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Wang Y, Deng C, Wang X. Characterization of a novel salt- and solvent-tolerant esterase Dhs82 from soil metagenome capable of hydrolyzing estrogenic phthalate esters. Biophys Chem 2025; 316:107348. [PMID: 39531866 DOI: 10.1016/j.bpc.2024.107348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2024] [Revised: 10/19/2024] [Accepted: 11/04/2024] [Indexed: 11/16/2024]
Abstract
Esterases that can function under extreme conditions are important for industrial processing and environmental remediation. Here, we report the identification of a salt- and solvent-tolerant esterase, Dhs82, from a soil metagenomic library. Dhs82 prefers short-chain p-nitrophenyl (p-NP) esters and exhibits enzymatic activity up to 1460 ± 61 U/mg towards p-NP butyrate. Meanwhile, Dhs82 can catalyze the hydrolysis of dialkyl phthalate esters, especially the widely-used diethyl phthalate (DEP), dipropyl phthalate (DPP) and di-n-butyl phthalate (DBP). Importantly, as an acidic protein with negative charges dominating its surface, Dhs82 is highly active and extraordinarily stable at high salinity. This property is quite rare among previously reported esterases/hydrolases capable of degrading phthalate esters (PAEs). In addition, Dhs82 activity can be significantly enhanced in the presence of solvents over a concentration range of 10-30 % (v/v). Notably, Dhs82 also showed high stability towards these solvents and solvent concentrations as high as 50-60 % (v/v) are required to inactivate Dhs82. Furthermore, molecular docking revealed the key residues, including the catalytic triad (Ser156, His281, and Asp251) and the surrounding Gly84 and Gly85, involved in the interaction of Dhs82 with DBP, depicting how Dhs82 degrades PAEs as a family IV esterase. Together, these diverse properties make Dhs82 a valuable candidate for both basic research and biotechnological applications.
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Affiliation(s)
- Yuanyan Wang
- School of Science, China Pharmaceutical University, Nanjing 211198, PR China
| | - Chunmei Deng
- School of Science, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 211198, PR China
| | - Xin Wang
- School of Science, China Pharmaceutical University, Nanjing 211198, PR China.
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2
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Qiao P, Ying T, Gu M, Zhu J, Mei C, Hu T, Liu T, Wang H, Zhong W. Assimilation of phthalate esters in bacteria. Appl Microbiol Biotechnol 2024; 108:276. [PMID: 38536521 PMCID: PMC10973024 DOI: 10.1007/s00253-024-13105-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Revised: 02/29/2024] [Accepted: 03/06/2024] [Indexed: 05/29/2025]
Abstract
The massive usage of phthalate esters (PAEs) has caused serious pollution. Bacterial degradation is a potential strategy to remove PAE contamination. So far, an increasing number of PAE-degrading strains have been isolated, and the catabolism of PAEs has been extensively studied and reviewed. However, the investigation into the bacterial PAE uptake process has received limited attention and remains preliminary. PAEs can interact spontaneously with compounds like peptidoglycan, lipopolysaccharides, and lipids on the bacterial cell envelope to migrate inside. However, this process compromises the structural integrity of the cells and causes disruptions. Thus, membrane protein-facilitated transport seems to be the main assimilation strategy in bacteria. So far, only an ATP-binding-cassette transporter PatDABC was proven to transport PAEs across the cytomembrane in a Gram-positive bacterium Rhodococcus jostii RHA1. Other cytomembrane proteins like major facilitator superfamily (MFS) proteins and outer membrane proteins in cell walls like FadL family channels, TonB-dependent transporters, and OmpW family proteins were only reported to facilitate the transport of PAEs analogs such as monoaromatic and polyaromatic hydrocarbons. The functions of these proteins in the intracellular transport of PAEs in bacteria await characterization and it is a promising avenue for future research on enhancing bacterial degradation of PAEs. KEY POINTS: • Membrane proteins on the bacterial cell envelope may be PAE transporters. • Most potential transporters need experimental validation.
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Affiliation(s)
- Pei Qiao
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Tongtong Ying
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Mengjie Gu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Jiahong Zhu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Chengyu Mei
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Tong Hu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Tengfei Liu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Haixia Wang
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Weihong Zhong
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China.
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3
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Liu YY, Zhang YX, Wen HM, Liu XL, Fan XJ. Cloning and rational modification of a cold-adapted esterase for phthalate esters and parabens degradation. CHEMOSPHERE 2023; 325:138393. [PMID: 36925017 DOI: 10.1016/j.chemosphere.2023.138393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 02/01/2023] [Accepted: 03/11/2023] [Indexed: 06/18/2023]
Abstract
Phthalate esters (PAEs) and parabens are environmental pollutants that can be toxic to human health. Herein, a cold-adapted esterase from the Mao-tofu metagenome named Est1260 was screened for its PAE-hydrolyzing potential in cold temperatures. The results showed that purified Est1260 could degrade a variety of PAEs and parabens at temperatures as low as 0 °C. After careful analysis of the structural information and molecular docking, site-saturation mutation was conducted at the identified hotspots. Protein expression of variant A1B6 doubled, and its thermal stability significantly improved (24 times) without sacrificing activity at low temperatures. In addition, Est1260 and its variants were activated by NaCl and demonstrated resistance to high concentrations of saline (up to 5 M), making it a potential biocatalyst for bioremediation of PAE and paraben-polluted environments.
