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Pardhe BD, Lee MJ, Lee JH, Do H, Oh TJ. Biochemical and structural basis of mercuric reductase, GbsMerA, from Gelidibacter salicanalis PAMC21136. Sci Rep 2023; 13:17854. [PMID: 37857791 PMCID: PMC10587081 DOI: 10.1038/s41598-023-44968-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Accepted: 10/13/2023] [Indexed: 10/21/2023] Open
Abstract
Heavy metals, including mercury, are non-biodegradable and highly toxic to microorganisms even at low concentrations. Understanding the mechanisms underlying the environmental adaptability of microorganisms with Hg resistance holds promise for their use in Hg bioremediation. We characterized GbsMerA, a mercury reductase belonging to the mercury-resistant operon of Gelidibacter salicanalis PAMC21136, and found its maximum activity of 474.7 µmol/min/mg in reducing Hg+2. In the presence of Ag and Mn, the enzyme exhibited moderate activity as 236.5 µmol/min/mg and 69 µmol/min/mg, respectively. GbsMerA exhibited optimal activity at pH 7.0 and a temperature of 60 °C. Moreover, the crystal structure of GbsMerA and structural comparison with homologues indicated that GbsMerA contains residues, Tyr437´ and Asp47, which may be responsible for metal transfer at the si-face by providing a hydroxyl group (-OH) to abstract a proton from the thiol group of cysteine. The complex structure with NADPH indicated that Y174 in the re-face can change its side chain direction upon NADPH binding, indicating that Y174 may have a role as a gate for NADPH binding. Moreover, the heterologous host expressing GbsMerA (pGbsMerA) is more resistant to Hg toxicity when compared to the host lacking GbsMerA. Overall, this study provides a background for understanding the catalytic mechanism and Hg detoxification by GbsMerA and suggests the application of genetically engineered E. coli strains for environmental Hg removal.
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Affiliation(s)
- Bashu Dev Pardhe
- Department of Life Science and Biochemical Engineering, Graduate School, SunMoon University, Asan, 31460, Republic of Korea
| | - Min Ju Lee
- Research Unit of Cryogenic Novel Material, Korea Polar Research Institute, Incheon, 21990, Republic of Korea
| | - Jun Hyuck Lee
- Research Unit of Cryogenic Novel Material, Korea Polar Research Institute, Incheon, 21990, Republic of Korea
- Department of Polar Sciences, University of Science and Technology, Incheon, 21990, Republic of Korea
| | - Hackwon Do
- Research Unit of Cryogenic Novel Material, Korea Polar Research Institute, Incheon, 21990, Republic of Korea.
- Department of Polar Sciences, University of Science and Technology, Incheon, 21990, Republic of Korea.
| | - Tae-Jin Oh
- Department of Life Science and Biochemical Engineering, Graduate School, SunMoon University, Asan, 31460, Republic of Korea.
- Genome-Based BioIT Convergence Institute, Asan, 31460, Republic of Korea.
- Department of Pharmaceutical Engineering and Biotechnology, SunMoon University, Asan, 31460, Republic of Korea.
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Liu Y, Jia K, Chen H, Wang Z, Zhao W, Zhu L. Cold-adapted enzymes: mechanisms, engineering and biotechnological application. Bioprocess Biosyst Eng 2023; 46:1399-1410. [PMID: 37486422 DOI: 10.1007/s00449-023-02904-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 07/05/2023] [Indexed: 07/25/2023]
Abstract
Most cold-adapted enzymes display high catalytic activity at low temperatures (20-25 °C) and can still maintain more than 40-50% of their maximum activity at lower temperatures (0-10 °C) but are inactivated after a moderate increase in temperature. The activity of some cold-adapted enzymes increases significantly in the presence of high salt concentrations and metal ions. Interestingly, we also observed that some cold-adapted enzymes have a wide range of optimum temperatures, exhibiting not only maximum activity under low-temperature conditions but also the ability to maintain high enzyme activity under high-temperature conditions, which is a novel feature of cold-adapted enzymes. This unique property of cold-adapted enzymes is generally attractive for biotechnological and industrial applications because these enzymes can reduce energy consumption and the chance of microbial contamination, thereby lowering the production costs and maintaining the flavor, taste and quality of foods. How high catalytic activity is maintained at low temperatures remains unknown. The relationship between the structure of cold-adapted enzymes and their activity, flexibility and stability is complex, and thus far, a unified explanation has not been provided. Herein, we systematically review the sources, catalytic characteristics and cold adaptation of enzymes from four enzymes categories systematically and discuss how these properties may be exploited in biotechnology. A thorough understanding of the properties, catalytic mechanisms, and engineering of cold-adapted enzymes is critical for future biotechnological applications in the detergent industry and food and beverage industries.
