1
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Borges PT, Silva D, Silva TF, Brissos V, Cañellas M, Lucas MF, Masgrau L, Melo EP, Machuqueiro M, Frazão C, Martins LO. Unveiling molecular details behind improved activity at neutral to alkaline pH of an engineered DyP-type peroxidase. Comput Struct Biotechnol J 2022; 20:3899-3910. [PMID: 35950185 PMCID: PMC9334217 DOI: 10.1016/j.csbj.2022.07.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 07/18/2022] [Accepted: 07/18/2022] [Indexed: 01/21/2023] Open
Abstract
DyP-type peroxidases (DyPs) are microbial enzymes that catalyze the oxidation of a wide range of substrates, including synthetic dyes, lignin-derived compounds, and metals, such as Mn2+ and Fe2+, and have enormous biotechnological potential in biorefineries. However, many questions on the molecular basis of enzyme function and stability remain unanswered. In this work, high-resolution structures of PpDyP wild-type and two engineered variants (6E10 and 29E4) generated by directed evolution were obtained. The X-ray crystal structures revealed the typical ferredoxin-like folds, with three heme access pathways, two tunnels, and one cavity, limited by three long loops including catalytic residues. Variant 6E10 displays significantly increased loops' flexibility that favors function over stability: despite the considerably higher catalytic efficiency, this variant shows poorer protein stability compared to wild-type and 29E4 variants. Constant-pH MD simulations revealed a more positively charged microenvironment near the heme pocket of variant 6E10, particularly in the neutral to alkaline pH range. This microenvironment affects enzyme activity by modulating the pK a of essential residues in the heme vicinity and should account for variant 6E10 improved activity at pH 7-8 compared to the wild-type and 29E4 that show optimal enzymatic activity close to pH 4. Our findings shed light on the structure-function relationships of DyPs at the molecular level, including their pH-dependent conformational plasticity. These are essential for understanding and engineering the catalytic properties of DyPs for future biotechnological applications.
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Affiliation(s)
- Patrícia T. Borges
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Diogo Silva
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Tomás F.D. Silva
- BioISI – Biosystems & Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Vânia Brissos
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Marina Cañellas
- Zymvol Biomodeling, Carrer Roc Boronat, 117, 08018 Barcelona, Spain
| | | | - Laura Masgrau
- Zymvol Biomodeling, Carrer Roc Boronat, 117, 08018 Barcelona, Spain,Department of Chemistry, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Eduardo P. Melo
- Centro de Ciências do Mar, Universidade do Algarve, 8005-139 Faro, Portugal
| | - Miguel Machuqueiro
- BioISI – Biosystems & Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Carlos Frazão
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Lígia O. Martins
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Av. da República, 2780-157 Oeiras, Portugal,Corresponding author.
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2
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De Simone M, Alvigini L, Alonso-Cotchico L, Brissos V, Caroli J, Lucas MF, Monza E, Melo EP, Mattevi A, Martins LO. Rationally Guided Improvement of NOV1 Dioxygenase for the Conversion of Lignin-Derived Isoeugenol to Vanillin. Biochemistry 2022; 62:419-428. [PMID: 35687874 PMCID: PMC9851154 DOI: 10.1021/acs.biochem.2c00168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Biocatalysis is a key tool in both green chemistry and biorefinery fields. NOV1 is a dioxygenase that catalyzes the one-step, coenzyme-free oxidation of isoeugenol into vanillin and holds enormous biotechnological potential for the complete valorization of lignin as a sustainable starting material for biobased chemicals, polymers, and materials. This study integrates computational, kinetic, structural, and biophysical approaches to characterize a new NOV1 variant featuring improved activity and stability compared to those of the wild type. The S283F replacement results in a 2-fold increased turnover rate (kcat) for isoeugenol and a 4-fold higher catalytic efficiency (kcat/Km) for molecular oxygen compared to those of the wild type. Furthermore, the variant exhibits a half-life that is 20-fold higher than that of the wild type, which most likely relates to the enhanced stabilization of the iron cofactor in the active site. Molecular dynamics supports this view, revealing that the S283F replacement decreases the optimal pKa and favors conformations of the iron-coordinating histidines compatible with an increased level of binding to iron. Importantly, whole cells containing the S283F variant catalyze the conversion of ≤100 mM isoeugenol to vanillin, yielding >99% molar conversion yields within 24 h. This integrative strategy provided a new enzyme for biotechnological applications and mechanistic insights that will facilitate the future design of robust and efficient biocatalysts.
