds. The persistent demand of detoxification tools in the field of agricultural wastes and restoring of conditions after terrorist acts prompted us to exploit SsoPox as a "starter" to evolve its ancillary nerve agents hydrolytic capability. A directed evolution strategy yielded, among several variants, the single mutant W263F with k(cat) and specificity constant against paraoxon 16- and 6-fold enhanced, respectively, compared to the wild type. Furthermore, a phenomenon of enzyme activation by SDS has been observed, which allowed to increase those values 150- and 28-fold, respectively. The activity of SsoPox against the deadly nerve gas Cyclosarin has been reported for the first time and proved to be substantially unaffected for variant W263F. Finally, outperforming efficiency of W263F was demonstrated, under severe stressing conditions, with respect to the best known phosphotriesterase PTE from Brevundimonas diminuta.
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Affiliation(s)
- Luigia Merone
- Istituto di Biochimica delle Proteine, Consiglio Nazionale delle Ricerche, Via P. Castellino 111, 80131 Naples, Italy
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Chen JCH, Mustyakimov M, Schoenborn BP, Langan P, Blum MM. Neutron structure and mechanistic studies of diisopropyl fluorophosphatase (DFPase). Acta Crystallogr D Biol Cryst 2010; 66:1131-8. [PMID: 21041927 PMCID: PMC2967418 DOI: 10.1107/s0907444910034013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Accepted: 08/23/2010] [Indexed: 11/10/2022]
Abstract
Diisopropyl fluorophosphatase (DFPase) is a calcium-dependent phosphotriesterase that acts on a variety of highly toxic organophosphorus compounds that act as inhibitors of acetylcholinesterase. The mechanism of DFPase has been probed using a variety of methods, including isotopic labelling, which demonstrated the presence of a phosphoenzyme intermediate in the reaction mechanism. In order to further elucidate the mechanism of DFPase and to ascertain the protonation states of the residues and solvent molecules in the active site, the neutron structure of DFPase was solved at 2.2 Å resolution. The proposed nucleophile Asp229 is deprotonated, while the active-site solvent molecule W33 was identified as water and not hydroxide. These data support a mechanism involving direct nucleophilic attack by Asp229 on the substrate and rule out a mechanism involving metal-assisted water activation. These data also allowed for the re-engineering of DFPase through rational design to bind and productively orient the more toxic S(P) stereoisomers of the nerve agents sarin and cyclosarin, creating a modified enzyme with enhanced overall activity and significantly increased detoxification properties.
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Affiliation(s)
- Julian C H Chen
- Institute of Biophysical Chemistry, Goethe University Frankfurt, Max-von-Laue-Strasse 9, 60438 Frankfurt, Germany.
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Abstract
In the last decades the idea to use enzymes for environmental bioremediation has been more and more proposed and, in the light of this, new solutions have been suggested and detailed studies on some classes of enzymes have been performed. In particular, our attention in the last few years has been focused on the enzymes belonging to the amidohydrolase superfamily. Several members of this superfamily are endowed with promiscuous activities. The term 'catalytic promiscuity' describes the capability of an enzyme to catalyse different chemical reactions, called secondary activities, at the active site responsible for the main activity. Recently, a new family of microbial lactonases with promiscuous phosphotriesterase activity, dubbed PTE-Like Lactonase (PLL), has been ascribed to the amidohydrolase superfamily. Among members of this family are enzymes found in the archaea Sulfolobus solfataricus and Sulfolobus acidocaldarius, which show high thermophilicity and thermal resistance. Enzymes showing phosphotriesterase activity are attractive from a biotechnological point of view because they are capable of hydrolysing the organophosphate phosphotriesters (OPs), a class of synthetic compounds employed worldwide both as insecticides and chemical warfare agents. Furthermore, from a basic point of view, studies of catalytic promiscuity offer clues to understand natural evolution of enzymes and to translate this into in vitro adaptation of enzymes to specific human needs. Thermostable enzymes able to hydrolyse OPs are considered good candidates for the set-up of efficient detoxification tools.
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Affiliation(s)
- Luigi Mandrich
- Institute of Protein Biochemistry (IBP), National Research Council (CNR), Naples, Italy
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30
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Istamboulie G, Durbiano R, Fournier D, Marty JL, Noguer T. Biosensor-controlled degradation of chlorpyrifos and chlorfenvinfos using a phosphotriesterase-based detoxification column. Chemosphere 2010; 78:1-6. [PMID: 19906400 DOI: 10.1016/j.chemosphere.2009.10.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Revised: 10/14/2009] [Accepted: 10/15/2009] [Indexed: 05/28/2023]
Abstract
This works presents the development of a detoxification system based on bacterial phosphotriesterase (PTE) for the degradation of organophosphate (OP) insecticides in water. PTE was immobilised on an activated agarose gel via covalent coupling. Two different OPs were studied, chlorpyrifos and chlorfenvinfos, due to their importance in the field of water policy. The efficiency of insecticide degradation was controlled using a highly sensitive biosensor allowing the detection of OP concentration as low as 0.004 microgL(-1). Under optimum conditions, it was shown that a column incorporating 500IU of PTE was suitable for the detoxification of solutions containing either isolated pesticides or pesticides mixtures, even at concentrations higher than authorized limits. Finally, the method was shown to be adapted to the decontamination of real samples of pesticides with concentrations up to 20 microgL(-1).