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Affiliation(s)
- Yan Liu
- Cooperative Innovation Center of Industrial Fermentation (Ministry of Education and Hubei Province), Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei Key Laboratory of Industrial Microbiology, National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, 430068, China
| | - Kaizhi Jia
- Cooperative Innovation Center of Industrial Fermentation (Ministry of Education and Hubei Province), Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei Key Laboratory of Industrial Microbiology, National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, 430068, China
| | - Hongyang Chen
- Cooperative Innovation Center of Industrial Fermentation (Ministry of Education and Hubei Province), Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei Key Laboratory of Industrial Microbiology, National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, 430068, China
| | - Zhulin Wang
- Cooperative Innovation Center of Industrial Fermentation (Ministry of Education and Hubei Province), Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei Key Laboratory of Industrial Microbiology, National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, 430068, China
| | - Wei Zhao
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China
| | - Liwen Zhu
- Cooperative Innovation Center of Industrial Fermentation (Ministry of Education and Hubei Province), Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei Key Laboratory of Industrial Microbiology, National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, 430068, China.
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Li Y, Huang D, Sun W, Sun X, Yan G, Gao W, Lin H. Characterizing sediment bacterial community and identifying the biological indicators in a seawater-freshwater transition zone during the wet and dry seasons. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:41219-41230. [PMID: 35088267 DOI: 10.1007/s11356-021-18053-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 12/07/2021] [Indexed: 06/14/2023]
Abstract
Seawater intrusion has a detrimental effect on agriculture, industry, and human health. One question of particular interest is how the microbial community responds to and reflects seawater intrusion with seasonal variation. The current study explored the seasonal changes in bacterial community composition and interaction in the vicinity of Pearl River Estuary in dry season (January) and wet season (September). Results indicated that the salinity of sediment samples obtained in dry season was higher than that in wet season. The salt stress induced a declined alpha diversity but resulted in a loosely connected and unstable biotic interaction network in the bacterial communities. Random forest prediction and redundancy analysis of bacterial community indicated that salinity substantially affected the bacterial communities. Multiple lines of evidence, including the enrichment of bacterial taxa in the high-salinity location, microbe-microbe interactions, environment-microbe interactions, and machine learning approach, demonstrated that the families Moraxellaceae and Planococcaceae were the keystone taxa and were resistant to salt stress, which suggested that both of them can be used as potential biological indicators of monitoring and controlling seawater intrusion in coastal zone areas.
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Affiliation(s)
- Yongbin Li
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, Tianhe District, 808 Tianyuan Road, Guangzhou, 510650, Guangdong, China
| | - Duanyi Huang
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, Tianhe District, 808 Tianyuan Road, Guangzhou, 510650, Guangdong, China
| | - Weimin Sun
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, Tianhe District, 808 Tianyuan Road, Guangzhou, 510650, Guangdong, China
| | - Xiaoxu Sun
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, Tianhe District, 808 Tianyuan Road, Guangzhou, 510650, Guangdong, China
| | - Geng Yan
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, Tianhe District, 808 Tianyuan Road, Guangzhou, 510650, Guangdong, China
| | - Wenlong Gao
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, Tianhe District, 808 Tianyuan Road, Guangzhou, 510650, Guangdong, China
| | - Hanzhi Lin
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, Tianhe District, 808 Tianyuan Road, Guangzhou, 510650, Guangdong, China.
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Dixit N. Salinity Induced Antioxidant Defense in Roots of Industrial Hemp (IH: Cannabis sativa L.) for Fiber during Seed Germination. Antioxidants (Basel) 2022; 11:antiox11020244. [PMID: 35204127 PMCID: PMC8868197 DOI: 10.3390/antiox11020244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 01/19/2022] [Accepted: 01/26/2022] [Indexed: 01/06/2023] Open
Abstract
Global climate change induced sea level rise, rainfed agriculture, poor quality irrigation water, and seawater intrusion through interconnected ditches and inland waterways cause soil salinity in inland and coastal areas. To reclaim and prevent further soil erosion, salt tolerant crops are required. Industrial Hemp (IH: Cannabis sativa L.) is used for food, fiber, and medicinal purposes throughout the world. In spite of that, little is known about the salt tolerance mechanisms in IH. Seed germination and development of the roots are the primary events in the life cycle of a plant, which directly interact with soil salinity. Therefore, in vitro germination experiments were conducted on the roots of 5-day-old seedlings using four varieties (V1: CFX-2, V2: Joey, V3: Bialobrzeskie, and V4: Henola) of IH for fiber. Five salinity treatments (0, 50, 80, 100, 150, and 200 mM NaCl) were used to screen the IH varieties on the basis of I: seed germination percent (SGP), II: quantitative morphological observations (root length (RL) and root fresh weight (RFW)), III: oxidative stress indices (hydrogen peroxide (H2O2) and lipid peroxidation), and IV: antioxidant defense system comprises of superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (GPOD), ascorbate peroxidase (APOD), glutathione reductase (GR). The varieties V1 and V3 showed salt tolerance up to 100 mM by maintaining higher SGP, less reduction in RL and RFW. These roots in V1 and V3 showed lower levels of H2O2 and lipid peroxidation by displaying higher activities of SOD, CAT, GPOD, APOD, and GR while a reciprocal trend was observed in V4. However, roots in V2 showed higher activities of antioxidant enzymes with lower levels of H2O2 and lipid peroxidation, but showed declines in RL and RFW at 80 mM NaCl onward. Roots in V4 were the most susceptible to NaCl stress at 50 mM and onward.