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Affiliation(s)
- Mario De Simone
- Instituto
de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Laura Alvigini
- Department
of Biology and Biotechnology, University
of Pavia, Via Ferrata 9, 27100 Pavia, Italy
| | | | - Vânia Brissos
- Instituto
de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Jonatan Caroli
- Department
of Biology and Biotechnology, University
of Pavia, Via Ferrata 9, 27100 Pavia, Italy
| | | | - Emanuele Monza
- Zymvol
Biomodeling SL, Carrer
Roc Boronat, 117, 08010 Barcelona, Spain
| | - Eduardo Pinho Melo
- Centro
de Ciências do Mar, Universidade
do Algarve, 8005-139 Faro, Portugal
| | - Andrea Mattevi
- Department
of Biology and Biotechnology, University
of Pavia, Via Ferrata 9, 27100 Pavia, Italy,
| | - Lígia O. Martins
- Instituto
de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Av. da República, 2780-157 Oeiras, Portugal,
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3
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Brissos V, Borges P, Núñez-Franco R, Lucas MF, Frazão C, Monza E, Masgrau L, Cordeiro TN, Martins LO. Distal Mutations Shape Substrate-Binding Sites during Evolution of a Metallo-Oxidase into a Laccase. ACS Catal 2022; 12:5022-5035. [PMID: 36567772 PMCID: PMC9775220 DOI: 10.1021/acscatal.2c00336] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Laccases are in increasing demand as innovative solutions in the biorefinery fields. Here, we combine mutagenesis with structural, kinetic, and in silico analyses to characterize the molecular features that cause the evolution of a hyperthermostable metallo-oxidase from the multicopper oxidase family into a laccase (k cat 273 s-1 for a bulky aromatic substrate). We show that six mutations scattered across the enzyme collectively modulate dynamics to improve the binding and catalysis of a bulky aromatic substrate. The replacement of residues during the early stages of evolution is a stepping stone for altering the shape and size of substrate-binding sites. Binding sites are then fine-tuned through high-order epistasis interactions by inserting distal mutations during later stages of evolution. Allosterically coupled, long-range dynamic networks favor catalytically competent conformational states that are more suitable for recognizing and stabilizing the aromatic substrate. This work provides mechanistic insight into enzymatic and evolutionary molecular mechanisms and spots the importance of iterative experimental and computational analyses to understand local-to-global changes.
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Affiliation(s)
- Vânia Brissos
- Instituto
de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av da República, 2780-157 Oeiras, Portugal
| | - Patrícia
T. Borges
- Instituto
de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av da República, 2780-157 Oeiras, Portugal
| | | | | | - Carlos Frazão
- Instituto
de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av da República, 2780-157 Oeiras, Portugal
| | - Emanuele Monza
- Zymvol
Biomodeling, Carrer Roc
Boronat, 117, 08018 Barcelona, Spain
| | - Laura Masgrau
- Zymvol
Biomodeling, Carrer Roc
Boronat, 117, 08018 Barcelona, Spain,Department
of Chemistry, Universitat Autònoma
de Barcelona, 08193 Bellaterra, Spain
| | - Tiago N. Cordeiro
- Instituto
de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av da República, 2780-157 Oeiras, Portugal
| | - Lígia O. Martins
- Instituto
de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av da República, 2780-157 Oeiras, Portugal,
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4
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Borges PT, Brissos V, Hernandez G, Masgrau L, Lucas MF, Monza E, Frazão C, Cordeiro TN, Martins LO. Methionine-Rich Loop of Multicopper Oxidase McoA Follows Open-to-Close Transitions with a Role in Enzyme Catalysis. ACS Catal 2020. [DOI: 10.1021/acscatal.0c01623] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Patrícia T. Borges
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Vânia Brissos
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Guillem Hernandez
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Laura Masgrau
- Zymvol Biomodeling, Carrer Roc Boronat, 117, 08018 Barcelona, Spain
- Department of Chemistry, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | | | - Emanuele Monza
- Zymvol Biomodeling, Carrer Roc Boronat, 117, 08018 Barcelona, Spain
| | - Carlos Frazão
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Tiago N. Cordeiro
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Lígia O. Martins
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
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5
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Valles M, Kamaruddin AF, Wong LS, Blanford CF. Inhibition in multicopper oxidases: a critical review. Catal Sci Technol 2020. [DOI: 10.1039/d0cy00724b] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
This review critiques the literature on inhibition of O2-reduction catalysis in multicopper oxidases like laccase and bilirubin oxidase and provide recommendations for best practice when carrying out experiments and interpreting published data.