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Affiliation(s)
- Georges Istamboulie
- IMAGES, EA4218, Building S, Université de Perpignan Via Domitia, 66860 Perpignan cedex, France
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31
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Jiang L, Cai J, Wang J, Liang S, Xu Z, Yang ST. Phosphoenolpyruvate-dependent phosphorylation of sucrose by Clostridium tyrobutyricum ZJU 8235: evidence for the phosphotransferase transport system. Bioresour Technol 2010; 101:304-309. [PMID: 19726178 DOI: 10.1016/j.biortech.2009.08.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Revised: 07/25/2009] [Accepted: 08/06/2009] [Indexed: 05/28/2023]
Abstract
The uptake and metabolism of sucrose, the major sugar in industrial cane molasses, by Clostridium tyrobutyricum ZJU 8235 was investigated and this study provided the first definitive evidence for phosphoenolpyruvate (PEP)-dependent phosphotransferase system (PTS) activity in butyric acid-producing bacteria. Glucose was utilized preferentially to sucrose when both substrates were present in the medium. The PEP-dependent sucrose: PTS was induced by growing C. tyrobutyricum on sucrose (but not glucose) as the sole carbon source. Extract fractionation and PTS reconstitution experiments revealed that both soluble and membrane components were required for bioactivity. Sucrose-6-phosphate hydrolase and fructokinase activities were also detected in sucrose-grown cultures. Based on these findings, a pathway of sucrose metabolism in this organism was proposed that includes the forming of sucrose-6-phosphate via the PTS and its further degradation into glucose-6-phosphate and fructose-6-phosphate.
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Affiliation(s)
- Ling Jiang
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, PR China
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32
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Zhang X, Wu R, Song L, Lin Y, Lin M, Cao Z, Wu W, Mo Y. Molecular dynamics simulations of the detoxification of paraoxon catalyzed by phosphotriesterase. J Comput Chem 2009; 30:2388-401. [PMID: 19353598 PMCID: PMC2754597 DOI: 10.1002/jcc.21238] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Combined QM(PM3)/MM molecular dynamics simulations together with QM(DFT)/MM optimizations for key configurations have been performed to elucidate the enzymatic catalysis mechanism on the detoxification of paraoxon by phosphotriesterase (PTE). In the simulations, the PM3 parameters for the phosphorous atom were reoptimized. The equilibrated configuration of the enzyme/substrate complex showed that paraoxon can strongly bind to the more solvent-exposed metal ion Zn(beta), but the free energy profile along the binding path demonstrated that the binding is thermodynamically unfavorable. This explains why the crystal structures of PTE with substrate analogues often exhibit long distances between the phosphoral oxygen and Zn(beta). The subsequent SN2 reaction plays the key role in the whole process, but controversies exist over the identity of the nucleophilic species, which could be either a hydroxide ion terminally coordinated to Zn(alpha) or the micro-hydroxo bridge between the alpha- and beta-metals. Our simulations supported the latter and showed that the rate-limiting step is the distortion of the bound paraoxon to approach the bridging hydroxide. After this preparation step, the bridging hydroxide ion attacks the phosphorous center and replaces the diethyl phosphate with a low barrier. Thus, a plausible way to engineer PTE with enhanced catalytic activity is to stabilize the deformed paraoxon. Conformational analyses indicate that Trp131 is the closest residue to the phosphoryl oxygen, and mutations to Arg or Gln or even Lys, which can shorten the hydrogen bond distance with the phosphoryl oxygen, could potentially lead to a mutant with enhanced activity for the detoxification of organophosphates.
