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Pimviriyakul P, Buttranon S, Soithongcharoen S, Supawatkon C, Disayabootr K, Watthaisong P, Tinikul R, Jaruwat A, Chaiyen P, Chitnumsub P, Maenpuen S. Structure and biochemical characterization of an extradiol 3,4-dihydroxyphenylacetate 2,3-dioxygenase from Acinetobacter baumannii. Arch Biochem Biophys 2023; 747:109768. [PMID: 37769893 DOI: 10.1016/j.abb.2023.109768] [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: 08/24/2023] [Revised: 09/23/2023] [Accepted: 09/26/2023] [Indexed: 10/03/2023]
Abstract
3,4-Dihydroxyphenylacetate (DHPA) 2,3-dioxygenase (EC 1.13.11.15) from Acinetobacter baumannii (AbDHPAO) is an enzyme that catalyzes the 2,3-extradiol ring-cleavage of DHPA in the p-hydroxyphenylacetate (HPA) degradation pathway. While the biochemical reactions of various DHPAOs have been reported, only structures of DHPAO from Brevibacterium fuscum and their homologs are available. Here, we report the X-ray structure and biochemical characterization of an Fe2+-specific AbDHPAO that shares 12% sequence identity to the enzyme from B. fuscum. The 1.8 Å X-ray structure of apo-AbDHPAO was determined with four subunits per asymmetric unit, consistent with a homotetrameric structure. Interestingly, the αβ-sandwiched fold of the AbDHPAO subunit is different from the dual β-barrel-like motif of the well-characterized B. fuscum DHPAO structures; instead, it is similar to the structures of non-DHPA extradiol dioxygenases from Comamonas sp. and Sphingomonas paucimobilis. Similarly, these extradiol dioxygenases share the same chemistry owing to a conserved 2-His-1-carboxylate catalytic motif. Structure analysis and molecular docking suggested that the Fe2+ cofactor and substrate binding sites consist of the conserved residues His12, His57, and Glu238 forming a 2-His-1-carboxylate motif ligating to Fe2+ and DHPA bound with Fe2+ in an octahedral coordination. In addition to DHPA, AbDHPAO can also use other 3,4-dihydroxyphenylacetate derivatives with different aliphatic carboxylic acid substituents as substrates, albeit with low reactivity. Altogether, this report provides a better understanding of the structure and biochemical properties of AbDHPAO and its homologs, which is advancing further modification of DHPAO in future applications.
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Affiliation(s)
- Panu Pimviriyakul
- Department of Biochemistry, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand
| | - Supacha Buttranon
- Department of Biochemistry, Faculty of Science, Burapha University, Chonburi, 20131, Thailand; School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, 21210, Thailand
| | - Sahachat Soithongcharoen
- Department of Biochemistry, Faculty of Science, Burapha University, Chonburi, 20131, Thailand; School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, 21210, Thailand
| | - Cheerapat Supawatkon
- Department of Biochemistry, Faculty of Science, Burapha University, Chonburi, 20131, Thailand; School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, 21210, Thailand
| | - Kasidis Disayabootr
- Department of Biochemistry, Faculty of Science, Burapha University, Chonburi, 20131, Thailand
| | - Pratchaya Watthaisong
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, 21210, Thailand
| | - Ruchanok Tinikul
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Aritsara Jaruwat
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Thailand Science Park, Phahonyothin road, Khlong Nueng, Khlong Luang, Pathum Thani, 12120, Thailand
| | - Pimchai Chaiyen
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, 21210, Thailand
| | - Penchit Chitnumsub
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Thailand Science Park, Phahonyothin road, Khlong Nueng, Khlong Luang, Pathum Thani, 12120, Thailand.
| | - Somchart Maenpuen
- Department of Biochemistry, Faculty of Science, Burapha University, Chonburi, 20131, Thailand.
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Hu Y, Zhu Q, Wang Y, Liao C, Jiang G. A short review of human exposure to antibiotics based on urinary biomonitoring. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 830:154775. [PMID: 35339554 DOI: 10.1016/j.scitotenv.2022.154775] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 03/09/2022] [Accepted: 03/19/2022] [Indexed: 06/14/2023]
Abstract
Antibiotics play a role in preventing and treating infectious diseases and also contribute to other health risks for humans. With the overuse of antibiotics, they are widely distributed in the environment. Long-term exposure to multiple antibiotics may occur in humans through medication and dietary intake. Therefore, it is critical to estimate daily intake and health risk of antibiotics based on urinary biomonitoring. This review compares the strengths and weaknesses of current analytical methods to determine antibiotics in urine samples, discusses the urinary concentration profiles and hazard quotients of individual antibiotics, and overviews correlations of antibiotic exposure with the risk of diseases. Liquid chromatography-tandem mass spectrometry is most applied to simultaneously determine multiple types of antibiotics at trace levels. Solid-phase extraction with a hydrophilic-lipophilic balance adsorbent is commonly used to extract antibiotics in urine samples. Fifteen major antibiotics with relatively higher detection frequencies and concentrations include sulfaclozine, trimethoprim, erythromycin, azithromycin, penicillin V, amoxicillin, oxytetracycline, chlortetracycline, tetracycline, doxycycline, ofloxacin, enrofloxacin, ciprofloxacin, norfloxacin, and florfenicol. Humans can be easily at microbiological effect-based risk induced by florfenicol, ciprofloxacin, azithromycin, and amoxicillin. Positive associations were observed between specific antibiotic exposure and obesity, allergic diseases, and mental disorders. Overall, the accessible, automated, and environmentally friendly methods are prospected for simultaneous determinations of antibiotics at trace level in urine. To estimate human exposure to antibiotics more accurately, knowledge gaps need to be filled up, including the transformation between parent and metabolic antibiotics, urinary excretion proportions of antibiotics at low-dose exposure and pharmacokinetic data of antibiotics in humans, and the repeated sampling over a long period in future research is needed. Longitudinal studies about antibiotic exposure and the risk of diseases in different developmental windows as well as in-depth research on the pathogenic mechanism of long-term, low-dose, and joint antibiotic exposure are warranted.
