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Liu D, Diao W, Chen H, Qi X, Fang H, Yu X, Li L, Bai Y, Liang C. Heterologous expression and characterization of a dye-decolorizing peroxidase from Ganoderma lucidum, and its application in decolorization and detoxifization of different types of dyes. World J Microbiol Biotechnol 2024; 40:303. [PMID: 39153119 DOI: 10.1007/s11274-024-04084-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Accepted: 07/14/2024] [Indexed: 08/19/2024]
Abstract
Dye-decolorizing peroxidases (DyPs) belong to a novel superfamily of heme peroxidases that can oxidize recalcitrant compounds. In the current study, the GlDyP2 gene from Ganoderma lucidum was heterologously expressed in Escherichia coli, and the enzymatic properties of the recombinant GlDyP2 protein were investigated. The GlDyP2 protein could oxidize not only the typical peroxidase substrate ABTS but also two lignin substrates, namely guaiacol and 2,6-dimethoxy phenol (DMP). For the ABTS substrate, the optimum pH and temperature of GlDyP2 were 4.0 and 35 °C, respectively. The pH stability and thermal stability of GlDyP2 were also measured; the results showed that GlDyP2 could function normally in the acidic environment, with a T50 value of 51 °C. Moreover, compared to untreated controls, the activity of GlDyP2 was inhibited by 1.60 mM of Mg2+, Ni2+, Mn2+, and ethanol; 0.16 mM of Cu2+, Zn2+, methanol, isopropyl alcohol, and Na2EDTA·2H2O; and 0.016 mM of Fe2+ and SDS. The kinetic constants of recombinant GlDyP2 for oxidizing ABTS, Reactive Blue 19, guaiacol, and DMP were determined; the results showed that the recombination GlDyP2 exhibited the strongest affinity and the most remarkable catalytic efficiency towards guaiacol in the selected substrates. GlDyP2 also exhibited decolorization and detoxification capabilities towards several dyes, including Reactive Blue 19, Reactive Brilliant Blue X-BR, Reactive Black 5, Methyl Orange, Trypan Blue, and Malachite Green. In conclusion, GlDyP2 has good application potential for treating dye wastewater.
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Affiliation(s)
- Dongmei Liu
- Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing, 210014, China
| | - Wentong Diao
- Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Hong Chen
- Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Xiwu Qi
- Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing, 210014, China
| | - Hailing Fang
- Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing, 210014, China
| | - Xu Yu
- Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing, 210014, China
| | - Li Li
- Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing, 210014, China
| | - Yang Bai
- Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing, 210014, China
| | - Chengyuan Liang
- Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing, 210014, China.
- Nanjing University of Chinese Medicine, Nanjing, 210023, China.
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2
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Perez AV, Gaitan-Oyola JA, Vargas-Delgadillo DP, Castillo JJ, Barbosa O, Fernandez-Lafuente R. Synthesis and Characterization of Cross-Linked Aggregates of Peroxidase from Megathyrsus maximus (Guinea Grass) and Their Application for Indigo Carmine Decolorization. Molecules 2024; 29:2696. [PMID: 38893568 PMCID: PMC11173754 DOI: 10.3390/molecules29112696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 05/16/2024] [Accepted: 05/31/2024] [Indexed: 06/21/2024] Open
Abstract
We present the synthesis of a cross-linking enzyme aggregate (CLEAS) of a peroxidase from Megathyrsus maximus (Guinea Grass) (GGP). The biocatalyst was produced using 50%v/v ethanol and 0.88%w/v glutaraldehyde for 1 h under stirring. The immobilization yield was 93.74% and the specific activity was 36.75 U mg-1. The biocatalyst surpassed by 61% the free enzyme activity at the optimal pH value (pH 6 for both preparations), becoming this increase in activity almost 10-fold at pH 9. GGP-CLEAS exhibited a higher thermal stability (2-4 folds) and was more stable towards hydrogen peroxide than the free enzyme (2-3 folds). GGP-CLEAS removes over 80% of 0.05 mM indigo carmine at pH 5, in the presence of 0.55 mM H2O2 after 60 min of reaction, a much higher value than when using the free enzyme. The operational stability showed a decrease of enzyme activity (over 60% in 4 cycles), very likely related to suicide inhibition.