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Affiliation(s)
- Yan-Yan Liu
- School of Basic Medical Sciences, Anhui Medical University, 81 Meishan Rd, Hefei, 230032, Anhui, People's Republic of China; Clinical Laboratory of Suzhou First People's Hospital, People's Republic of China
| | - Yi-Xin Zhang
- School of Basic Medical Sciences, Anhui Medical University, 81 Meishan Rd, Hefei, 230032, Anhui, People's Republic of China
| | - Hua-Mei Wen
- School of Basic Medical Sciences, Anhui Medical University, 81 Meishan Rd, Hefei, 230032, Anhui, People's Republic of China
| | - Xiao-Long Liu
- School of Basic Medical Sciences, Anhui Medical University, 81 Meishan Rd, Hefei, 230032, Anhui, People's Republic of China; University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
| | - Xin-Jiong Fan
- School of Basic Medical Sciences, Anhui Medical University, 81 Meishan Rd, Hefei, 230032, Anhui, People's Republic of China.
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Kikani B, Patel R, Thumar J, Bhatt H, Rathore DS, Koladiya GA, Singh SP. Solvent tolerant enzymes in extremophiles: Adaptations and applications. Int J Biol Macromol 2023; 238:124051. [PMID: 36933597 DOI: 10.1016/j.ijbiomac.2023.124051] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 03/05/2023] [Accepted: 03/12/2023] [Indexed: 03/18/2023]
Abstract
Non-aqueous enzymology has always drawn attention due to the wide range of unique possibilities in biocatalysis. In general, the enzymes do not or insignificantly catalyze substrate in the presence of solvents. This is due to the interfering interactions of the solvents between enzyme and water molecules at the interface. Therefore, information about solvent-stable enzymes is scarce. Yet, solvent-stable enzymes prove quite valuable in the present day biotechnology. The enzymatic hydrolysis of the substrates in solvents synthesizes commercially valuable products, such as peptides, esters, and other transesterification products. Extremophiles, the most valuable yet not extensively explored candidates, can be an excellent source to investigate this avenue. Due to inherent structural attributes, many extremozymes can catalyze and maintain stability in organic solvents. In the present review, we aim to consolidate information about the solvent-stable enzymes from various extremophilic microorganisms. Further, it would be interesting to learn about the mechanism adapted by these microorganisms to sustain solvent stress. Various approaches to protein engineering are used to enhance catalytic flexibility and stability and broaden biocatalysis's prospects under non-aqueous conditions. It also describes strategies to achieve optimal immobilization with minimum inhibition of the catalysis. The proposed review would significantly aid our understanding of non-aqueous enzymology.
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Affiliation(s)
- Bhavtosh Kikani
- Department of Biosciences, Saurashtra University, Rajkot 360 005, Gujarat, India; Department of Biological Sciences, P.D. Patel Institute of Applied Sciences, Charotar University of Science and Technology, Changa 388 421, Gujarat, India
| | - Rajesh Patel
- Department of Biosciences, Veer Narmad South Gujarat University, Surat 395 007, Gujarat, India
| | - Jignasha Thumar
- Government Science College, Gandhinagar 382 016, Gujarat, India
| | - Hitarth Bhatt
- Department of Biosciences, Saurashtra University, Rajkot 360 005, Gujarat, India; Department of Microbiology, Faculty of Science, Atmiya University, Rajkot 360005, Gujarat, India
| | - Dalip Singh Rathore
- Department of Biosciences, Saurashtra University, Rajkot 360 005, Gujarat, India; Gujarat Biotechnology Research Centre, Gandhinagar 382 010, Gujarat, India
| | - Gopi A Koladiya
- Department of Biosciences, Saurashtra University, Rajkot 360 005, Gujarat, India
| | - Satya P Singh
- Department of Biosciences, Saurashtra University, Rajkot 360 005, Gujarat, India.
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Lai J, Huang H, Lin M, Xu Y, Li X, Sun B. Enzyme catalyzes ester bond synthesis and hydrolysis: The key step for sustainable usage of plastics. Front Microbiol 2023; 13:1113705. [PMID: 36713200 PMCID: PMC9878459 DOI: 10.3389/fmicb.2022.1113705] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 12/29/2022] [Indexed: 01/15/2023] Open
Abstract
Petro-plastic wastes cause serious environmental contamination that require effective solutions. Developing alternatives to petro-plastics and exploring feasible degrading methods are two solving routes. Bio-plastics like polyhydroxyalkanoates (PHAs), polylactic acid (PLA), polycaprolactone (PCL), poly (butylene succinate) (PBS), poly (ethylene furanoate) s (PEFs) and poly (ethylene succinate) (PES) have emerged as promising alternatives. Meanwhile, biodegradation plays important roles in recycling plastics (e.g., bio-plastics PHAs, PLA, PCL, PBS, PEFs and PES) and petro-plastics poly (ethylene terephthalate) (PET) and plasticizers in plastics (e.g., phthalate esters, PAEs). All these bio- and petro-materials show structure similarity by connecting monomers through ester bond. Thus, this review focused on bio-plastics and summarized the sequences and structures of the microbial enzymes catalyzing ester-bond synthesis. Most of these synthetic enzymes belonged to α/β-hydrolases with conserved serine catalytic active site and catalyzed the polymerization of monomers by forming ester bond. For enzymatic plastic degradation, enzymes about PHAs, PBS, PCL, PEFs, PES and PET were discussed, and most of the enzymes also belonged to the α/β hydrolases with a catalytic active residue serine, and nucleophilically attacked the ester bond of substrate to generate the cleavage of plastic backbone. Enzymes hydrolysis of the representative plasticizer PAEs were divided into three types (I, II, and III). Type I enzymes hydrolyzed only one ester-bond of PAEs, type II enzymes catalyzed the ester-bond of mono-ester phthalates, and type III enzymes hydrolyzed di-ester bonds of PAEs. Divergences of catalytic mechanisms among these enzymes were still unclear. This review provided references for producing bio-plastics, and degrading or recycling of bio- and petro-plastics from an enzymatic point of view.