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Affiliation(s)
- Yu Hu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qingqing Zhu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yawei Wang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou, Zhejiang 310024, China; Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, Hubei 430056, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chunyang Liao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou, Zhejiang 310024, China; Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, Hubei 430056, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Guibin Jiang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou, Zhejiang 310024, China; Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, Hubei 430056, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
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3
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Permsirivisarn P, Yuenyao A, Pramanpol N, Charoenwattanasatien R, Suginta W, Chaiyen P, Pakotiprapha D. Mechanism of transcription regulation by Acinetobacter baumannii HpaR in the catabolism of p-hydroxyphenylacetate. FEBS J 2021; 289:3217-3240. [PMID: 34967505 DOI: 10.1111/febs.16340] [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: 04/26/2021] [Revised: 12/16/2021] [Accepted: 12/29/2021] [Indexed: 11/25/2022]
Abstract
HpaR is a transcription regulator in the MarR family that controls the expression of the gene cluster responsible for conversion of p-hydroxyphenylacetate to pyruvate and succinate for cellular metabolism. Here, we report the biochemical and structural characterization of Acinetobacter baumannii HpaR (AbHpaR) and its complex with cognate DNA. Our study revealed that AbHpaR binds upstream of the divergently transcribed hpaA gene and the meta-cleavage operon, as well as the hpaR gene, thereby repressing their transcription by blocking access of RNA polymerase. Structural analysis of AbHpaR-DNA complex revealed that the DNA binding specificity can be achieved via a combination of both direct and indirect DNA sequence readouts. DNA binding of AbHpaR is weakened by 3,4-dihydroxyphenylacetate (DHPA), which is the substrate of the meta-cleavage reactions; this likely leads to expression of the target genes. Based on our findings, we propose a model for how A. baumannii controls transcription of HPA-metabolizing genes, which highlights the independence of global catabolite repression and could be beneficial for metabolic engineering towards bioremediation applications.
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Affiliation(s)
- Permkun Permsirivisarn
- Doctor of Philosophy Program in Biochemistry (International Program), Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.,Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.,Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Anan Yuenyao
- Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Nuttawan Pramanpol
- Synchrotron Light Research Institute (Public Organization), Nakhon Ratchasima, 30000, Thailand.,National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathum Thani, 12120, Thailand
| | | | - Wipa Suginta
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, 21210, Thailand
| | - Pimchai Chaiyen
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, 21210, Thailand
| | - Danaya Pakotiprapha
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.,Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
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Catalytic and structural insights into a stereospecific and thermostable Class II aldolase HpaI from Acinetobacter baumannii. J Biol Chem 2021; 297:101280. [PMID: 34624314 PMCID: PMC8560999 DOI: 10.1016/j.jbc.2021.101280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 10/01/2021] [Accepted: 10/01/2021] [Indexed: 11/21/2022] Open
Abstract
Aldolases catalyze the reversible reactions of aldol condensation and cleavage and have strong potential for the synthesis of chiral compounds, widely used in pharmaceuticals. Here, we investigated a new Class II metal aldolase from the p-hydroxyphenylacetate degradation pathway in Acinetobacter baumannii, 4-hydroxy-2-keto-heptane-1,7-dioate aldolase (AbHpaI), which has various properties suitable for biocatalysis, including stereoselectivity/stereospecificity, broad aldehyde utilization, thermostability, and solvent tolerance. Notably, the use of Zn2+ by AbHpaI as a native cofactor is distinct from other enzymes in this class. AbHpaI can also use other metal ion (M2+) cofactors, except Ca2+, for catalysis. We found that Zn2+ yielded the highest enzyme complex thermostability (Tm of 87 °C) and solvent tolerance. All AbHpaI•M2+ complexes demonstrated preferential cleavage of (4R)-2-keto-3-deoxy-D-galactonate ((4R)-KDGal) over (4S)-2-keto-3-deoxy-D-gluconate ((4S)-KDGlu), with AbHpaI•Zn2+ displaying the highest R/S stereoselectivity ratio (sixfold higher than other M2+ cofactors). For the aldol condensation reaction, AbHpaI•M2+ only specifically forms (4R)-KDGal and not (4S)-KDGlu and preferentially catalyzes condensation rather than cleavage by ∼40-fold. Based on 11 X-ray structures of AbHpaI complexed with M2+ and ligands at 1.85 to 2.0 Å resolution, the data clearly indicate that the M2+ cofactors form an octahedral geometry with Glu151 and Asp177, pyruvate, and water molecules. Moreover, Arg72 in the Zn2+-bound form governs the stereoselectivity/stereospecificity of AbHpaI. X-ray structures also show that Ca2+ binds at the trimer interface via interaction with Asp51. Hence, we conclude that AbHpaI•Zn2+ is distinctive from its homologues in substrate stereospecificity, preference for aldol formation over cleavage, and protein robustness, and is attractive for biocatalytic applications.