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Affiliation(s)
- Angie V. Perez
- Grupo de Investigación en Materiales Porosos con Aplicaciones Ambientales y Tecnológicas, Departamento de Química, Universidad del Tolima, Ibagué 730006299, Colombia; (A.V.P.); (J.A.G.-O.); (D.P.V.-D.)
| | - Jorge A. Gaitan-Oyola
- Grupo de Investigación en Materiales Porosos con Aplicaciones Ambientales y Tecnológicas, Departamento de Química, Universidad del Tolima, Ibagué 730006299, Colombia; (A.V.P.); (J.A.G.-O.); (D.P.V.-D.)
| | - Diana P. Vargas-Delgadillo
- Grupo de Investigación en Materiales Porosos con Aplicaciones Ambientales y Tecnológicas, Departamento de Química, Universidad del Tolima, Ibagué 730006299, Colombia; (A.V.P.); (J.A.G.-O.); (D.P.V.-D.)
| | - John J. Castillo
- Grupo de Investigación en Bioquímica y Microbiología, Escuela de Química, Universidad Industrial de Santander, Bucaramanga 680002, Colombia;
| | - Oveimar Barbosa
- Grupo de Investigación en Materiales Porosos con Aplicaciones Ambientales y Tecnológicas, Departamento de Química, Universidad del Tolima, Ibagué 730006299, Colombia; (A.V.P.); (J.A.G.-O.); (D.P.V.-D.)
| | - Roberto Fernandez-Lafuente
- Departamento de Biocatálisis, ICP-CSIC, Campus Cantoblanco UAM-CSIC, C/Marie Curie 2, 28049 Madrid, Spain
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3
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Hermann E, Rodrigues CF, Martins LO, Peterbauer C, Oostenbrink C. Engineering A-type Dye-Decolorizing Peroxidases by Modification of a Conserved Glutamate Residue. Chembiochem 2024; 25:e202300872. [PMID: 38376941 DOI: 10.1002/cbic.202300872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 02/08/2024] [Accepted: 02/20/2024] [Indexed: 02/21/2024]
Abstract
Dye-decolorizing peroxidases (DyPs) are recently identified microbial enzymes that have been used in several Biotechnology applications from wastewater treatment to lignin valorization. However, their properties and mechanism of action still have many open questions. Their heme-containing active site is buried by three conserved flexible loops with a putative role in modulating substrate access and enzyme catalysis. Here, we investigated the role of a conserved glutamate residue in stabilizing interactions in loop 2 of A-type DyPs. First, we did site saturation mutagenesis of this residue, replacing it with all possible amino acids in bacterial DyPs from Bacillus subtilis (BsDyP) and from Kitasatospora aureofaciens (KaDyP1), the latter being characterized here for the first time. We screened the resulting libraries of variants for activity towards ABTS and identified variants with increased catalytic efficiency. The selected variants were purified and characterized for activity and stability. We furthermore used Molecular Dynamics simulations to rationalize the increased catalytic efficiency and found that the main reason is the electron channeling becoming easier from surface-exposed tryptophans. Based on our findings, we also propose that this glutamate could work as a pH switch in the wild-type enzyme, preventing intracellular damage.