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Affiliation(s)
- Xin Zhang
- Department of Chemistry, Western Michigan University, Kalamazoo, MI 49008, USA
- Department of Chemistry, College of Chemistry and Chemical Engineering, the State Key Laboratory for Physical Chemistry of Solid States, Center for Theoretical Chemistry, Xiamen University, Xiamen, Fujian 361005, P. R. China
| | - Ruibo Wu
- Department of Chemistry, College of Chemistry and Chemical Engineering, the State Key Laboratory for Physical Chemistry of Solid States, Center for Theoretical Chemistry, Xiamen University, Xiamen, Fujian 361005, P. R. China
| | - Lingchun Song
- Department of Chemistry, Western Michigan University, Kalamazoo, MI 49008, USA
- Department of Chemistry, College of Chemistry and Chemical Engineering, the State Key Laboratory for Physical Chemistry of Solid States, Center for Theoretical Chemistry, Xiamen University, Xiamen, Fujian 361005, P. R. China
| | - Yuchun Lin
- Department of Chemistry, Western Michigan University, Kalamazoo, MI 49008, USA
| | - Menghai Lin
- Department of Chemistry, College of Chemistry and Chemical Engineering, the State Key Laboratory for Physical Chemistry of Solid States, Center for Theoretical Chemistry, Xiamen University, Xiamen, Fujian 361005, P. R. China
| | - Zexing Cao
- Department of Chemistry, College of Chemistry and Chemical Engineering, the State Key Laboratory for Physical Chemistry of Solid States, Center for Theoretical Chemistry, Xiamen University, Xiamen, Fujian 361005, P. R. China
| | - Wei Wu
- Department of Chemistry, College of Chemistry and Chemical Engineering, the State Key Laboratory for Physical Chemistry of Solid States, Center for Theoretical Chemistry, Xiamen University, Xiamen, Fujian 361005, P. R. China
| | - Yirong Mo
- Department of Chemistry, Western Michigan University, Kalamazoo, MI 49008, USA
- Department of Chemistry, College of Chemistry and Chemical Engineering, the State Key Laboratory for Physical Chemistry of Solid States, Center for Theoretical Chemistry, Xiamen University, Xiamen, Fujian 361005, P. R. China
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Hawwa R, Aikens J, Turner RJ, Santarsiero BD, Mesecar AD. Structural basis for thermostability revealed through the identification and characterization of a highly thermostable phosphotriesterase-like lactonase from Geobacillus stearothermophilus. Arch Biochem Biophys 2009; 488:109-20. [PMID: 19615330 DOI: 10.1016/j.abb.2009.06.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2009] [Revised: 06/05/2009] [Accepted: 06/09/2009] [Indexed: 11/18/2022]
Abstract
A new enzyme homologous to phosphotriesterase was identified from the bacterium Geobacillus stearothermophilus (GsP). This enzyme belongs to the amidohydrolase family and possesses the ability to hydrolyze both lactone and organophosphate (OP) compounds, making it a phosphotriesterase-like lactonase (PLL). GsP possesses higher OP-degrading activity than recently characterized PLLs, and it is extremely thermostable. GsP is active up to 100 degrees C with an energy of activation of 8.0 kcal/mol towards ethyl paraoxon, and it can withstand an incubation temperature of 60 degrees C for two days. In an attempt to understand the thermostability of PLLs, the X-ray structure of GsP was determined and compared to those of existing PLLs. Based upon a comparative analysis, a new thermal advantage score and plot was developed and reveals that a number of different factors contribute to the thermostability of PLLs.
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Affiliation(s)
- Renda Hawwa
- Department of Medicinal Chemistry and Pharmacognosy and the Center for Pharmaceutical Biotechnology, University of Illinois at Chicago, Chicago, IL 60607, USA
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Xiang DF, Kolb P, Fedorov AA, Meier MM, Fedorov EV, Nguyen TT, Sterner R, Almo SC, Shoichet BK, Raushel FM. Functional annotation and three-dimensional structure of Dr0930 from Deinococcus radiodurans, a close relative of phosphotriesterase in the amidohydrolase superfamily. Biochemistry 2009; 48:2237-47. [PMID: 19159332 PMCID: PMC3176505 DOI: 10.1021/bi802274f] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dr0930, a member of the amidohydrolase superfamily in Deinococcus radiodurans, was cloned, expressed, and purified to homogeneity. The enzyme crystallized in the space group P3121, and the structure was determined to a resolution of 2.1 A. The protein folds as a (beta/alpha)7beta-barrel, and a binuclear metal center is found at the C-terminal end of the beta-barrel. The purified protein contains a mixture of zinc and iron and is intensely purple at high concentrations. The purple color was determined to be due to a charge transfer complex between iron in the beta-metal position and Tyr-97. Mutation of Tyr-97 to phenylalanine or complexation of the metal center with manganese abolished the absorbance in the visible region of the spectrum. Computational docking was used to predict potential substrates for this previously unannotated protein. The enzyme was found to catalyze the hydrolysis of delta- and gamma-lactones with an alkyl substitution at the carbon adjacent to the ring oxygen. The best substrate was delta-nonanoic lactone with a kcat/Km of 1.6 x 10(6) M-1 s-1. Dr0930 was also found to catalyze the very slow hydrolysis of paraoxon with values of kcat and kcat/Km of 0.07 min-1 and 0.8 M-1 s-1, respectively. The amino acid sequence identity to the phosphotriesterase (PTE) from Pseudomonas diminuta is 30%. The eight substrate specificity loops were transplanted from PTE to Dr0930, but no phosphotriesterase activity could be detected in the chimeric PTE-Dr0930 hybrid. Mutation of Phe-26 and Cys-72 in Dr0930 to residues found in the active site of PTE enhanced the kinetic constants for the hydrolysis of paraoxon. The F26G/C72I mutant catalyzed the hydrolysis of paraoxon with a kcat of 1.14 min-1, an increase of 16-fold over the wild-type enzyme. These results support previous proposals that phosphotriesterase activity evolved from an ancestral parent enzyme possessing lactonase activity.