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Zhang J, Liu K, Sun L, Yang L, Liu X, Zhu Y, Wei R, Jin Z, Wang L, Ma Y, Wang S, Liu A, Tao F. Exposure to antibiotics and mental disorders in children: a community-based cross-sectional study. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2021; 43:3237-3253. [PMID: 33547614 DOI: 10.1007/s10653-021-00840-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Accepted: 01/23/2021] [Indexed: 06/12/2023]
Abstract
Although exposure to antibiotics at a critical developmental time window has been implicated in mental health in observational and experimental studies, very limited bio-monitoring data are available for exposure to antibiotics associated with child mental disorders. The goal of our study was to examine the association between urinary exposure of children to antibiotics and mental health. The participants were 278 children from 256 eligible families in the urban-rural fringe of Fuyang city in China since June in 2017. A single-point urine sample was collected to measure the antibiotic concentrations to characterize the exposure levels. A total of 45 antibiotics from nine classes and their two metabolites were monitored through liquid chromatography electrospray tandem mass spectrometry. We used multivariable regressions to estimate the covariate-adjusted associations between urine-antibiotic concentrations and mental impairments, as assessed using the parent version of Strengths and Difficulties Questionnaire. Among the participants, ciprofloxacin was associated with an increased risk of mental disorders at both lower concentrations (OR = 4.06; 95% CI 1.69-9.78) and higher concentrations OR = 6.04; 95% CI 2.59-14.08). After categorizing the detected antibiotics, the positive associations were observed between abnormal score in total difficulties and higher levels exposure to fluoroquinolones (OR = 2.83, 95% CI 1.38-5.80) and antibiotics preferred for veterinary use (PVAs) (OR = 3.20; 95% CI 1.41-7.27), respectively. Our findings suggest that ciprofloxacin, fluoroquinolones and PVAs, probably from contaminated food or environment, may be associated with child mental disorders.
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Affiliation(s)
- Jingjing Zhang
- School of Public Health, Anhui Medical University, No 81 Meishan Road, Hefei, 230032, Anhui, China
- MOE Key Laboratory of Population Health Across Life Cycle/Anhui Provincial Key Laboratory of Population Health and Aristogenics, No 81 Meishan Road, Anhui, 230032, China
| | - Kaiyong Liu
- School of Public Health, Anhui Medical University, No 81 Meishan Road, Hefei, 230032, Anhui, China.
- MOE Key Laboratory of Population Health Across Life Cycle/Anhui Provincial Key Laboratory of Population Health and Aristogenics, No 81 Meishan Road, Anhui, 230032, China.
| | - Liang Sun
- Fuyang Center of Disease Control and Prevention, Fuyang, 236000, Anhui, China
| | - Linsheng Yang
- School of Public Health, Anhui Medical University, No 81 Meishan Road, Hefei, 230032, Anhui, China
| | - Xinji Liu
- School of Public Health, Anhui Medical University, No 81 Meishan Road, Hefei, 230032, Anhui, China
| | - Yitian Zhu
- School of Public Health, Anhui Medical University, No 81 Meishan Road, Hefei, 230032, Anhui, China
| | - Rong Wei
- School of Public Health, Anhui Medical University, No 81 Meishan Road, Hefei, 230032, Anhui, China
| | - Zhongxiu Jin
- School of Public Health, Anhui Medical University, No 81 Meishan Road, Hefei, 230032, Anhui, China
| | - Li Wang
- School of Health Management, Anhui Medical University, Hefei, 230032, China
| | - Ying Ma
- School of Health Management, Anhui Medical University, Hefei, 230032, China
| | - Sufang Wang
- School of Public Health, Anhui Medical University, No 81 Meishan Road, Hefei, 230032, Anhui, China
| | - Annuo Liu
- School of Nursing, Anhui Medical University, Hefei, 230032, Anhui, China
| | - Fangbiao Tao
- School of Public Health, Anhui Medical University, No 81 Meishan Road, Hefei, 230032, Anhui, China
- MOE Key Laboratory of Population Health Across Life Cycle/Anhui Provincial Key Laboratory of Population Health and Aristogenics, No 81 Meishan Road, Anhui, 230032, China
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6
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Xu B, Xue R, Zhou J, Wen X, Shi Z, Chen M, Xin F, Zhang W, Dong W, Jiang M. Characterization of Acetamiprid Biodegradation by the Microbial Consortium ACE-3 Enriched From Contaminated Soil. Front Microbiol 2020; 11:1429. [PMID: 32733403 PMCID: PMC7360688 DOI: 10.3389/fmicb.2020.01429] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 06/02/2020] [Indexed: 12/26/2022] Open
Abstract
Microbial consortia are ubiquitous in nature and exhibit several attractive features such as sophisticated metabolic capabilities and strong environmental robustness. This study aimed to decipher the metabolic and ecological characteristics of synergistic interactions in acetamiprid-degrading consortia, suggesting an optimal scheme for bioremediation of organic pollutants. The microbial consortium ACE-3 with excellent acetamiprid-degrading ability was enriched from the soil of an acetamiprid-contaminated site and characterized using high-throughput sequencing (HTS). Consortium ACE-3 was able to completely degrade 50 mg⋅L–1 acetamiprid in 144 h, and was metabolically active at a wide range of pH values (6.0–8.0) and temperatures (20–42°C). Furthermore, plausible metabolic routes of acetamiprid biodegradation by the consortium were proposed based on the identification of intermediate metabolites (Compounds I, II, III and IV). The findings indicated that the consortium ACE-3 has promising potential for the removal and detoxification of pesticides because it produces downstream metabolites (Compounds I and II) that are less toxic to mammals and insects than acetamiprid. Finally, Illumina HTS revealed that β Proteobacteria were the dominant group, accounting for 85.61% of all sequences at the class level. Among the more than 50 genera identified in consortium ACE-3, Sphingobium, Acinetobacter, Afipia, Stenotrophomonas, and Microbacterium were dominant, respectively accounting for 3.07, 10.01, 24.45, and 49.12% of the total population.