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Affiliation(s)
- Enikö Hermann
- Institute of Food Technology, Department of Food Science and Technology, University of Natural Resources and Life Sciences, Vienna, Muthgasse 11, 1190, Vienna, Austria
- Institute for Molecular Modeling and Simulation, Department of Material Science and Life Sciences, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190, Vienna, Austria
| | - Carolina F Rodrigues
- 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
| | - Clemens Peterbauer
- Institute of Food Technology, Department of Food Science and Technology, University of Natural Resources and Life Sciences, Vienna, Muthgasse 11, 1190, Vienna, Austria
| | - Chris Oostenbrink
- Institute for Molecular Modeling and Simulation, Department of Material Science and Life Sciences, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190, Vienna, Austria
- Christian Doppler Laboratory for Molecular Informatics in the Biosciences, University of Natural Resources and Life Sciences, Vienna, Austria
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4
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Duan X, Pi Q, Tang L. pH-dependent and whole-cell catalytic decolorization of dyes using recombinant dye-decolorizing peroxidase from Rhodococcus jostii. Bioprocess Biosyst Eng 2024; 47:355-366. [PMID: 38326513 DOI: 10.1007/s00449-024-02968-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Accepted: 01/15/2024] [Indexed: 02/09/2024]
Abstract
Dyes in wastewater have adverse effects on the environment and human health. Dye-decolorizing peroxidase (DyP) is a promising biocatalyst to dyes degradation, but the decolorization rates varied greatly which influencing factors and mechanisms remain to be fully disclosed. To explore an effective decolorizing approach, we have studied a DyP from Rhodococcus jostii (RhDyPB) which was overexpressed in Escherichia coli to decolorize four kinds of dyes, Reactive blue 19, Eosin Y, Indigo carmine, and Malachite green. We found the decolorization rates of the dyes by purified RhDyPB were all pH-dependent and the highest one was 94.4% of Malachite green at pH 6.0. ESI-MS analysis of intermediates in the decolorization process of Reactive blue 19 proved the degradation was due to peroxidase catalysis. Molecular docking predicated the interaction of RhDyPB with dyes, and a radical transfer reaction. In addition, we performed decolorization of dyes with whole E. coli cell with and without expressing RhDyPB. It was found that decolorization of dyes by E. coli cell was due to both cell absorption and degradation, and RhDyPB expression improved the degradation rates towards Reactive blue 19, Indigo carmine and Malachite green. The effective decolorization of Malachite green and the successful application of whole DyP-overexpressed cells in dye decolorization is conducive to the bioremediation of dye-containing wastewaters by DyPs.
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Affiliation(s)
- Xiaoyan Duan
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, No 1800 Lihu Avenue, Wuxi, 214122, Jiangsu, China
| | - Qian Pi
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, No 1800 Lihu Avenue, Wuxi, 214122, Jiangsu, China
| | - Lei Tang
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, No 1800 Lihu Avenue, Wuxi, 214122, Jiangsu, China.
- School of Biotechnology, Jiangnan University, No 1800 Lihu Avenue, Wuxi, 214122, Jiangsu, China.
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Pan Y, Zhang Z, Cun JE, Fan X, Pan Q, Gao W, Luo K, He B, Pu Y. Oxidase-like manganese oxide nanoparticles: a mechanism of organic acids/aldehydes as electron acceptors and potential application in cancer therapy. NANOSCALE 2024; 16:2860-2867. [PMID: 38231414 DOI: 10.1039/d3nr05127g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
Identifying the underlying catalytic mechanisms of synthetic nanocatalysts or nanozymes is important in directing their design and applications. Herein, we revisited the oxidation process of 4,4'-diamino-3,3',5,5'-tetramethylbiphenyl (TMB) by Mn3O4 nanoparticles and revealed that it adopted an organic acid/aldehyde-triggered catalytic mechanism at a weakly acidic or neutral pH, which is O2-independent and inhibited by the pre-addition of H2O2. Importantly, similar organic acid/aldehyde-mediated oxidation was applied to other substrates of peroxidase in the presence of nanoparticulate or commercially available MnO2 and Mn2O3 but not MnO. The selective oxidation of TMB by Mn3O4 over MnO was further supported by density functional theory calculations. Moreover, Mn3O4 nanoparticles enabled the oxidation of indole 3-acetic acid, a substrate that can generate cytotoxic singlet oxygen upon single-electron transfer oxidation, displaying potential in nanocatalytic tumor therapy. Overall, we revealed a general catalytic mechanism of manganese oxides towards the oxidation of peroxidase substrates, which could boost the design and various applications of these manganese-based nanoparticles.
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Affiliation(s)
- Yang Pan
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu, 610064, China
| | - Zhuangzhuang Zhang
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu, 610064, China
| | - Ju-E Cun
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu, 610064, China
| | - Xi Fan
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu, 610064, China
| | - Qingqing Pan
- School of Preclinical Medicine, Chengdu University, Chengdu, 610106, China
| | - Wenxia Gao
- College of Chemistry & Materials Engineering, Wenzhou University, Wenzhou, 325027, China
| | - Kui Luo
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital, Functional and Molecular Imaging Key Laboratory of Sichuan Province, Sichuan University, Chengdu, 610044, China.
| | - Bin He
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu, 610064, China
| | - Yuji Pu
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu, 610064, China
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6
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Baratto MC, Pogni R. Special Issue on Biotechnological Applications of Oxidoreductases. Int J Mol Sci 2024; 25:1758. [PMID: 38339033 PMCID: PMC10855645 DOI: 10.3390/ijms25031758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 01/23/2024] [Accepted: 01/29/2024] [Indexed: 02/12/2024] Open
Abstract
This Special Issue was launched in conjunction with the 10th edition of the OxiZymes meeting in Siena (Italy) in 2022 [...].