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Affiliation(s)
- Dao Feng Xiang
- Department of Chemistry, P.O. Box 30012, Texas A&M University, College Station, Texas 77842-3012
| | - Peter Kolb
- Department of Pharmaceutical Chemistry, University of California, San Francisco, MC 2550 1700 4 Street, San Francisco, California 94158-2330
| | - Alexander A. Fedorov
- Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461
| | - Monika M. Meier
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, Universitätsstrasse 31, D93053 Regensburg, Germany
| | - Elena V. Fedorov
- Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461
| | - Tinh T. Nguyen
- Department of Chemistry, P.O. Box 30012, Texas A&M University, College Station, Texas 77842-3012
| | - Reinhard Sterner
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, Universitätsstrasse 31, D93053 Regensburg, Germany
| | - Steven C. Almo
- Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461
| | - Brian K. Shoichet
- Department of Pharmaceutical Chemistry, University of California, San Francisco, MC 2550 1700 4 Street, San Francisco, California 94158-2330
| | - Frank M. Raushel
- Department of Chemistry, P.O. Box 30012, Texas A&M University, College Station, Texas 77842-3012
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Ghanem E, Li Y, Xu C, Raushel FM. Characterization of a phosphodiesterase capable of hydrolyzing EA 2192, the most toxic degradation product of the nerve agent VX. Biochemistry 2007; 46:9032-40. [PMID: 17630782 DOI: 10.1021/bi700561k] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Glycerophosphodiesterase (GpdQ) from Enterobacter aerogenes is a nonspecific diesterase that enables Escherichia coli to utilize alkyl phosphodiesters, such as diethyl phosphate, as the sole phosphorus source. The catalytic properties of GpdQ were determined, and the best substrate found was bis(p-nitrophenyl) phosphate with a kcat/Km value of 6.7 x 10(3) M-1 s-1. In addition, the E. aerogenes diesterase was tested as a catalyst for the hydrolysis of a series of phosphonate monoesters which are the hydrolysis products of the highly toxic organophosphonate nerve agents sarin, soman, GF, VX, and rVX. Among the phosphonate monoesters tested, the hydrolysis product of rVX, isobutyl methyl phosphonate, was the best substrate with a kcat/Km value of 33 M-1 s-1. The ability of GpdQ to hydrolyze the phosphonate monoesters provides an alternative selection strategy in the search of enhanced variants of the bacterial phosphotriesterase (PTE) for the hydrolysis of organophosphonate nerve agents. This investigation demonstrated that the previously reported activity of GpdQ toward the hydrolysis of methyl demeton-S is due to the presence of a diester contaminant in the commercial material. Furthermore, it was shown that GpdQ is capable of hydrolyzing a close analogue of EA 2192, the most toxic and persistent degradation product of the nerve agent VX.
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Affiliation(s)
- Eman Ghanem
- Department of Chemistry, P.O. Box 30012, Texas A&M University, College Station, Texas 77842, USA
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Porzio E, Merone L, Mandrich L, Rossi M, Manco G. A new phosphotriesterase from Sulfolobus acidocaldarius and its comparison with the homologue from Sulfolobus solfataricus. Biochimie 2007; 89:625-36. [PMID: 17337320 DOI: 10.1016/j.biochi.2007.01.007] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2006] [Accepted: 01/22/2007] [Indexed: 11/16/2022]
Abstract
The phosphotriesterase PTE, identified in the soil bacterium Pseudomonas diminuta, is thought to have evolved in the last several decades to degrade the pesticide paraoxon with proficiency approaching the limit of substrate diffusion (k(cat)/K(M) of 4 x 10(7)M(-1)s(-1)). It belongs to the amidohydrolase superfamily, but its evolutionary origin remains obscure. The enzyme has important potentiality in the field of the organophosphate decontamination. Recently we reported on the characterization of an archaeal member of the amidohydrolase superfamily, namely Sulfolobus solfataricus, showing low but significant and extremely thermostable paraoxonase activity (k(cat)/K(M) of 4 x 10(3)M(-1)s(-1)). Looking for other thermostable phosphotriesterases we assayed, among others, crude extracts of Sulfolobus acidocaldarius and detected activity. Since the genome of S. acidocaldarius has been recently reported, we identified there an open reading frame highly related to the S. solfataricus enzyme. The gene was cloned, the protein overexpressed in Escherichia coli, purified, and proven to have paraoxonase activity. A comparative analysis detected some significant differences between the two archaeal enzymes.