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Affiliation(s)
- Bin Xu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Rui Xue
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Jie Zhou
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Xin Wen
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Zhoukun Shi
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Minjiao Chen
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Fengxue Xin
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China.,Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, China
| | - Wenming Zhang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China.,Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, China
| | - Weiliang Dong
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China.,Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, China
| | - Min Jiang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China.,Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, China
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7
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Kim H, Kim S, Kim D, Yoon SH. A single amino acid substitution in aromatic hydroxylase (HpaB) of Escherichia coli alters substrate specificity of the structural isomers of hydroxyphenylacetate. BMC Microbiol 2020; 20:109. [PMID: 32375644 PMCID: PMC7201708 DOI: 10.1186/s12866-020-01798-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 04/22/2020] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND A broad range of aromatic compounds can be degraded by enteric bacteria, and hydroxyphenylacetic acid (HPA) degrading bacteria are the most widespread. Majority of Escherichia coli strains can use both the structural isomers of HPA, 3HPA and 4HPA, as the sole carbon source, which are catabolized by the same pathway whose associated enzymes are encoded by hpa gene cluster. Previously, we observed that E. coli B REL606 grew only on 4HPA, while E. coli B BL21(DE3) grew on 3HPA as well as 4HPA. RESULTS In this study, we report that a single amino acid in 4-hydroxyphenylacetate 3-hydroxylase (HpaB) of E. coli determines the substrate specificity of HPA isomers. Alignment of protein sequences encoded in hpa gene clusters of BL21(DE3) and REL606 showed that there was a difference of only one amino acid (position 379 in HpaB) between the two, viz., Arg in BL21(DE3) and Cys in REL606. REL606 cells expressing HpaB having Arg379 could grow on 3HPA, whereas those expressing HpaB with Gly379 or Ser379 could not. Structural analysis suggested that the amino acid residue at position 379 of HpaB is located not in the active site, but in the vicinity of the 4HPA binding site, and that it plays an important role in mediating the entrance and stable binding of substrates to the active site. CONCLUSIONS The arginine residue at position 379 of HpaB is critical for 3HPA recognition. Information regarding the effect of amino acid residues on the substrate specificity of structural isomers can facilitate in designing hydoxylases with high catalytic efficiency and versatility.
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Affiliation(s)
- Hanseol Kim
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, 05029, Republic of Korea
| | - Sinyeon Kim
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, 05029, Republic of Korea
| | - Dohyeon Kim
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, 05029, Republic of Korea
| | - Sung Ho Yoon
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, 05029, Republic of Korea.
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8
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Chenprakhon P, Wongnate T, Chaiyen P. Monooxygenation of aromatic compounds by flavin-dependent monooxygenases. Protein Sci 2020; 28:8-29. [PMID: 30311986 DOI: 10.1002/pro.3525] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 10/08/2018] [Accepted: 10/08/2018] [Indexed: 12/12/2022]
Abstract
Many flavoenzymes catalyze hydroxylation of aromatic compounds especially phenolic compounds have been isolated and characterized. These enzymes can be classified as either single-component or two-component flavin-dependent hydroxylases (monooxygenases). The hydroxylation reactions catalyzed by the enzymes in this group are useful for modifying the biological properties of phenolic compounds. This review aims to provide an in-depth discussion of the current mechanistic understanding of representative flavin-dependent monooxygenases including 3-hydroxy-benzoate 4-hydroxylase (PHBH, a single-component hydroxylase), 3-hydroxyphenylacetate 4-hydroxylase (HPAH, a two-component hydroxylase), and other monooxygenases which catalyze reactions in addition to hydroxylation, including 2-methyl-3-hydroxypyridine-5-carboxylate oxygenase (MHPCO, a single-component enzyme that catalyzes aromatic-ring cleavage), and HadA monooxygenase (a two-component enzyme that catalyzes additional group elimination reaction). These enzymes have different unique structural features which dictate their reactivity toward various substrates and influence their ability to stabilize flavin intermediates such as C4a-hydroperoxyflavin. Understanding the key catalytic residues and the active site environments important for governing enzyme reactivity will undoubtedly facilitate future work in enzyme engineering or enzyme redesign for the development of biocatalytic methods for the synthesis of valuable compounds.