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Affiliation(s)
- Morgane Valles
- Manchester Institute of Biotechnology
- University of Manchester
- Manchester
- UK
- Department of Chemistry
| | - Amirah F. Kamaruddin
- Manchester Institute of Biotechnology
- University of Manchester
- Manchester
- UK
- Department of Materials
| | - Lu Shin Wong
- Manchester Institute of Biotechnology
- University of Manchester
- Manchester
- UK
- Department of Chemistry
| | - Christopher F. Blanford
- Manchester Institute of Biotechnology
- University of Manchester
- Manchester
- UK
- Department of Materials
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6
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Abstract
Copper is a redox-active transition metal ion required for the function of many essential human proteins. For biosynthesis of proteins coordinating copper, the metal may bind before, during or after folding of the polypeptide. If the metal binds to unfolded or partially folded structures of the protein, such coordination may modulate the folding reaction. The molecular understanding of how copper is incorporated into proteins requires descriptions of chemical, thermodynamic, kinetic and structural parameters involved in the formation of protein-metal complexes. Because free copper ions are toxic, living systems have elaborate copper-transport systems that include particular proteins that facilitate efficient and specific delivery of copper ions to target proteins. Therefore, these pathways become an integral part of copper protein folding in vivo. This review summarizes biophysical-molecular in vitro work assessing the role of copper in folding and stability of copper-binding proteins as well as protein-protein copper exchange reactions between human copper transport proteins. We also describe some recent findings about the participation of copper ions and copper proteins in protein misfolding and aggregation reactions in vitro.
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7
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Brissos V, Ferreira M, Grass G, Martins LO. Turning a Hyperthermostable Metallo-Oxidase into a Laccase by Directed Evolution. ACS Catal 2015. [DOI: 10.1021/acscatal.5b00771] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Vânia Brissos
- Instituto
de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av da República, 2780-157 Oeiras, Portugal
| | - Maura Ferreira
- Instituto
de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av da República, 2780-157 Oeiras, Portugal
| | - Gregor Grass
- Bundeswehr
Institute of Microbiology, DZIF, Partner Site of German Center for Infection Research, Neuherbergstrasse 11, Munich DE 80937, Germany
| | - Lígia O. Martins
- Instituto
de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av da República, 2780-157 Oeiras, Portugal
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8
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Martins LO, Durão P, Brissos V, Lindley PF. Laccases of prokaryotic origin: enzymes at the interface of protein science and protein technology. Cell Mol Life Sci 2015; 72:911-22. [PMID: 25572294 PMCID: PMC11113980 DOI: 10.1007/s00018-014-1822-x] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 12/30/2014] [Indexed: 10/24/2022]
Abstract
The ubiquitous members of the multicopper oxidase family of enzymes oxidize a range of aromatic substrates such as polyphenols, methoxy-substituted phenols, amines and inorganic compounds, concomitantly with the reduction of molecular dioxygen to water. This family of enzymes can be broadly divided into two functional classes: metalloxidases and laccases. Several prokaryotic metalloxidases have been described in the last decade showing a robust activity towards metals, such as Cu(I), Fe(II) or Mn(II) and have been implicated in the metal metabolism of the corresponding microorganisms. Many laccases, with a superior efficiency for oxidation of organic compounds when compared with metals, have also been identified and characterized from prokaryotes, playing roles that more closely conform to those of intermediary metabolism. This review aims to present an update of current knowledge on prokaryotic multicopper oxidases, with a special emphasis on laccases, anticipating their enormous potential for industrial and environmental applications.
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Affiliation(s)
- Lígia O Martins
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2781-901, Oeiras, Portugal,
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9
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Brander S, Mikkelsen JD, Kepp KP. TtMCO: A highly thermostable laccase-like multicopper oxidase from the thermophilic Thermobaculum terrenum. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.molcatb.2014.12.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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10
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Brissos V, Gonçalves N, Melo EP, Martins LO. Improving kinetic or thermodynamic stability of an azoreductase by directed evolution. PLoS One 2014; 9:e87209. [PMID: 24475252 PMCID: PMC3903626 DOI: 10.1371/journal.pone.0087209] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Accepted: 12/20/2013] [Indexed: 12/28/2022] Open
Abstract
Protein stability arises from a combination of factors which are often difficult to rationalise. Therefore its improvement is better addressed through directed evolution than by rational design approaches. In this study, five rounds of mutagenesis/recombination followed by high-throughput screening (≈10,000 clones) yielded the hit 1B6 showing a 300-fold higher half life at 50°C than that exhibited by the homodimeric wild type PpAzoR azoreductase from Pseudomonas putida MET94. The characterization using fluorescence, calorimetry and light scattering shows that 1B6 has a folded state slightly less stable than the wild type (with lower melting and optimal temperatures) but in contrast is more resistant to irreversible denaturation. The superior kinetic stability of 1B6 variant was therefore related to an increased resistance of the unfolded monomers to aggregation through the introduction of mutations that disturbed hydrophobic patches and increased the surface net charge of the protein. Variants 2A1 and 2A1-Y179H with increased thermodynamic stability (10 to 20°C higher melting temperature than wild type) were also examined showing the distinctive nature of mutations that lead to improved structural robustness: these occur in residues that are mostly involved in strengthening the solvent-exposed loops or the inter-dimer interactions of the folded state.