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Affiliation(s)
- Jinghui Lai
- Key Laboratory of Brewing Microbiology and Enzymatic Molecular Engineering of China General Chamber of Commence, Beijing Technology and Business University, Beijing, China
| | - Huiqin Huang
- Key Laboratory of Brewing Microbiology and Enzymatic Molecular Engineering of China General Chamber of Commence, Beijing Technology and Business University, Beijing, China
| | - Mengwei Lin
- Key Laboratory of Brewing Microbiology and Enzymatic Molecular Engineering of China General Chamber of Commence, Beijing Technology and Business University, Beijing, China
| | - Youqiang Xu
- Key Laboratory of Brewing Microbiology and Enzymatic Molecular Engineering of China General Chamber of Commence, Beijing Technology and Business University, Beijing, China
| | - Xiuting Li
- Key Laboratory of Brewing Microbiology and Enzymatic Molecular Engineering of China General Chamber of Commence, Beijing Technology and Business University, Beijing, China
- Key Laboratory of Brewing Molecular Engineering of China Light Industry, Beijing Technology and Business University, Beijing, China
| | - Baoguo Sun
- Key Laboratory of Brewing Microbiology and Enzymatic Molecular Engineering of China General Chamber of Commence, Beijing Technology and Business University, Beijing, China
- Key Laboratory of Brewing Molecular Engineering of China Light Industry, Beijing Technology and Business University, Beijing, China
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Fan X, Gu C, Jin Z, Cai J, Bian Y, Wang F, Chen H, Jiang X. Major biotransformation of phthalic acid esters in Eisenia fetida: Mechanistic insights and association with catalytic enzymes and intestinal symbionts. ENVIRONMENT INTERNATIONAL 2023; 171:107712. [PMID: 36577298 DOI: 10.1016/j.envint.2022.107712] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 11/22/2022] [Accepted: 12/20/2022] [Indexed: 06/17/2023]
Abstract
Phthalic acid esters (PAEs) are an important group of organic pollutants that are widely used as plasticizers in the environment. The PAEs in soil organisms are likely to be biotransformed into a variety of metabolites, and the combined toxicity of PAEs and their metabolites might be more serious than PAEs alone. However, there are only a few studies on PAE biotransformation by terrestrial animals, e.g. earthworms. Herein, the key biotransformation pathways of PAEs and their association with catalytic enzymes and intestinal symbionts in earthworms were studied using in vivo and in vitro incubation approaches. The widely distributed PAE in soil, dibutyl phthalate (DBP), was proven to be biotransformed rapidly together with apparent bioaccumulation in earthworms. The biotransformation of PAE congeners with medium or long side chains appeared to be faster compared with those with short side chains. DBP was biotransformed into butyl methyl phthalate (BMP), monobutyl phthalate (MBP), and phthalic acid (PA) through esterolysis and transesterification. Besides, the generation of small quantities of low-molecular weight metabolites via β-oxidation, decarboxylation or ring-cleavage, was also observed, especially when the appropriate proportion of NADPH coenzyme was applied to transfer electrons for oxidases. Interestingly, the esterolysis of PAEs was mainly regulated by the cytoplasmic carboxylesterase (CarE) in earthworms, with a Michaelis constant (Km) of 0.416 mM in the catalysis of DBP. The stronger esterolysis in non-intestinal tissues indicated that the CarE was primarily secreted by non-intestinal tissues of earthworms. Additionally, the intestinal symbiotic bacteria of earthworms could respond to PAE stress, leading to the changes in their diversity and composition. The enrichment of some genera e.g. Bacillus and Paracoccus, and the enhancement of metabolism function, e.g. amino acids, energy, lipids biosynthesis and oxidase secretion, indicated their important role in the degradation of PAEs.
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Affiliation(s)
- Xiuli Fan
- CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China; University of the Chinese Academy of Sciences, Beijing 100049, PR China
| | - Chenggang Gu
- CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China; University of the Chinese Academy of Sciences, Beijing 100049, PR China.
| | - Zhihua Jin
- CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China; University of the Chinese Academy of Sciences, Beijing 100049, PR China
| | - Jun Cai
- CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China; University of the Chinese Academy of Sciences, Beijing 100049, PR China
| | - Yongrong Bian
- CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China; University of the Chinese Academy of Sciences, Beijing 100049, PR China
| | - Fang Wang
- CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China; University of the Chinese Academy of Sciences, Beijing 100049, PR China
| | - Hong Chen
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China
| | - Xin Jiang
- CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China; University of the Chinese Academy of Sciences, Beijing 100049, PR China
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7
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Different Effects of Salt Bridges near the Active Site of Cold-Adapted Proteus mirabilis Lipase on Thermal and Organic Solvent Stabilities. Catalysts 2022. [DOI: 10.3390/catal12070761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Organic solvent-tolerant (OST) enzymes have been discovered in psychrophiles. Cold-adapted OST enzymes exhibit increased conformational flexibility in polar organic solvents resulting from their intrinsically flexible structures. Proteus mirabilis lipase (PML), a cold-adapted OST lipase, was used to assess the contribution of salt bridges near the active site involving two arginine residues (R237 and R241) on the helix η1 and an aspartate residue (D248) on the connecting loop to the thermal and organic solvent stabilities of PML. Alanine substitutions for the ion pairs (R237A, R241A, D248A, and R237A/D248A) increased the conformational flexibility of PML mutants compared to that of the wild-type PML in an aqueous buffer. The PML mutants became more susceptible to denaturation after increasing the dimethyl sulfoxide or methanol concentration than after a temperature increase. Methanol was more detrimental to the structural stability of PML compared to dimethyl sulfoxide. These results suggest that direct interactions of dimethyl sulfoxide and methanol with the residues near the active site can have a destructive effect on the structure of PML compared with the global effect of heat on the protein structure. This study provides insight into the conformational changes within an OST enzyme with different effects on its thermal and organic solvent stabilities.