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Affiliation(s)
- Pirom Chenprakhon
- Institute for Innovative Learning, Mahidol University, Nakhon Pathom, 73170, Thailand
| | - Thanyaporn Wongnate
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, 21210, Thailand
| | - Pimchai Chaiyen
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, 21210, Thailand.,Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, 14000, Thailand
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9
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Pimviriyakul P, Wongnate T, Tinikul R, Chaiyen P. Microbial degradation of halogenated aromatics: molecular mechanisms and enzymatic reactions. Microb Biotechnol 2020; 13:67-86. [PMID: 31565852 PMCID: PMC6922536 DOI: 10.1111/1751-7915.13488] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 09/01/2019] [Accepted: 09/03/2019] [Indexed: 12/12/2022] Open
Abstract
Halogenated aromatics are used widely in various industrial, agricultural and household applications. However, due to their stability, most of these compounds persist for a long time, leading to accumulation in the environment. Biological degradation of halogenated aromatics provides sustainable, low-cost and environmentally friendly technologies for removing these toxicants from the environment. This minireview discusses the molecular mechanisms of the enzymatic reactions for degrading halogenated aromatics which naturally occur in various microorganisms. In general, the biodegradation process (especially for aerobic degradation) can be divided into three main steps: upper, middle and lower metabolic pathways which successively convert the toxic halogenated aromatics to common metabolites in cells. The most difficult step in the degradation of halogenated aromatics is the dehalogenation step in the middle pathway. Although a variety of enzymes are involved in the degradation of halogenated aromatics, these various pathways all share the common feature of eventually generating metabolites for utilizing in the energy-producing metabolic pathways in cells. An in-depth understanding of how microbes employ various enzymes in biodegradation can lead to the development of new biotechnologies via enzyme/cell/metabolic engineering or synthetic biology for sustainable biodegradation processes.
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Affiliation(s)
- Panu Pimviriyakul
- Department of BiotechnologyFaculty of Engineering and Industrial TechnologySilpakorn UniversityNakhon Pathom73000Thailand
| | - Thanyaporn Wongnate
- School of Biomolecular Science and EngineeringVidyasirimedhi Institute of Science and Technology (VISTEC)Wangchan ValleyRayong21210Thailand
| | - Ruchanok Tinikul
- Department of Biochemistry and Center for Excellence in Protein and Enzyme TechnologyFaculty of ScienceMahidol UniversityBangkok10400Thailand
| | - Pimchai Chaiyen
- School of Biomolecular Science and EngineeringVidyasirimedhi Institute of Science and Technology (VISTEC)Wangchan ValleyRayong21210Thailand
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10
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Morya R, Kumar M, Singh SS, Thakur IS. Genomic analysis of Burkholderia sp. ISTR5 for biofunneling of lignin-derived compounds. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:277. [PMID: 31788027 PMCID: PMC6880542 DOI: 10.1186/s13068-019-1606-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 10/29/2019] [Indexed: 05/25/2023]
Abstract
BACKGROUND Lignin is the second most abundant natural polymer on earth. Industries using lignocellulosic biomass as feedstock generate a considerable amount of lignin as a byproduct with minimal usage. For a sustainable biorefinery, the lignin must be utilized in improved ways. Lignin is recalcitrant to degradation due to the complex and heterogeneous structure. The depolymerization of lignin and its conversion into specific product stream are the major challenges associated with lignin valorization. The blend of oligomeric, dimeric and monomeric lignin-derived compounds (LDCs) generated during depolymerization can be utilized by microbes for production of bioproducts. RESULTS In the present study, a novel bacterium Burkholderia sp. strain ISTR5 (R5), a proteobacteria belonging to class betaproteobacteria, order Burkholderiales and family Burkholderiaceae, was isolated and characterized for the degradation of LDCs. R5 strain was cultured on 12 LDCs in mineral salt medium (MSM) supplemented with individual compounds such as syringic acid, p-coumaric acid, ferulic acid, vanillin, vanillic acid, guaiacol, 4-hydroxybenzoic acid, gallic acid, benzoic acid, syringaldehyde, veratryl alcohol and catechol. R5 was able to grow and utilize all the selected LDCs. The degradation of selected LDCs was monitored by bacterial growth, total organic carbon (TOC) removal and UV-Vis absorption spectra in scan mode. TOC reduction shown in the sample contains syringic acid 80.7%, ferulic acid 84.1%, p-coumaric acid 85.9% and benzoic acid 83.2%. In UV-Vis absorption spectral scan, most of the lignin-associated peaks were found at or near 280 nm wavelength in the obtained absorption spectra. Enzyme assay for the ligninolytic enzymes was also performed, and it was observed that lignin peroxidase and laccase were predominantly expressed. Furthermore, the GC-MS analysis of LDCs was performed to identify the degradation intermediates from these compounds. The genomic analysis showed the robustness of this strain and identified various candidate genes responsible for the degradation of aromatic or lignin derivatives, detoxification mechanism, oxidative stress response and fatty acid synthesis. The presence of peroxidases (13%), laccases (4%), monooxygenases (23%), dioxygenase (44%), NADPH: quinone oxidoreductases (16%) and many other related enzymes supported the degradation of LDCs. CONCLUSION Numerous pathway intermediates were observed during experiment. Vanillin was found during growth on syringic acid, ferulic acid and p-coumaric acid. Some other intermediates like catechol, acetovanillone, syringaldehyde and 3,4-dihydroxybenzaldehyde from the recognized bacterial metabolic pathways existed during growth on the LDCs. The ortho- and meta cleavage pathway enzymes, such as the catechol-1,2-dioxygenase, protocatechuate 3,4-dioxygenase, catechol-2,3-dioxygenase and toluene-2,3-dioxygenase, were observed in the genome. In addition to the common aromatic degradation pathways, presence of the epoxyqueuosine reductase, 1,2-epoxyphenylacetyl-CoA isomerase in the genome advocates that this strain may follow the epoxy Coenzyme A thioester pathway for degradation.