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Affiliation(s)
| | - Rebecca Pogni
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, 53100 Siena, Italy;
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7
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Sethupathy S, Xie R, Liang N, Shafreen RMB, Ali MY, Zhuang Z, Zhe L, Zahoor, Yong YC, Zhu D. Evaluation of a dye-decolorizing peroxidase from Comamonas serinivorans for lignin valorization potentials. Int J Biol Macromol 2023; 253:127117. [PMID: 37774822 DOI: 10.1016/j.ijbiomac.2023.127117] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 09/17/2023] [Accepted: 09/26/2023] [Indexed: 10/01/2023]
Abstract
Although dye-decolourising peroxidases (DyPs) are well-known for lignin degradation, a comprehensive understanding of their mechanism remains unclear. Therefore, studying the mechanism of lignin degradation by DyPs is necessary for industrial applications and enzyme engineering. In this study, a dye-decolourising peroxidase (CsDyP) gene from C. serinivorans was heterologously expressed and studied for its lignin degradation potential. Molecular docking analysis predicted the binding of 2, 2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), veratryl alcohol (VA), 2, 6-dimethylphenol (2, 6- DMP), guaiacol (GUA), and lignin to the substrate-binding pocket of CsDyP. Evaluation of the enzymatic properties showed that CsDyP requires pH 4.0 and 30 °C for optimal activity and has a high affinity for ABTS. In addition, CsDyP is stable over a wide range of temperatures and pH and can tolerate 5.0 mM organic solvents. Low NaCl concentrations promoted CsDyP activity. Further, CsDyP significantly reduced the chemical oxygen demand decolourised alkali lignin (AL) and milled wood lignin (MWL). CsDyP targets the β-O-4, CO, and CC bonds linking lignin's G, S, and H units to depolymerize and produce aromatic compounds. Overall, this study delivers valuable insights into the lignin degradation mechanism of CsDyP, which can benefit its industrial applications and lignin valorization.
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Affiliation(s)
- Sivasamy Sethupathy
- Biofuels Institute, School of Emergency Management, School of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Rongrong Xie
- Biofuels Institute, School of Emergency Management, School of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Nian Liang
- Biofuels Institute, School of Emergency Management, School of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Raja Mohamed Beema Shafreen
- Department of Biotechnology, Dr. Umayal Ramanathan College for Women, Algappapuram, Karaikudi 630003, Tamil Nadu, India
| | - Mohamed Yassin Ali
- Biofuels Institute, School of Emergency Management, School of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China; Biochemistry Department, Faculty of Agriculture, Fayoum University, Fayoum 63514, Egypt
| | - Zhipeng Zhuang
- Biofuels Institute, School of Emergency Management, School of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Liang Zhe
- Biofuels Institute, School of Emergency Management, School of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Zahoor
- Biofuels Institute, School of Emergency Management, School of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Yang-Chun Yong
- Biofuels Institute, School of Emergency Management, School of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Daochen Zhu
- Biofuels Institute, School of Emergency Management, School of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China.