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Bhattacharyya M, Basu S, Dhar R, Dutta TK. Phthalate hydrolase: distribution, diversity and molecular evolution. ENVIRONMENTAL MICROBIOLOGY REPORTS 2022; 14:333-346. [PMID: 34816599 DOI: 10.1111/1758-2229.13028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 11/08/2021] [Accepted: 11/09/2021] [Indexed: 05/12/2023]
Abstract
The alpha/beta-fold superfamily of hydrolases is rapidly becoming one of the largest groups of structurally related enzymes with diverse catalytic functions. In this superfamily of enzymes, esterase deserves special attention because of their wide distribution in biological systems and importance towards environmental and industrial applications. Among various esterases, phthalate hydrolases are the key alpha/beta enzymes involved in the metabolism of structurally diverse estrogenic phthalic acid esters, ubiquitously distributed synthetic chemicals, used as plasticizer in plastic manufacturing processes. Although they vary both at the sequence and functional levels, these hydrolases use a similar acid-base-nucleophile catalytic mechanism to catalyse reactions on structurally different substrates. The current review attempts to present insights on phthalate hydrolases, describing their sources, structural diversities, phylogenetic affiliations and catalytically different types or classes of enzymes, categorized as diesterase, monoesterase and diesterase-monoesterase, capable of hydrolysing phthalate diester, phthalate monoester and both respectively. Furthermore, available information on in silico analyses and site-directed mutagenesis studies revealing structure-function integrity and altered enzyme kinetics have been highlighted along with the possible scenario of their evolution at the molecular level.
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Affiliation(s)
| | - Suman Basu
- Department of Microbiology, Bose Institute, Kolkata, West Bengal, India
| | - Rinita Dhar
- Department of Microbiology, Bose Institute, Kolkata, West Bengal, India
| | - Tapan K Dutta
- Department of Microbiology, Bose Institute, Kolkata, West Bengal, India
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Phthalate Esters Metabolic Strain Gordonia sp. GZ-YC7, a Potential Soil Degrader for High Concentration Di-(2-ethylhexyl) Phthalate. Microorganisms 2022; 10:microorganisms10030641. [PMID: 35336217 PMCID: PMC8955600 DOI: 10.3390/microorganisms10030641] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 03/12/2022] [Accepted: 03/15/2022] [Indexed: 02/01/2023] Open
Abstract
As commonly used chemical plasticizers in plastic products, phthalate esters have become a serious ubiquitous environmental pollutant, such as in soil of plastic film mulch culture. Microbial degradation or transformation was regarded as a suitable strategy to solve the phthalate esters pollution. Thus, a new phthalate esters degrading strain Gordonia sp. GZ-YC7 was isolated in this study, which exhibited the highest di-(2-ethylhexyl) phthalate degradation efficiency under 1000 mg/L and the strongest tolerance to 4000 mg/L. The comparative genomic analysis results showed that there exist diverse esterases for various phthalate esters such as di-(2-ethylhexyl) phthalate and dibutyl phthalate in Gordonia sp. GZ-YC7. This genome characteristic possibly contributes to its broad substrate spectrum, high degrading efficiency, and high tolerance to phthalate esters. Gordonia sp. GZ-YC7 has potential for the bioremediation of phthalate esters in polluted soil environments.
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Vingiani GM, Leone S, De Luca D, Borra M, Dobson ADW, Ianora A, De Luca P, Lauritano C. First identification and characterization of detoxifying plastic-degrading DBP hydrolases in the marine diatom Cylindrotheca closterium. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 812:152535. [PMID: 34942245 DOI: 10.1016/j.scitotenv.2021.152535] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 12/14/2021] [Accepted: 12/15/2021] [Indexed: 06/14/2023]
Abstract
Diatoms are photosynthetic organisms with potential biotechnological applications in the bioremediation sector, having shown the capacity to reduce environmental concentrations of different pollutants. The diatom Cylindrotheca closterium is known to degrade di-n-butyl phthalate (DBP), one of the most abundant phthalate esters in aquatic environments and a known endocrine-disrupting chemical. In this study, we present for the first time the in silico identification of two putative DBP hydrolases (provisionally called DBPH1 and DBPH2) in the transcriptome of C. closterium. We modeled the structure of both DBPH1-2 and their proposed interactions with the substrate to gain insights into their mechanism of action. Finally, we analyzed the expression levels of the two putative hydrolases upon exposure of C. closterium to different concentrations of DBP (5 and 10 mg/l) for 24 and 48 h. The data showed a DBP concentration-dependent increase in expression levels of both dbph1 and 2 genes, further highlighting their potential involvement in phthalates degradation. This is the first identification of phthalate-degrading enzymes in microalgae, providing new insights into the possible use of diatoms in bioremediation strategies targeting phthalates.