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Affiliation(s)
- Elena Porzio
- Istituto di Biochimica delle Proteine, Consiglio Nazionale delle Ricerche, via P. Castellino 111, 80131 Naples, Italy
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Nowlan C, Li Y, Hermann JC, Evans T, Carpenter J, Ghanem E, Shoichet BK, Raushel FM. Resolution of chiral phosphate, phosphonate, and phosphinate esters by an enantioselective enzyme library. J Am Chem Soc 2007; 128:15892-902. [PMID: 17147402 DOI: 10.1021/ja0658618] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An array of 16 enantiomeric pairs of chiral phosphate, phosphonate, and phosphinate esters was used to establish the breadth of the stereoselective discrimination inherent within the bacterial phosphotriesterase and 15 mutant enzymes. For each substrate, the leaving group was 4-hydroxyacetophenone while the other two groups attached to the phosphorus core consisted of an asymmetric mixture of methyl, methoxy, ethyl, ethoxy, isopropoxy, phenyl, phenoxy, cyclohexyl, and cyclohexoxy substituents. For the wild-type enzyme, the relative rates of hydrolysis for the two enantiomers ranged from 3 to 5.4 x 10(5). Various combinations of site-specific mutations within the active site were used to create modified enzymes with alterations in their enantioselective properties. For the single-site mutant enzyme, G60A, the stereoselectivity is enhanced relative to that of the wild-type enzyme by 1-3 orders of magnitude. Additional mutants were obtained where the stereoselectivity is inverted relative to the wild-type enzyme for 13 of the 16 pairs of enantiomers tested for this investigation. The most dramatic example was obtained for the hydrolysis of 4-acetylphenyl methyl phenyl phosphate. The G60A mutant preferentially hydrolyzes the SP-enantiomer by a factor of 3.7 x 10(5). The I106G/F132G/H257Y mutant preferentially hydrolyzes the RP-enantiomer by a factor of 9.7 x 10(2). This represents an enantioselective discrimination of 3.6 x 10(8) between these two mutants, with a total of only four amino acid changes. The rate differential between the two enantiomers for any given mutant enzyme is postulated to be governed by the degree of nonproductive binding within the enzyme active site and stabilization of the transition state. This hypothesis is supported by computational docking of the high-energy, pentavalent form of the substrates to modeled structures of the mutant enzyme; the energies of the docked transition-state analogues qualitatively capture the enantiomeric preferences of the various mutants for the different substrates. These results demonstrate that the catalytic properties of the wild-type phosphotriesterase can be exploited for the kinetic resolution of a wide range of phosphate, phosphonate, and phosphinate esters and that the active site of this enzyme is remarkably amenable to structural perturbations via amino acid substitution.
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Affiliation(s)
- Charity Nowlan
- Department of Chemistry, Texas A&M University, College Station, Texas 77842-3012, USA
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Hermann JC, Ghanem E, Li Y, Raushel FM, Irwin JJ, Shoichet BK. Predicting substrates by docking high-energy intermediates to enzyme structures. J Am Chem Soc 2007; 128:15882-91. [PMID: 17147401 DOI: 10.1021/ja065860f] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
With the emergence of sequences and even structures for proteins of unknown function, structure-based prediction of enzyme activity has become a pragmatic as well as an interesting question. Here we investigate a method to predict substrates for enzymes of known structure by docking high-energy intermediate forms of the potential substrates. A database of such high-energy transition-state analogues was created from the KEGG metabolites. To reduce the number of possible reactions to consider, we restricted ourselves to enzymes of the amidohydrolase superfamily. We docked each metabolite into seven different amidohydrolases in both the ground-state and the high-energy intermediate forms. Docking the high-energy intermediates improved the discrimination between decoys and substrates significantly over the corresponding standard ground-state database, both by enrichment of the true substrates and by geometric fidelity. To test this method prospectively, we attempted to predict the enantioselectivity of a set of chiral substrates for phosphotriesterase, for both wild-type and mutant forms of this enzyme. The stereoselectivity ratios of the six enzymes considered for those four substrate enantiomer pairs differed over a range of 10- to 10,000-fold and underwent 20 switches in stereoselectivities for favored enantiomers, compared to the wild type. The docking of the high-energy intermediates correctly predicted the stereoselectivities for 18 of the 20 substrate/enzyme combinations when compared to subsequent experimental synthesis and testing. The possible applications of this approach to other enzymes are considered.
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Affiliation(s)
- Johannes C Hermann
- Department of Pharmaceutical Chemistry, University of California, San Francisco, MC 2550, San Francisco, California 94158-2330, USA
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Abstract
Phosphotriesterase (PTE) is a binuclear zinc enzyme that catalyzes the hydrolysis of extremely toxic organophosphate triesters. In the present work, we have investigated the reaction mechanism of PTE using the hybrid density functional theory method B3LYP. We present a potential energy surface for the reaction and provide characterization of the transition states and intermediates. We used the high resolution crystal structure to construct a model of the active site of PTE, containing the two zinc ions and their first shell ligands. The calculations provide strong support to an associative mechanism for the hydrolysis of phosphotriesters by PTE. No protonation of the leaving group was found to be necessary. In particular, the calculations demonstrate that the nucleophilicity of the bridging hydroxide is sufficient to be utilized in the hydrolysis reaction, a feature that is of importance for a number of other di-zinc enzymes.
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Afriat L, Roodveldt C, Manco G, Tawfik DS. The Latent Promiscuity of Newly Identified Microbial Lactonases Is Linked to a Recently Diverged Phosphotriesterase†. Biochemistry 2006; 45:13677-86. [PMID: 17105187 DOI: 10.1021/bi061268r] [Citation(s) in RCA: 206] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In essence, evolutionary processes occur gradually, while maintaining fitness throughout. Along this line, it has been proposed that the ability of a progenitor to promiscuously catalyze a low level of the evolving activity could facilitate the divergence of a new function by providing an immediate selective advantage. To directly establish a role for promiscuity in the divergence of natural enzymes, we attempted to trace the origins of a bacterial phosphotriesterase (PTE), an enzyme thought to have evolved for the purpose of degradation of a synthetic insecticide introduced in the 20th century. We surmised that PTE's promiscuous lactonase activity may be a vestige of its progenitor and tested homologues annotated as "putative PTEs" for lactonase and phosphotriesterase activity. We identified three genes that define a new group of microbial lactonases dubbed PTE-like lactonases (PLLs). These enzymes proficiently hydrolyze various lactones, and in particular quorum-sensing N-acyl homoserine lactones (AHLs), and exhibit much lower promiscuous phosphotriesterase activities. PLLs share key sequence and active site features with PTE and differ primarily by an insertion in one surface loop. Given their biochemical and biological function, PLLs are likely to have existed for many millions of years. PTE could have therefore evolved from a member of the PLL family while utilizing its latent promiscuous paraoxonase activity as an essential starting point.