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Kalkan Ö, Kantamneni S, Brings L, Han H, Bean R, Mancuso AP, Koua FHM. Heterologous expression, purification and structural features of native Dictyostelium discoideum dye-decolorizing peroxidase bound to a natively incorporated heme. Front Chem 2023; 11:1220543. [PMID: 37593106 PMCID: PMC10427876 DOI: 10.3389/fchem.2023.1220543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 07/20/2023] [Indexed: 08/19/2023] Open
Abstract
The Dictyostelium discoideum dye-decolorizing peroxidase (DdDyP) is a newly discovered peroxidase, which belongs to a unique class of heme peroxidase family that lacks homology to the known members of plant peroxidase superfamily. DdDyP catalyzes the H2O2-dependent oxidation of a wide-spectrum of substrates ranging from polycyclic dyes to lignin biomass, holding promise for potential industrial and biotechnological applications. To study the molecular mechanism of DdDyP, highly pure and functional protein with a natively incorporated heme is required, however, obtaining a functional DyP-type peroxidase with a natively bound heme is challenging and often requires addition of expensive biosynthesis precursors. Alternatively, a heme in vitro reconstitution approach followed by a chromatographic purification step to remove the excess heme is often used. Here, we show that expressing the DdDyP peroxidase in ×2 YT enriched medium at low temperature (20°C), without adding heme supplement or biosynthetic precursors, allows for a correct native incorporation of heme into the apo-protein, giving rise to a stable protein with a strong Soret peak at 402 nm. Further, we crystallized and determined the native structure of DdDyP at a resolution of 1.95 Å, which verifies the correct heme binding and its geometry. The structural analysis also reveals a binding of two water molecules at the distal site of heme plane bridging the catalytic residues (Arg239 and Asp149) of the GXXDG motif to the heme-Fe(III) via hydrogen bonds. Our results provide new insights into the geometry of native DdDyP active site and its implication on DyP catalysis.
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Affiliation(s)
- Özlem Kalkan
- European XFEL GmbH, Schenefeld, Schleswig-Holstein, Germany
- Department of Molecular Biology and Genetics, Faculty of Science, Istanbul University, Istanbul, Türkiye
| | | | - Lea Brings
- European XFEL GmbH, Schenefeld, Schleswig-Holstein, Germany
| | - Huijong Han
- European XFEL GmbH, Schenefeld, Schleswig-Holstein, Germany
| | - Richard Bean
- European XFEL GmbH, Schenefeld, Schleswig-Holstein, Germany
| | - Adrian P. Mancuso
- European XFEL GmbH, Schenefeld, Schleswig-Holstein, Germany
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
- Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot, United Kingdom
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9
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Li YY, Long SS, Yu L, Liu AK, Gao SQ, Tan X, Lin YW. Effects of naturally occurring S47F/A mutations on the structure and function of human cytochrome c. J Inorg Biochem 2023; 246:112296. [PMID: 37356378 DOI: 10.1016/j.jinorgbio.2023.112296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 06/14/2023] [Accepted: 06/16/2023] [Indexed: 06/27/2023]
Abstract
The sequence and structure of human cytochrome c (hCyt c) exhibit evolutionary conservations, with only a limited number of naturally occurring mutations in humans. Herein, we investigated the effects of the naturally occurring S47F/A mutations on the structure and function of hCyt c in the oxidized form. Although the naturally occurring S47F/A mutations did not largely alter the protein structure, the S47F and S47A variants exhibited a small fraction of high-spin species. Kinetic studies showed that the peroxidase activity of the variants was enhanced by ∼2.5-fold under neutral pH conditions, as well as for the rate in reaction with H2O2, when compared to those of wild-type hCyt c. In addition, we evaluated the interaction between hCyt c and human neuroglobin (hNgb) by isothermal titration calorimetry (ITC) studies, which revealed that the binding constant was reduced by ∼8-fold as result of the mutation of the hydrophilic Ser to the hydrophobic Phe/Ala. These findings provide valuable insights into the role of Ser47 in Ω-loop C in sustaining the structure and function of hCyt c.
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Affiliation(s)
- Yan-Yan Li
- School of Chemistry and Chemical Engineering, University of South China, Hengyang 421001, China
| | - Shuang-Shuang Long
- School of Chemistry and Chemical Engineering, University of South China, Hengyang 421001, China.
| | - Lu Yu
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Ao-Kun Liu
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Shu-Qin Gao
- Key Lab of Protein Structure and Function of Universities in Hunan Province, University of South China, Hengyang 421001, China
| | - Xiangshi Tan
- Department of Chemistry & Institute of Biomedical Science, Fudan University, Shanghai 200433, China
| | - Ying-Wu Lin
- School of Chemistry and Chemical Engineering, University of South China, Hengyang 421001, China; Key Lab of Protein Structure and Function of Universities in Hunan Province, University of South China, Hengyang 421001, China.
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