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Affiliation(s)
- Giorgio Maria Vingiani
- Ecosustainable Marine Biotechnology Department, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli, Italy
| | - Serena Leone
- Department of Biology and Evolution of Marine Organisms (BEOM), Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli, Italy
| | - Daniele De Luca
- Department of Biology, University of Naples Federico II, Botanic Garden of Naples, Via Foria 223, 80139 Naples, Italy
| | - Marco Borra
- Research Infrastructure for Marine Biological Resources Department, Stazione Zoologica Anton Dohrn, Villa Comunale, CAP80121, NA, Italy
| | - Alan D W Dobson
- School of Microbiology, University College Cork, College Road, T12 YN60 Cork, Ireland; Environmental Research Institute, University College Cork, Lee Road, T23XE10 Cork, Ireland
| | - Adrianna Ianora
- Ecosustainable Marine Biotechnology Department, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli, Italy
| | - Pasquale De Luca
- Research Infrastructure for Marine Biological Resources Department, Stazione Zoologica Anton Dohrn, Villa Comunale, CAP80121, NA, Italy
| | - Chiara Lauritano
- Ecosustainable Marine Biotechnology Department, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli, Italy.
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González-Pleiter M, Velázquez D, Casero MC, Tytgat B, Verleyen E, Leganés F, Rosal R, Quesada A, Fernández-Piñas F. Microbial colonizers of microplastics in an Arctic freshwater lake. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 795:148640. [PMID: 34246139 DOI: 10.1016/j.scitotenv.2021.148640] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 06/03/2021] [Accepted: 06/20/2021] [Indexed: 05/12/2023]
Abstract
Microplastics (MPs) have been found everywhere as they are easily transported between environmental compartments. Through their transport, MPs are quickly colonized by microorganisms; this microbial community is known as the plastisphere. Here, we characterized the plastisphere of three MPs, one biodegradable (PHB) and two non-biodegradables (HDPE and LDPE), deployed in an Arctic freshwater lake for eleven days. The plastisphere was found to be complex, confirming that about a third of microbial colonizers were viable. Plastisphere was compared to microbial communities on the surrounding water and microbial mats on rocks at the bottom of the lake. Microbial mats followed by MPs showed the highest diversity regarding both prokaryotes and eukaryotes as compared to water samples; however, for fungi, MPs showed the highest diversity of the tested substrates. Significant differences on microbial assemblages on the three tested substrates were found; regarding microbial assemblages on MPs, bacterial genera found in polar environments such as Mycoplana, Erythromicrobium and Rhodoferax with species able to metabolize recalcitrant chemicals were abundant. Eukaryotic communities on MPs were characterized by the presence of ciliates of the genera Stentor, Vorticella and Uroleptus and the algae Cryptomonas, Chlamydomonas, Tetraselmis and Epipyxis. These ciliates normally feed on algae so that the complexity of these assemblages may serve to unravel trophic relationships between co-existing taxa. Regarding fungal communities on MPs, the most abundant genera were Betamyces, Cryptococcus, Arrhenia and Paranamyces. MPs, particularly HDPE, were enriched in the sulI and ermB antibiotic resistance genes (ARGs) which may raise concerns about human health-related issues as ARGs may be transferred horizontally between bacteria. This study highlights the importance of proper waste management and clean-up protocols to protect the environmental health of pristine environments such as polar regions in a context of global dissemination of MPs which may co-transport microorganisms, some of them including ARGs.
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Affiliation(s)
- Miguel González-Pleiter
- Departamento de Biología, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid, Spain
| | - David Velázquez
- Departamento de Biología, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid, Spain
| | - María Cristina Casero
- Departamento de Biogeoquímica y Ecología Microbiana, Museo Nacional de Ciencias Naturales, CSIC, E-28006 Madrid, Spain
| | - Bjorn Tytgat
- Laboratory of Protistology & Aquatic Ecology, Ghent University, Krijgslaan 281-S8, 9000 Gent, Belgium
| | - Elie Verleyen
- Laboratory of Protistology & Aquatic Ecology, Ghent University, Krijgslaan 281-S8, 9000 Gent, Belgium
| | - Francisco Leganés
- Departamento de Biología, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid, Spain
| | - Roberto Rosal
- Department of Chemical Engineering, University of Alcalá, E-28871 Alcalá de Henares, Madrid, Spain
| | - Antonio Quesada
- Departamento de Biología, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid, Spain
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12
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Yan Z, Ding L, Zou D, Qiu J, Shao Y, Sun S, Li L, Xin Z. Characterization of a novel carboxylesterase with catalytic activity toward di(2-ethylhexyl) phthalate from a soil metagenomic library. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 785:147260. [PMID: 33957585 DOI: 10.1016/j.scitotenv.2021.147260] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 04/16/2021] [Accepted: 04/16/2021] [Indexed: 06/12/2023]
Abstract
A novel carboxylesterase gene estyz5 was isolated from a soil metagenomic library. The recombinant enzyme EstYZ5 is 298 amino acids in length with a predicted molecular weight of 32 kDa. Sequence alignment and phylogenetic analysis revealed that EstYZ5 belongs to the hormone-sensitive lipase (HSL) family with a deduced catalytic triad of Ser144-Glu238-His268. EstYZ5 contains two conserved motifs, a pentapeptide motif GDSAG and a HGGG motif, which are typically found in members of the HSL family. Esterolytic activity of the recombinant enzyme was optimal at 30 °C and pH 8.0, and the kcat/Km value of the enzyme for the optimum substrate p-nitrophenyl butyrate was as high as 1272 mM-1·s-1. Importantly, EstYZ5 showed activity toward di(2-ethylhexyl) phthalate with complex side chains, which is rare for HSLs. Molecular docking simulations revealed that the catalytic triad and an oxyanion hole likely play vital roles in enzymatic activity and specificity. The phthalate-degrading activity of EstYZ5, combined with its high levels of esterolytic activity, render this new enzyme a candidate for biotechnological applications.