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Affiliation(s)
- Livnat Afriat
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
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41
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Affiliation(s)
- Alan Peterkofsky
- Laboratory of Cell Biology, National Heart, Lung and Blood Institute, Bethesda, MD 20892-8017, USA.
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42
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Blum MM, Löhr F, Richardt A, Rüterjans H, Chen JCH. Binding of a Designed Substrate Analogue to Diisopropyl Fluorophosphatase: Implications for the Phosphotriesterase Mechanism. J Am Chem Soc 2006; 128:12750-7. [PMID: 17002369 DOI: 10.1021/ja061887n] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A wide range of organophosphorus nerve agents, including Soman, Sarin, and Tabun is efficiently hydrolyzed by the phosphotriesterase enzyme diisopropyl fluorophosphatase (DFPase) from Loligo vulgaris. To date, the lack of available inhibitors of DFPase has limited studies on its mechanism. The de novo design, synthesis, and characterization of substrate analogues acting as competitive inhibitors of DFPase are reported. The 1.73 A crystal structure of O,O-dicyclopentylphosphoroamidate (DcPPA) bound to DFPase shows a direct coordination of the phosphoryl oxygen by the catalytic calcium ion. The binding mode of this substrate analogue suggests a crucial role for electrostatics in the orientation of the ligand in the active site. This interpretation is further supported by the crystal structures of double mutants D229N/N120D and D229N/N175D, designed to reorient the electrostatic environment around the catalytic calcium. The structures show no differences in their calcium coordinating environment, although they are enzymatically inactive. Additional double mutants E21Q/N120D and E21Q/N175D are also inactive. On the basis of these crystal structures and kinetic and mutagenesis data as well as isotope labeling we propose a new mechanism for DFPase activity. Calcium coordinating residue D229, in concert with direct substrate activation by the metal ion, renders the phosphorus atom of the substrate susceptible for attack of water, through generation of a phosphoenzyme intermediate. Our proposed mechanism may be applicable to the structurally related enzyme paraoxonase (PON), a component of high-density lipoprotein (HDL).
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Affiliation(s)
- Marc-Michael Blum
- Institute of Biophysical Chemistry, J.W. Goethe University Frankfurt, Max-von-Laue-Strasse 9, D-60438 Frankfurt, Germany
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Srinivas R, Jayalakshmi SK, Sreeramulu K, Sherman NE, Rao J. Purification and characterization of an esterase isozyme involved in hydrolysis of organophosphorus compounds from an insecticide resistant pest, Helicoverpa armigera (Lepidoptera: Noctüidae). Biochim Biophys Acta Gen Subj 2006; 1760:310-7. [PMID: 16466860 DOI: 10.1016/j.bbagen.2005.12.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2005] [Revised: 12/08/2005] [Accepted: 12/12/2005] [Indexed: 11/18/2022]
Abstract
An esterase isozyme was purified from the insecticide resistant pest, Helicoverpa armigera collected from field crops. Purification involved ammonium sulfate precipitation, hydrophobic interaction and ion exchange chromatography followed by gel filtration chromatography. The purification was 212-fold with 1% yield of the enzyme. The optimum pH of the isozyme was found to be 10.5 and 8.5 for p-nitrophenyl phosphate and paraoxon, respectively. The enzyme was unstable at temperature >50 degrees C. The molecular mass determined by SDS-PAGE was 66 kDa. Cations such as Hg(+2), Ag(+2), Cd(+2) inhibited the activity while Zn(+2) stimulated it. Kinetic studies indicated that the enzyme had low K(m) values of 0.238 and 0.348 mM for p-nitrophenyl phosphate and paraoxon, respectively. The enzyme had broad substrate specificity with high K(m) values for ATP, ADP and beta-glycerophosphate. This enzyme was partially sequenced and identified as an alkaline phosphatase.