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Affiliation(s)
- Vânia Brissos
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Nádia Gonçalves
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Eduardo P. Melo
- Institute for Biotechnology and Bioengineering, Center for Molecular and Structural Biomedicine, Universidade do Algarve, Faro, Portugal
| | - Lígia O. Martins
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
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11
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Rosa M, Lopes C, Melo EP, Singh SK, Geraldes V, Rodrigues MA. Measuring and Modeling Hemoglobin Aggregation below the Freezing Temperature. J Phys Chem B 2013; 117:8939-46. [DOI: 10.1021/jp4035369] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Mónica Rosa
- Centro de Química Estrutural,
Department of Chemical Engineering, Instituto Superior Técnico, Lisboa 1049-001, Portugal
| | - Carlos Lopes
- Instituto de Biotecnologia e
Bioengenharia, Centro de Biomedicina Molecular e Estrutural, Universidade do Algarve, Campus de Gambelas, 8005-139
Faro, Portugal
| | - Eduardo P. Melo
- Instituto de Biotecnologia e
Bioengenharia, Centro de Biomedicina Molecular e Estrutural, Universidade do Algarve, Campus de Gambelas, 8005-139
Faro, Portugal
| | - Satish K. Singh
- Biotherapeutics
Pharmaceutical
Sciences, Pfizer Inc., Chesterfield, Missouri
63017, United States
| | - Vitor Geraldes
- Centro de Química Estrutural,
Department of Chemical Engineering, Instituto Superior Técnico, Lisboa 1049-001, Portugal
| | - Miguel A. Rodrigues
- Centro de Química Estrutural,
Department of Chemical Engineering, Instituto Superior Técnico, Lisboa 1049-001, Portugal
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12
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New dye-decolorizing peroxidases from Bacillus subtilis and Pseudomonas putida MET94: towards biotechnological applications. Appl Microbiol Biotechnol 2013; 98:2053-65. [DOI: 10.1007/s00253-013-5041-4] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 06/04/2013] [Accepted: 06/07/2013] [Indexed: 11/27/2022]
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13
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Cartilage Acidic Protein 2 a hyperthermostable, high affinity calcium-binding protein. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:642-50. [DOI: 10.1016/j.bbapap.2012.12.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 12/14/2012] [Accepted: 12/18/2012] [Indexed: 01/27/2023]
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14
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Uthandi S, Prunetti L, De Vera IMS, Fanucci GE, Angerhofer A, Maupin-Furlow JA. Enhanced archaeal laccase production in recombinant Escherichia coli by modification of N-terminal propeptide and twin arginine translocation motifs. J Ind Microbiol Biotechnol 2012; 39:1523-32. [PMID: 22752793 DOI: 10.1007/s10295-012-1152-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Accepted: 05/28/2012] [Indexed: 11/29/2022]
Abstract
Laccases are multicopper oxidases that couple the oxidation of phenolic polymers to the reduction of molecular oxygen. While an archaeal laccase has only recently been described (LccA from the culture broth of Haloferax volcanii), this enzyme appears promising for biotechnology applications based on its robust bilirubin oxidase and laccase activities as well as its ability to withstand prolonged exposure to extreme conditions. To further optimize LccA productivity and develop an option for LccA purification from whole cells, the encoding gene was modified through deletion of the twin-arginine translocation motif and N-terminal propeptide, and the modified genes were expressed in Escherichia coli. With this approach, LccA was readily purified (overall yield up to 54 %) from the soluble fraction of E. coli as a 74-kDa monomer with syringaldazine oxidizing activity as high as 33 U mg(-1). LccA proteins prepared from H. volcanii culture broth and the soluble fraction of E. coli cells were compared by ICP-AES, EPR, DSC, CD, and UV-Vis spectroscopy and found to have a similar folding pattern with T (m) values and a rich β-sheet structure analogous to other multicopper oxidases. However, in contrast to the H. volcanii-purified LccA, which was loaded with copper, copper was not fully incorporated into the type-I Cu center of E. coli purified LccA, thus, providing insight into avenues for further optimization.