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Affiliation(s)
- Zhenzhen Yan
- Key Laboratory of Food Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Liping Ding
- Key Laboratory of Food Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Dandan Zou
- Key Laboratory of Food Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Jiarong Qiu
- Key Laboratory of Food Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Yuting Shao
- Key Laboratory of Food Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Shengwei Sun
- Key Laboratory of Food Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Longxiang Li
- Key Laboratory of Food Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Zhihong Xin
- Key Laboratory of Food Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China.
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13
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Integrated Multi-omics Investigations Reveal the Key Role of Synergistic Microbial Networks in Removing Plasticizer Di-(2-Ethylhexyl) Phthalate from Estuarine Sediments. mSystems 2021; 6:e0035821. [PMID: 34100638 PMCID: PMC8269228 DOI: 10.1128/msystems.00358-21] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Di-(2-ethylhexyl) phthalate (DEHP) is the most widely used plasticizer worldwide, with an annual global production of more than 8 million tons. Because of its improper disposal, endocrine-disrupting DEHP often accumulates in estuarine sediments in industrialized countries at submillimolar levels, resulting in adverse effects on both ecosystems and human beings. The microbial degraders and biodegradation pathways of DEHP in O2-limited estuarine sediments remain elusive. Here, we employed an integrated meta-omics approach to identify the DEHP degradation pathway and major degraders in this ecosystem. Estuarine sediments were treated with DEHP or its derived metabolites, o-phthalic acid and benzoic acid. The rate of DEHP degradation in denitrifying mesocosms was two times slower than that of o-phthalic acid, suggesting that side chain hydrolysis of DEHP is the rate-limiting step of anaerobic DEHP degradation. On the basis of microbial community structures, functional gene expression, and metabolite profile analysis, we proposed that DEHP biodegradation in estuarine sediments is mainly achieved through synergistic networks between denitrifying proteobacteria. Acidovorax and Sedimenticola are the major degraders of DEHP side chains; the resulting o-phthalic acid is mainly degraded by Aestuariibacter through the UbiD-dependent benzoyl coenzyme A (benzoyl-CoA) pathway. We isolated and characterized Acidovorax sp. strain 210-6 and its extracellular hydrolase, which hydrolyzes both alkyl side chains of DEHP. Interestingly, genes encoding DEHP/mono-(2-ethylhexyl) phthalate (MEHP) hydrolase and phthaloyl-CoA decarboxylase—key enzymes for side chain hydrolysis and o-phthalic acid degradation, respectively—are flanked by transposases in these proteobacterial genomes, indicating that DEHP degradation capacity is likely transferred horizontally in microbial communities. IMPORTANCE Xenobiotic phthalate esters (PAEs) have been produced on a considerably large scale for only 70 years. The occurrence of endocrine-disrupting di-(2-ethylhexyl) phthalate (DEHP) in environments has raised public concern, and estuarine sediments are major DEHP reservoirs. Our multi-omics analyses indicated that complete DEHP degradation in O2-limited estuarine sediments depends on synergistic microbial networks between diverse denitrifying proteobacteria and uncultured candidates. Our data also suggested that the side chain hydrolysis of DEHP, rather than o-phthalic acid activation, is the rate-limiting step in DEHP biodegradation within O2-limited estuarine sediments. Therefore, deciphering the bacterial ecophysiology and related biochemical mechanisms can help facilitate the practice of bioremediation in O2-limited environments. Furthermore, the DEHP hydrolase genes of active DEHP degraders can be used as molecular markers to monitor environmental DEHP degradation. Finally, future studies on the directed evolution of identified DEHP/mono-(2-ethylhexyl) phthalate (MEHP) hydrolase would bring a more catalytically efficient DEHP/MEHP hydrolase into practice.
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14
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An integrated overview of bacterial carboxylesterase: Structure, function and biocatalytic applications. Colloids Surf B Biointerfaces 2021; 205:111882. [PMID: 34087776 DOI: 10.1016/j.colsurfb.2021.111882] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 05/21/2021] [Accepted: 05/24/2021] [Indexed: 12/19/2022]
Abstract
Carboxylesterases (CEs) are members of prominent esterase, and as their name imply, they catalyze the cleavage of ester linkages. By far, a considerable number of novel CEs have been identified to investigate their exquisite physiological and biochemical properties. They are abundant enzymes in nature, widely distributed in relatively broad temperature range and in various sources; both macroorganisms and microorganisms. Given the importance of these enzymes in broad industries, interest in the study of their mechanisms and structural-based engineering are greatly increasing. This review presents the current state of knowledge and understanding about the structure and functions of this ester-metabolizing enzyme, primarily from bacterial sources. In addition, the potential biotechnological applications of bacterial CEs are also encompassed. This review will be useful in understanding the molecular basis and structural protein of bacterial CEs that are significant for the advancement of enzymology field in industries.
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15
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Das MT, Kumar SS, Ghosh P, Shah G, Malyan SK, Bajar S, Thakur IS, Singh L. Remediation strategies for mitigation of phthalate pollution: Challenges and future perspectives. JOURNAL OF HAZARDOUS MATERIALS 2021; 409:124496. [PMID: 33187797 DOI: 10.1016/j.jhazmat.2020.124496] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 10/15/2020] [Accepted: 11/04/2020] [Indexed: 05/12/2023]
Abstract
Phthalates are a group of emerging xenobiotic compounds commonly used as plasticizers. In recent times, there has been an increasing concern over the risk of phthalate exposure leading to adverse effects to human health and the environment. Therefore, it is necessary to not only understand the current status of phthalate pollution, their sources, exposure routes and health impacts, but also identify remediation technologies for mitigating phthalate pollution. Present review article aims to inform its readers about the ever increasing data on health burdens posed by phthalates and simultaneously highlights the recent advancements in research to alleviate phthalate contamination from environment. The article enumerates the major phthalates in use today, traces their environmental fate, addresses their growing health hazard concerns and largely focus on to provide an in-depth understanding of the different physical, chemical and biological treatment methods currently being used or under research for alleviating the risk of phthalate pollution, their challenges and the future research perspectives.