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Affiliation(s)
- R Srinivas
- Department of Biochemistry, Gulbarga University, Gulbarga-585 106, India
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44
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Abstract
The amidohydrolase superfamily comprises hundreds of hydrolytic enzymes of the (beta/alpha)8 barrel fold with mono- or binuclear active-site metal centers, and a diverse spectrum of substrates and reactions. Promiscuous activities, or cross-reactivities, between different members of the same superfamily may provide important hints regarding evolutionary and mechanistic relationships. We examined three members: dihydroorotase (DHO), phosphotriesterase (PTE), and PTE-homology protein (PHP). Of particular interest are PTE, which is thought to have evolved within the last several decades, and PHP, an amidohydrolase superfamily member of unknown function, and the closest known homologue of PTE. We found a diverse and partially overlapping pattern of promiscuous activities in these enzymes, including a significant lactonase activity in PTE, esterase activities in both PTE and PHP, and a weak PTE activity in DHO. Directed evolution was applied to improve the promiscuous esterase activities of PTE and PHP. Remarkably, the most recurrent mutation increasing esterase activity in PTE, or PHP, maps to the same location in their superposed 3D structures. The evolved variants also exhibit newly acquired promiscuous activities that were not selected for, including very weak, yet measurable, paraoxonase activity in PHP. Our results illustrate the mechanistic, structural, and evolutionary links between these enzymes, and highlight the importance of studying laboratory evolution intermediates that might resemble node intermediates along the evolutionary pathways leading to the divergence of enzyme superfamilies.
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Affiliation(s)
- Cintia Roodveldt
- Department of Biological Chemistry, The Weizmann Institute of Science, 76100 Rehovot, Israel
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Jackson C, Kim HK, Carr PD, Liu JW, Ollis DL. The structure of an enzyme-product complex reveals the critical role of a terminal hydroxide nucleophile in the bacterial phosphotriesterase mechanism. Biochim Biophys Acta 2005; 1752:56-64. [PMID: 16054447 DOI: 10.1016/j.bbapap.2005.06.008] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2005] [Revised: 06/08/2005] [Accepted: 06/09/2005] [Indexed: 11/26/2022]
Abstract
A detailed understanding of the catalytic mechanism of enzymes is an important step toward improving their activity for use in biotechnology. In this paper, crystal soaking experiments and X-ray crystallography were used to analyse the mechanism of the Agrobacterium radiobacter phosphotriesterase, OpdA, an enzyme capable of detoxifying a broad range of organophosphate pesticides. The structures of OpdA complexed with ethylene glycol and the product of dimethoate hydrolysis, dimethyl thiophosphate, provide new details of the catalytic mechanism. These structures suggest that the attacking nucleophile is a terminally bound hydroxide, consistent with the catalytic mechanism of other binuclear metallophosphoesterases. In addition, a crystal structure with the potential substrate trimethyl phosphate bound non-productively demonstrates the importance of the active site cavity in orienting the substrate into an approximation of the transition state.
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Affiliation(s)
- Colin Jackson
- Research School of Chemistry, Australian National University, Canberra ACT 0200, Australia
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46
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Ghanem E, Raushel FM. Detoxification of organophosphate nerve agents by bacterial phosphotriesterase. Toxicol Appl Pharmacol 2005; 207:459-70. [PMID: 15982683 DOI: 10.1016/j.taap.2005.02.025] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2004] [Revised: 02/01/2005] [Accepted: 02/15/2005] [Indexed: 11/25/2022]
Abstract
Organophosphates have been widely used as insecticides and chemical warfare agents. The health risks associated with these agents have necessitated the need for better detoxification and bioremediation tools. Bacterial enzymes capable of hydrolyzing the lethal organophosphate nerve agents are of special interest. Phosphotriesterase (PTE) isolated from the soil bacteria Pseudomonas diminuta displays a significant rate enhancement and substrate promiscuity for the hydrolysis of organophosphate triesters. Directed evolution and rational redesign of the active site of PTE have led to the identification of new variants with enhanced catalytic efficiency and stereoselectivity toward the hydrolysis of organophosphate neurotoxins. PTE has been utilized to protect against organophosphate poisoning in vivo. Biotechnological applications of PTE for detection and decontamination of insecticides and chemical warfare agents are developing into useful tools. In this review, the catalytic properties and potential applications of this remarkable enzyme are discussed.
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Affiliation(s)
- Eman Ghanem
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, TX 77843-3012, USA
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47
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Katsemi V, Lücke C, Koepke J, Löhr F, Maurer S, Fritzsch G, Rüterjans H. Mutational and structural studies of the diisopropylfluorophosphatase from Loligo vulgaris shed new light on the catalytic mechanism of the enzyme. Biochemistry 2005; 44:9022-33. [PMID: 15966726 DOI: 10.1021/bi0500675] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The active site, the substrate binding site, and the metal binding sites of the diisopropylfluorophosphatase (DFPase) from Loligo vulgaris have been modified by means of site-directed mutagenesis to improve our understanding of the reaction mechanism. Enzymatic characterization of mutants located in the major groove of the substrate binding pocket indicates that large hydrophobic side chains at these positions are favorable for substrate turnover. Moreover, the active site residue His287 proved to be beneficial, but not essential, for DFP hydrolysis. In most cases, hydrophobic side chains at position 287 led to significant catalytic activities although reduced relative to the wild-type enzyme. With respect to the Ca-1 binding site, where catalysis occurs, various mutants indicated that the net charge at this calcium-binding site as well as the relative positions of the charged calcium ligands is crucial for catalytic activity. The importance of the electrostatic potential at the active site was furthermore revealed by various mutations of residues lining the interior of the central water-filled tunnel, which traverses the entire protein structure. In this respect, the structural features of residue His181, which is located at the opposite end of the DFPase tunnel relative to the active site, were characterized extensively. It was concluded that a tunnel-spanning hydrogen bond network, which includes a large number of apparently slow exchanging water molecules, relays any modifications in the electrostatics of the system to the active site, thus affecting the catalytic reactivity of the enzyme.