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Affiliation(s)
- Raj Morya
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, 110067 India
| | - Madan Kumar
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, 110067 India
| | - Shashi Shekhar Singh
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, 110067 India
| | - Indu Shekhar Thakur
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, 110067 India
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11
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Liu Z, Xia B, Saric J, Utzinger J, Holmes E, Keiser J, Li JV. Effects of Vancomycin and Ciprofloxacin on the NMRI Mouse Metabolism. J Proteome Res 2018; 17:3565-3573. [DOI: 10.1021/acs.jproteome.8b00583] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Zhigang Liu
- Division of Integrative Systems Medicine and Digestive Disease, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Bing Xia
- Division of Integrative Systems Medicine and Digestive Disease, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Jasmina Saric
- Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland
- University of Basel, P.O. Box, CH-4003, Basel, Switzerland
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland
- University of Basel, P.O. Box, CH-4003, Basel, Switzerland
| | - Elaine Holmes
- Division of Integrative Systems Medicine and Digestive Disease, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Jennifer Keiser
- Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland
- University of Basel, P.O. Box, CH-4003, Basel, Switzerland
| | - Jia V. Li
- Division of Integrative Systems Medicine and Digestive Disease, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
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12
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Yuenyao A, Petchyam N, Kamonsutthipaijit N, Chaiyen P, Pakotiprapha D. Crystal structure of the flavin reductase of Acinetobacter baumannii p-hydroxyphenylacetate 3-hydroxylase (HPAH) and identification of amino acid residues underlying its regulation by aromatic ligands. Arch Biochem Biophys 2018; 653:24-38. [PMID: 29940152 DOI: 10.1016/j.abb.2018.06.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 06/07/2018] [Accepted: 06/21/2018] [Indexed: 10/28/2022]
Abstract
The first step in the degradation of p-hydroxyphenylacetic acid (HPA) is catalyzed by the two-component enzyme p-hydroxyphenylacetate 3-hydroxylase (HPAH). The two components of Acinetobacter baumannii HPAH are known as C1 and C2, respectively. C1 is a flavin reductase that uses NADH to generate reduced flavin mononucleotide (FMNH-), which is used by C2 in the hydroxylation of HPA. Interestingly, although HPA is not directly involved in the reaction catalyzed by C1, the presence of HPA dramatically increases the FMN reduction rate. Amino acid sequence analysis revealed that C1 contains two domains: an N-terminal flavin reductase domain, and a C-terminal MarR domain. Although MarR proteins typically function as transcription regulators, the MarR domain of C1 was found to play an auto-inhibitory role. Here, we report a crystal structure of C1 and small-angle X-ray scattering (SAXS) studies that revealed that C1 undergoes a substantial conformational change in the presence of HPA, concomitant with the increase in the rate of flavin reduction. Amino acid residues that are important for HPA binding and regulation of C1 activity were identified by site-directed mutagenesis. Amino acid sequence similarity analysis revealed several as yet uncharacterized flavin reductases with N- or C-terminal fusions.
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Affiliation(s)
- Anan Yuenyao
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Nopphon Petchyam
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | | | - Pimchai Chaiyen
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology Faculty of Science, Mahidol University, Bangkok, 10400, Thailand; School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, 21210, Thailand
| | - Danaya Pakotiprapha
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.