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Affiliation(s)
- Mihir Tanay Das
- Department of Environmental Science, Fakir Mohan University, Balasore 756020, Odisha, India
| | - Smita S Kumar
- J.C. Bose University of Science and Technology, YMCA, Faridabad 121006, Haryana, India; Centre for Rural Development and Technology, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Pooja Ghosh
- Centre for Rural Development and Technology, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Goldy Shah
- Centre for Rural Development and Technology, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Sandeep K Malyan
- Institute for Soil, Water, and Environmental Sciences, The Volcani Center, Agricultural Research Organization (ARO), Rishon LeZion 7505101, Israel
| | - Somvir Bajar
- J.C. Bose University of Science and Technology, YMCA, Faridabad 121006, Haryana, India
| | - Indu Shekhar Thakur
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110 067, India
| | - Lakhveer Singh
- Department of Environmental Science, SRM University-AP, Amaravati 522502, Andhra Pradesh, India.
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16
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VuThi H, Jang SH, Lee C. Cloning and characterization of a thermostable glutathione reductase from a psychrophilic Arctic bacterium Sphingomonas sp. FEMS Microbiol Lett 2020; 366:5593954. [PMID: 31626298 DOI: 10.1093/femsle/fnz218] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Accepted: 10/16/2019] [Indexed: 11/13/2022] Open
Abstract
Glutathione reductase is an important oxidoreductase that helps maintain redox homeostasis by catalyzing the conversion of glutathione disulfide to glutathione using NADPH as a cofactor. In this study, we cloned and characterized a glutathione reductase (hereafter referred to as SpGR) from Sphingomonas sp. PAMC 26621, an Arctic bacterium. SpGR comprises 449 amino acids, and functions as a dimer. Surprisingly, SpGR exhibits characteristics of thermophilic enzymes, showing optimum activity at 60°C and thermal stability up to 70°C with ∼50% residual activity at 70°C for 2 h. The amino acid composition analysis of SpGR showed a 1.9-fold higher Arg content (6%) and a 2.7-fold lower Lys/Arg ratio (0.75) compared to the Arg content (3.15%) and the Lys/Arg ratio (2.01) of known psychrophilic glutathione reductases. SpGR also exhibits its activity at 4°C, and circular dichroism and fluorescence spectroscopy results indicate that SpGR maintains its secondary and tertiary structures within the temperature range of 4-70°C. Taken together, the results of this study indicate that despite its origin from a psychrophilic bacterium, SpGR has high thermal stability. Our study provides an insight into the role of glutathione reductase in maintaining the reducing power of an Arctic bacterium in a broad range of temperatures.
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Affiliation(s)
- Hai VuThi
- Department of Biomedical Science and Center for Bio-Nanomaterials, Daegu University, Gyeongsan 38453, South Korea
| | - Sei-Heon Jang
- Department of Biomedical Science and Center for Bio-Nanomaterials, Daegu University, Gyeongsan 38453, South Korea
| | - ChangWoo Lee
- Department of Biomedical Science and Center for Bio-Nanomaterials, Daegu University, Gyeongsan 38453, South Korea
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Sarkar J, Dutta A, Pal Chowdhury P, Chakraborty J, Dutta TK. Characterization of a novel family VIII esterase EstM2 from soil metagenome capable of hydrolyzing estrogenic phthalates. Microb Cell Fact 2020; 19:77. [PMID: 32209105 PMCID: PMC7092541 DOI: 10.1186/s12934-020-01336-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 03/18/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Microbes are rich sources of enzymes and esterases are one of the most important classes of enzymes because of their potential for application in the field of food, agriculture, pharmaceuticals and bioremediation. Due to limitations in their cultivation, only a small fraction of the complex microbial communities can be cultured from natural habitats. Thus to explore the catalytic potential of uncultured organisms, the metagenomic approach has turned out to be an effective alternative method for direct mining of enzymes of interest. Based on activity-based screening method, an esterase-positive clone was obtained from metagenomic libraries. RESULTS Functional screening of a soil metagenomic fosmid library, followed by transposon mutagenesis led to the identification of a 1179 bp esterase gene, estM2, that encodes a 392 amino acids long protein (EstM2) with a translated molecular weight of 43.12 kDa. Overproduction, purification and biochemical characterization of the recombinant protein demonstrated carboxylesterase activity towards short-chain fatty acyl esters with optimal activity for p-nitrophenyl butyrate at pH 8.0 and 37 °C. Amino acid sequence analysis and subsequent phylogenetic analysis suggested that EstM2 belongs to the family VIII esterases that bear modest similarities to class C β-lactamases. EstM2 possessed the conserved S-x-x-K motif of class C β-lactamases but did not exhibit β-lactamase activity. Guided by molecular docking analysis, EstM2 was shown to hydrolyze a wide range of di- and monoesters of alkyl-, aryl- and benzyl-substituted phthalates. Thus, EstM2 displays an atypical hydrolytic potential of biotechnological significance within family VIII esterases. CONCLUSIONS This study has led to the discovery of a new member of family VIII esterases. To the best of our knowledge, this is the first phthalate hydrolase (EstM2), isolated from a soil metagenomic library that belongs to a family possessing β-lactamase like catalytic triad. Based on its catalytic potential towards hydrolysis of both phthalate diesters and phthalate monoesters, this enzyme may find use to counter the growing pollution caused by phthalate-based plasticizers in diverse geological environment and in other aspects of biotechnological applications.