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Affiliation(s)
- Vicky Katsemi
- Institute of Biophysical Chemistry, Center for Biomolecular Magnetic Resonance, J. W. Goethe University of Frankfurt, Germany
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48
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Abstract
Phosphotriesterase (PTE) is a binuclear metalloenzyme that catalyzes the hydrolysis of organophosphates, including pesticides and chemical warfare agents, at rates approaching the diffusion controlled limit. The catalytic mechanism of this enzyme features a bridging solvent molecule that is proposed to initiate nucleophilic attack at the phosphorus center of the substrate. X-band EPR spectroscopy is utilized to investigate the active site of Mn/Mn-substituted PTE. Simulation of the dominant EPR spectrum from the coupled binuclear center of Mn/Mn-PTE requires slightly rhombic zero-field splitting parameters. Assuming that the signal arises from the S = 2 manifold, an exchange coupling constant of J = -2.7 +/- 0.2 cm(-)(1) (H(ex) = -2JS(1) x S(2)) is calculated. A kinetic pK(a) of 7.1 +/- 0.1 associated with loss in activity at low pH indicates that a protonation event is responsible for inhibition of catalysis. Analysis of changes in the EPR spectrum as a function of pH provides a pK(a) of 7.3 +/- 0.1 that is assigned as the protonation of the hydroxyl bridge. From the comparison of kinetic and spectral pK(a) values, it is concluded that the loss of catalytic activity at acidic pH results from the protonation of the hydroxide that bridges the binuclear metal center.
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Affiliation(s)
- Cynthia R Samples
- Department of Chemistry, P.O. Box 30012, Texas A&M University, College Station, Texas 77842-3012, USA
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McLoughlin SY, Jackson C, Liu JW, Ollis D. Increased expression of a bacterial phosphotriesterase in Escherichia coli through directed evolution. Protein Expr Purif 2005; 41:433-40. [PMID: 15866732 DOI: 10.1016/j.pep.2005.01.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2005] [Revised: 01/03/2005] [Indexed: 11/18/2022]
Abstract
We devised a growth-based strategy for screening phosphotriesterase mutant libraries for variants with enhanced activity towards organophosphates that generate dimethyl phosphate when hydrolysed. Phosphotriesterase mutants were screened for activity by growing transformed Escherichia coli on agar plates containing methyl paraoxon as a sole phosphorus source. E. coli is capable of growth under these conditions when coexpressing the phosphotriesterase from Agrobacterium radiobacter P230 (OpdA) and the glycerophosphodiester phosphodiesterase from Enterobacter aerogenes (GpdQ). The latter enzyme can hydrolyse the dimethyl phosphate produced by the phosphotriesterase to methyl phosphate, which can then be used by E. coli as a source of phosphate. Phosphotriesterase was expressed from the lac promoter at levels such that its activity was growth-rate limiting. Cultures of the largest colonies (1% of the transformants) were assayed for activity towards paraoxon spectrophotometrically in microtitre plates. This process produced E. coli variants with higher whole cell activity than wild-type, which was found to be a consequence of increased protein expression rather than any increase in enzymatic activity. The mutations present in these mutant enzymes with increased expression were exclusively in the coding region, suggesting the improvement occurs post-transcriptionally.
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Affiliation(s)
- Sean Yu McLoughlin
- Research School of Chemistry, Building 35 Science Road, Australian National University, Canberra ACT 0200, Australia
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Merone L, Mandrich L, Rossi M, Manco G. A thermostable phosphotriesterase from the archaeon Sulfolobus solfataricus: cloning, overexpression and properties. Extremophiles 2005; 9:297-305. [PMID: 15909078 DOI: 10.1007/s00792-005-0445-4] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2004] [Accepted: 02/28/2005] [Indexed: 10/25/2022]
Abstract
A new gene from the hyperthermophilic archaeon Sulfolobus solfataricus MT4, coding for a putative protein reported to show sequence identity with the phosphotriesterase-related protein family (PHP), was cloned by means of the polymerase chain reaction from the S. solfataricus genomic DNA. In order to analyse the biochemical properties of the protein an overexpression system in Escherichia coli was established. The recombinant protein, expressed in soluble form at 5 mg/l of E. coli culture, was purified to homogeneity and characterized. In contrast with its mesophilic E. coli counterpart that was devoid of any tested activity, the S. solfataricus enzyme was demonstrated to have a low paraoxonase activity. This activity was dependent from metal cations with Co(2+), Mg(2+) and Ni(2+) being the most effective and was thermophilic and thermostable. The enzyme was inactivated with EDTA and o-phenantroline. A reported inhibitor for Pseudomonas putida phosphotriesterase (PTE) had no effect on the S. solfataricus paraoxonase. The importance of a stable paraoxonase for detoxification of chemical warfare agents and agricultural pesticides will be discussed.
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Affiliation(s)
- Luigia Merone
- Istituto di Biochimica delle Proteine, Consiglio Nazionale delle Ricerche, Via P. Castellino, Napoli, Italy
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