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13
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Phonbuppha J, Maenpuen S, Munkajohnpong P, Chaiyen P, Tinikul R. Selective determination of the catalytic cysteine pK a of two-cysteine succinic semialdehyde dehydrogenase from Acinetobacter baumannii using burst kinetics and enzyme adduct formation. FEBS J 2018; 285:2504-2519. [PMID: 29734522 DOI: 10.1111/febs.14497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 03/27/2018] [Accepted: 04/30/2018] [Indexed: 11/27/2022]
Abstract
Succinic semialdehyde dehydrogenase (SSADH) from Acinetobacter baumannii (Ab) catalyzes the oxidation of succinic semialdehyde (SSA). This enzyme has two conserved cysteines (Cys289 and Cys291) and preferentially uses NADP+ over NAD+ as a hydride acceptor. Steady-state kinetic analysis showed that AbSSADH has the highest catalytic turnover (137 s-1 ) and can tolerate SSA inhibition the most (< 500 μm) among all SSADHs reported. Alanine substitutions of the two conserved cysteines indicated that Cys291Ala has ~ 65% activity compared with the wild-type enzyme while Cys289Ala is inactive, suggesting that Cys289 is the active residue participating in catalysis. Pre-steady-state kinetics showed for the first time burst kinetics for NADPH formation in SSADH, indicating that the rate-limiting step is associated with steps that occur after the hydride transfer. As the magnitude of burst kinetics represents the amount of NADPH formed during the first turnover, it is directly dependent on the amount of the deprotonated form of cysteine. The pKa of Cys289 was calculated from a plot of the burst magnitude vs pH as 7.4 ± 0.2. The Cys289 pKa was also measured based on the ability of AbSSADH to form an NADP-cysteine adduct, which can be detected by the increase of absorbance at ~ 330 nm as 7.9 ± 0.2. The lowering of the catalytic cysteine pKa by 0.6-1 unit renders the catalytic thiol more nucleophilic, which facilitates AbSSADH catalysis under physiological conditions. The methods established herein can specifically measure the active site cysteine pKa without interference from other cysteines. These techniques may be useful for studying ionization state of other cysteine-containing aldehyde dehydrogenases. ENZYME Succinic semialdehyde dehydrogenase, EC1.2.1.24.
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Affiliation(s)
- Jittima Phonbuppha
- Department of Biomolecular Science and Engineering, School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand.,Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Somchart Maenpuen
- Department of Biochemistry, Faculty of Science, Burapha University, Chonburi, Thailand
| | - Pobthum Munkajohnpong
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Pimchai Chaiyen
- Department of Biomolecular Science and Engineering, School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand.,Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Ruchanok Tinikul
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand.,Mahidol University, Nakhonsawan, Thailand
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14
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Tinikul R, Chenprakhon P, Maenpuen S, Chaiyen P. Biotransformation of Plant-Derived Phenolic Acids. Biotechnol J 2018; 13:e1700632. [DOI: 10.1002/biot.201700632] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 12/10/2017] [Indexed: 01/18/2023]
Affiliation(s)
- Ruchanok Tinikul
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology; Faculty of Science; Mahidol University; Bangkok 10400 Thailand
| | - Pirom Chenprakhon
- Institute for Innovative Learning; Mahidol University; Nakhon Pathom 73170 Thailand
| | - Somchart Maenpuen
- Department of Biochemistry; Faculty of Science; Burapha University; Chonburi 20131 Thailand
| | - Pimchai Chaiyen
- Department of Biomolecular Science and Engineering; School of Biomolecular Science & Engineering; Vidyasirimedhi Institute of Science and Technology (VISTEC); Wangchan Valley Rayong 21210 Thailand
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15
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Quan Y, Wu H, Yin Z, Fang Y, Yin C. Effect of static magnetic field on trichloroethylene removal in a biotrickling filter. BIORESOURCE TECHNOLOGY 2017; 239:7-16. [PMID: 28500890 DOI: 10.1016/j.biortech.2017.04.121] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 04/25/2017] [Accepted: 04/28/2017] [Indexed: 06/07/2023]
Abstract
A laboratory-scale biotrickling filter combined with a magnetic field (MF-BTF) and a single BTF (S-BTF) were set up to treat trichloroethylene (TCE) gas. The influences of phenol alone and NaAc-phenol as co-substrates and different MF intensities were investigated. At low MF intensity, MF-BTF displayed better performance with 0.20g/L of phenol, 53.6-337.1mg/m3 of TCE, and empty bed residence times of 202.5s. The performances followed the order MF-BTF (60.0mT)>MF-BTF (30.0mT)>S-BTF (0mT)>MF-BTF (130.0mT), and the removal efficiencies (REs) and maximum elimination capacities (ECs) corresponded to: 92.2%-45.5%, 2656.8mg/m3h; 89.8%-37.2%, 2169.1mg/m3h; 89.8%-29.8%, 1967.7mg/m3h; 76.0%-20.8%, 1697.1mg/m3h, respectively. High-throughput sequencing indicated that the bacterial diversity was lower, whereas the relative abundances of Acinetobacter, Chryseobacterium, and Acidovorax were higher in MF-BTF. Results confirmed that a proper MF could improve TCE removal performance in BTF.
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Affiliation(s)
- Yue Quan
- Key Laboratory of Natural Resources of Changbai Mountain and Functional Molecules, Ministry of Education, Yanbian University, Yanji 133002, China; Department of Environmental Science, Agricultural College, Yanbian University, Yanji 133002, China
| | - Hao Wu
- Key Laboratory of Natural Resources of Changbai Mountain and Functional Molecules, Ministry of Education, Yanbian University, Yanji 133002, China
| | - Zhenhao Yin
- Analytical and Testing Center, Yanbian University, Yanji 133002, China
| | - Yingyu Fang
- Analytical and Testing Center, Yanbian University, Yanji 133002, China
| | - Chengri Yin
- Key Laboratory of Natural Resources of Changbai Mountain and Functional Molecules, Ministry of Education, Yanbian University, Yanji 133002, China.