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Affiliation(s)
- Jayita Sarkar
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VII M, Kolkata, 700054, India
| | - Arindam Dutta
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VII M, Kolkata, 700054, India
| | - Piyali Pal Chowdhury
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VII M, Kolkata, 700054, India
| | - Joydeep Chakraborty
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VII M, Kolkata, 700054, India
| | - Tapan K Dutta
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VII M, Kolkata, 700054, India.
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Fan S, Wang J, Yan Y, Wang J, Jia Y. Excellent Degradation Performance of a Versatile Phthalic Acid Esters-Degrading Bacterium and Catalytic Mechanism of Monoalkyl Phthalate Hydrolase. Int J Mol Sci 2018; 19:ijms19092803. [PMID: 30231475 PMCID: PMC6164851 DOI: 10.3390/ijms19092803] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 09/05/2018] [Accepted: 09/08/2018] [Indexed: 12/03/2022] Open
Abstract
Despites lots of characterized microorganisms that are capable of degrading phthalic acid esters (PAEs), there are few isolated strains with high activity towards PAEs under a broad range of environmental conditions. In this study, Gordonia sp. YC-JH1 had advantages over its counterparts in terms of di(2-ethylhexyl) phthalate (DEHP) degradation performance. It possessed an excellent degradation ability in the range of 20–50 °C, pH 5.0–12.0, or 0–8% NaCl with the optimal degradation condition 40 °C and pH 10.0. Therefore, strain YC-JH1 appeared suitable for bioremediation application at various conditions. Metabolites analysis revealed that DEHP was sequentially hydrolyzed by strain YC-JH1 to mono(2-ethylhexyl) phthalate (MEHP) and phthalic acid (PA). The hydrolase MphG1 from strain YC-JH1 hydrolyzed monoethyl phthalate (MEP), mono-n-butyl phthalate (MBP), mono-n-hexyl phthalate (MHP), and MEHP to PA. According to molecular docking and molecular dynamics simulation between MphG1 and monoalkyl phthalates (MAPs), some key residues were detected, including the catalytic triad (S125-H291-D259) and the residues R126 and F54 potentially binding substrates. The mutation of these residues accounted for the reduced activity. Together, the mechanism of MphG1 catalyzing MAPs was elucidated, and would shed insights into catalytic mechanism of more hydrolases.
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Affiliation(s)
- Shuanghu Fan
- Graduate School of Chinese Academy of Agricultural Sciences, Beijing 100081, China.
| | - Junhuan Wang
- Graduate School of Chinese Academy of Agricultural Sciences, Beijing 100081, China.
| | - Yanchun Yan
- Graduate School of Chinese Academy of Agricultural Sciences, Beijing 100081, China.
| | - Jiayi Wang
- Graduate School of Chinese Academy of Agricultural Sciences, Beijing 100081, China.
| | - Yang Jia
- Graduate School of Chinese Academy of Agricultural Sciences, Beijing 100081, China.
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Fan S, Wang J, Li K, Yang T, Jia Y, Zhao B, Yan Y. Complete genome sequence of Gordonia sp. YC-JH1, a bacterium efficiently degrading a wide range of phthalic acid esters. J Biotechnol 2018; 279:55-60. [DOI: 10.1016/j.jbiotec.2018.05.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 04/29/2018] [Accepted: 05/09/2018] [Indexed: 02/05/2023]
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20
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Kashif A, Tran LH, Jang SH, Lee C. Roles of Active-Site Aromatic Residues in Cold Adaptation of Sphingomonas glacialis Esterase EstSP1. ACS OMEGA 2017; 2:8760-8769. [PMID: 31457406 PMCID: PMC6645578 DOI: 10.1021/acsomega.7b01435] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 11/23/2017] [Indexed: 06/10/2023]
Abstract
The aromatic amino acids, Tyr or Trp, which line the active-site walls of esterases, stabilize the catalytic His loop via hydrogen bonding. A Tyr residue is preferred in extremophilic esterases (psychrophilic or hyperthermophilic esterases), whereas a Trp residue is preferred in moderate-temperature esterases. Here, we provide evidence that Tyr and Trp play distinct roles in cold adaptation of the psychrophilic esterase EstSP1 isolated from an Arctic bacterium Sphingomonas glacialis PAMC 26605. Stern-Volmer plots showed that the mutation of Tyr191 to Ala, Phe, Trp, and His resulted in reduced conformational flexibility of the overall protein structure. Interestingly, the Y191W and Y191H mutants showed increased thermal stability at moderate temperatures. All Tyr191 mutants showed reduced catalytic activity relative to wild-type EstSP1. Our results indicate that Tyr with its phenyl hydroxyl group is favored for increased conformational flexibility and high catalytic activity of EstSP1 at low temperatures at the expense of thermal stability. The results of this study suggest that, in the permanently cold Arctic zone, enzyme activity has been selected for psychrophilic enzymes over thermal stability. The results presented herein provide novel insight into the roles of Tyr and Trp residues for temperature adaptation of enzymes that function at low, moderate, and high temperatures.
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Affiliation(s)
| | | | | | - ChangWoo Lee
- E-mail: . Tel: +82-53-850-6464. Fax: +82-53-850-6469
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21
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Bacteria-mediated phthalic acid esters degradation and related molecular mechanisms. Appl Microbiol Biotechnol 2017; 102:1085-1096. [DOI: 10.1007/s00253-017-8687-5] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 11/30/2017] [Accepted: 11/30/2017] [Indexed: 10/18/2022]
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