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Affiliation(s)
- Sivakumar Uthandi
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611-0700, USA.
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15
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Unfolding pathway of CotA-laccase and the role of copper on the prevention of refolding through aggregation of the unfolded state. Biochem Biophys Res Commun 2012; 422:442-6. [DOI: 10.1016/j.bbrc.2012.05.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 05/02/2012] [Indexed: 11/29/2022]
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16
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Idakieva K, Meersman F, Gielens C. Reversible heat inactivation of copper sites precedes thermal unfolding of molluscan (Rapana thomasiana) hemocyanin. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1824:731-8. [PMID: 22446410 DOI: 10.1016/j.bbapap.2012.03.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 03/05/2012] [Accepted: 03/06/2012] [Indexed: 11/16/2022]
Abstract
Hemocyanin (Hc) is a type-3 copper protein, containing dioxygen-binding active sites consisting of paired copper atoms. In the present study the thermal unfolding of the Hc from the marine mollusc Rapana thomasiana (RtH) has been investigated by combining differential scanning calorimetry, Fourier transform infrared (FTIR) and UV-vis absorption spectroscopy. Two important stages in the unfolding pathway of the Hc molecule were discerned. A first event, with nonmeasurable heat absorption, occurring around 60°C, lowers the binding of dioxygen to the type-3 copper groups. This pretransition is reversible and is ascribed to a slight change in the tertiary structure. In a second stage, with midpoint around 80°C, the protein irreversibly unfolds with a loss of secondary structure and formation of amorphous aggregates. Experiments with the monomeric structural subunits, RtH1 and RtH2, indicated that the heterogeneity in the process of thermal denaturation can be attributed to the presence of multiple 50kDa functional units with different stability. In accordance, the irreversible unfolding of a purified functional unit (RtH2-e) occurred at a single transition temperature. At slightly alkaline pH (Tris buffer) the C-terminal β-sheet rich domain of the functional unit starts to unfold before the α-helix-rich N-terminal (copper containing) domain, triggering the collapse of the global protein structure. Even around 90°C some secondary structure is preserved as shown by the FTIR spectra of all investigated samples, confirming the high thermostability of molluscan Hc.
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Affiliation(s)
- Krassimira Idakieva
- Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia, Bulgaria.
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17
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Role of metal in folding and stability of copper proteins in vitro. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1823:1594-603. [PMID: 22306006 DOI: 10.1016/j.bbamcr.2012.01.013] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 01/09/2012] [Accepted: 01/18/2012] [Indexed: 01/04/2023]
Abstract
Metal coordination is required for function of many proteins. For biosynthesis of proteins coordinating a metal, the question arises if the metal binds before, during or after folding of the polypeptide. Moreover, when the metal is bound to the protein, how does its coordination affect biophysical properties such as stability and dynamics? Understanding how metals are utilized by proteins in cells on a molecular level requires accurate descriptions of the thermodynamic and kinetic parameters involved in protein-metal complexes. Copper is one of the essential transition metals found in the active sites of many key proteins. To avoid toxicity of free copper ions, living systems have developed elaborate copper-transport systems that involve dedicated proteins that facilitate efficient and specific delivery of copper to target proteins. This review describes in vitro and in silico biophysical work assessing the role of copper in folding and stability of copper-binding proteins. Examples of proteins discussed are: a blue-copper protein (Pseudomonas aeruginosa azurin), members of copper-transport systems (bacterial CopZ, human Atox1 and ATP7B domains) and multi-copper ferroxidases (yeast Fet3p and human ceruloplasmin). The consequences of interactions between copper proteins and platinum-complexes are also discussed. This article is part of a Special Issue entitled: Cell Biology of Metals.
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18
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The removal of a disulfide bridge in CotA-laccase changes the slower motion dynamics involved in copper binding but has no effect on the thermodynamic stability. J Biol Inorg Chem 2011; 16:641-51. [DOI: 10.1007/s00775-011-0768-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Accepted: 02/08/2011] [Indexed: 10/18/2022]
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Fernandes AT, Damas JM, Todorovic S, Huber R, Baratto MC, Pogni R, Soares CM, Martins LO. The multicopper oxidase from the archaeon Pyrobaculum aerophilum shows nitrous oxide reductase activity. FEBS J 2010; 277:3176-89. [DOI: 10.1111/j.1742-4658.2010.07725.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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