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16
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Gerlt JA. Genomic Enzymology: Web Tools for Leveraging Protein Family Sequence-Function Space and Genome Context to Discover Novel Functions. Biochemistry 2017; 56:4293-4308. [PMID: 28826221 PMCID: PMC5569362 DOI: 10.1021/acs.biochem.7b00614] [Citation(s) in RCA: 140] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
![]()
The exponentially increasing number
of protein and nucleic acid
sequences provides opportunities to discover novel enzymes, metabolic
pathways, and metabolites/natural products, thereby adding to our
knowledge of biochemistry and biology. The challenge has evolved from
generating sequence information to mining the databases to integrating
and leveraging the available information, i.e., the availability of
“genomic enzymology” web tools. Web tools that allow
identification of biosynthetic gene clusters are widely used by the
natural products/synthetic biology community, thereby facilitating
the discovery of novel natural products and the enzymes responsible
for their biosynthesis. However, many novel enzymes with interesting
mechanisms participate in uncharacterized small-molecule metabolic
pathways; their discovery and functional characterization also can
be accomplished by leveraging information in protein and nucleic acid
databases. This Perspective focuses on two genomic enzymology web
tools that assist the discovery novel metabolic pathways: (1) Enzyme
Function Initiative-Enzyme Similarity Tool (EFI-EST) for generating
sequence similarity networks to visualize and analyze sequence–function
space in protein families and (2) Enzyme Function Initiative-Genome
Neighborhood Tool (EFI-GNT) for generating genome neighborhood networks
to visualize and analyze the genome context in microbial and fungal
genomes. Both tools have been adapted to other applications to facilitate
target selection for enzyme discovery and functional characterization.
As the natural products community has demonstrated, the enzymology
community needs to embrace the essential role of web tools that allow
the protein and genome sequence databases to be leveraged for novel
insights into enzymological problems.
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Affiliation(s)
- John A Gerlt
- Departments of Biochemistry and Chemistry, Institute for Genomic Biology, University of Illinois , Urbana-Champaign Urbana, Illinois 61801, United States
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17
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Pornsuwan S, Maenpuen S, Kamutira P, Watthaisong P, Thotsaporn K, Tongsook C, Juttulapa M, Nijvipakul S, Chaiyen P. 3,4-Dihydroxyphenylacetate 2,3-dioxygenase from Pseudomonas aeruginosa: An Fe(II)-containing enzyme with fast turnover. PLoS One 2017; 12:e0171135. [PMID: 28158217 PMCID: PMC5291488 DOI: 10.1371/journal.pone.0171135] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 01/15/2017] [Indexed: 11/18/2022] Open
Abstract
3,4-dihydroxyphenylacetate (DHPA) dioxygenase (DHPAO) from Pseudomonas aeruginosa (PaDHPAO) was overexpressed in Escherichia coli and purified to homogeneity. As the enzyme lost activity over time, a protocol to reactivate and conserve PaDHPAO activity has been developed. Addition of Fe(II), DTT and ascorbic acid or ROS scavenging enzymes (catalase or superoxide dismutase) was required to preserve enzyme stability. Metal content and activity analyses indicated that PaDHPAO uses Fe(II) as a metal cofactor. NMR analysis of the reaction product indicated that PaDHPAO catalyzes the 2,3-extradiol ring-cleavage of DHPA to form 5-carboxymethyl-2-hydroxymuconate semialdehyde (CHMS) which has a molar absorptivity of 32.23 mM-1cm-1 at 380 nm and pH 7.5. Steady-state kinetics under air-saturated conditions at 25°C and pH 7.5 showed a Km for DHPA of 58 ± 8 μM and a kcat of 64 s-1, indicating that the turnover of PaDHPAO is relatively fast compared to other DHPAOs. The pH-rate profile of the PaDHPAO reaction shows a bell-shaped plot that exhibits a maximum activity at pH 7.5 with two pKa values of 6.5 ± 0.1 and 8.9 ± 0.1. Study of the effect of temperature on PaDHPAO activity indicated that the enzyme activity increases as temperature increases up to 55°C. The Arrhenius plot of ln(k’cat) versus the reciprocal of the absolute temperature shows two correlations with a transition temperature at 35°C. Two activation energy values (Ea) above and below the transition temperature were calculated as 42 and 14 kJ/mol, respectively. The data imply that the rate determining steps of the PaDHPAO reaction at temperatures above and below 35°C may be different. Sequence similarity network analysis indicated that PaDHPAO belongs to the enzyme clusters that are largely unexplored. As PaDHPAO has a high turnover number compared to most of the enzymes previously reported, understanding its biochemical and biophysical properties should be useful for future applications in biotechnology.
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Affiliation(s)
- Soraya Pornsuwan
- Department of Chemistry, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Somchart Maenpuen
- Department of Biochemistry, Faculty of Science, Burapha University, Chonburi, Thailand
| | - Philaiwarong Kamutira
- Department of Biochemistry, Faculty of Science, Burapha University, Chonburi, Thailand
| | - Pratchaya Watthaisong
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Kittisak Thotsaporn
- Department of Biochemistry, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - Chanakan Tongsook
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Maneerat Juttulapa
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Sarayut Nijvipakul
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Pimchai Chaiyen
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand
- * E-mail:
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