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Affiliation(s)
- Naveen Dixit
- Department of Agriculture Food and Resources Sciences, University of Maryland Eastern Shore, Princess Anne, MD 21853, USA
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Glutaredoxin Interacts with GR and AhpC to Enhance Low-Temperature Tolerance of Antarctic Psychrophile Psychrobacter sp. ANT206. Int J Mol Sci 2022; 23:ijms23031313. [PMID: 35163237 PMCID: PMC8836231 DOI: 10.3390/ijms23031313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 01/22/2022] [Accepted: 01/22/2022] [Indexed: 02/05/2023] Open
Abstract
Glutaredoxin (Grx) is an important oxidoreductase to maintain the redox homoeostasis of cells. In our previous study, cold-adapted Grx from Psychrobacter sp. ANT206 (PsGrx) has been characterized. Here, we constructed an in-frame deletion mutant of psgrx (Δpsgrx). Mutant Δpsgrx was more sensitive to low temperature, demonstrating that psgrx was conducive to the growth of ANT206. Mutant Δpsgrx also had more malondialdehyde (MDA) and protein carbonylation content, suggesting that PsGrx could play a part in the regulation of tolerance against low temperature. A yeast two-hybrid system was adopted to screen interacting proteins of 26 components. Furthermore, two target proteins, glutathione reductase (GR) and alkyl hydroperoxide reductase subunit C (AhpC), were regulated by PsGrx under low temperature, and the interactions were confirmed via bimolecular fluorescence complementation (BiFC) and co-immunoprecipitation (Co-IP). Moreover, PsGrx could enhance GR activity. trxR expression in Δpsgrx, Δahpc, and ANT206 were illustrated 3.7, 2.4, and 10-fold more than mutant Δpsgrx Δahpc, indicating that PsGrx might increase the expression of trxR by interacting with AhpC. In conclusion, PsGrx may participate in glutathione metabolism and ROS-scavenging by regulating GR and AhpC to protect the growth of ANT206. These findings preliminarily suggest the role of PsGrx in the regulation of oxidative stress, which could improve the low-temperature tolerance of ANT206.
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Wang Y, Hou Y, Wang Q. Cloning, Expression, Characterization, and Antioxidant Protection of Glutaredoxin3 From Psychrophilic Bacterium Psychrobacter sp. ANT206. Front Microbiol 2021; 12:633362. [PMID: 33897638 PMCID: PMC8060642 DOI: 10.3389/fmicb.2021.633362] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 03/18/2021] [Indexed: 11/13/2022] Open
Abstract
Glutaredoxins (Grxs) are proteins that catalyze the glutathione (GSH)-dependent reduction of protein disulfides. In this study, a Grx-related gene (264 bp), encoding a Ps-Grx3, was cloned from Psychrobacter sp. ANT206. Sequence analysis indicated the presence of the active site motif CPYC in this protein. Homology modeling showed that Ps-Grx3 had fewer hydrogen bonds and salt bridges, as well as a lower Arg/(Arg + Lys) ratio than its mesophilic homologs, indicative of an improved catalytic ability at low temperatures. Site-directed mutagenesis demonstrated that the Cys13, Pro14, and Cys16 sites were essential for the catalytic activity of Ps-Grx3, while circular dichroism (CD) spectroscopy confirmed that point mutations in these amino acid residues led to the loss or reduction of enzyme activity. Furthermore, analysis of the biochemical properties of Ps-Grx3 showed that the optimum temperature of this enzyme was 25 °C. Importantly, Ps-Grx3 was more sensitive to tBHP and CHP than to H2O2, and retained approximately 40% activity even when the H2O2 concentration was increased to 1 mm Regarding substrate specificity, Ps-Grx3 had a higher affinity for HED, L-cystine, and DHA than for S-sulfocysteine and BSA. We also investigated the DNA-protective ability of Ps-Grx3 using the pUC19 plasmid, and found that Ps-Grx3 could protect supercoiled DNA from oxidation-induced damage at 15°C for 1.5 h. This study provides new insights into the structure and catalytic activity of a cold-adapted Grx3.
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Affiliation(s)
- Yatong Wang
- School of Environment, Harbin Institute of Technology, Harbin, China
| | - Yanhua Hou
- School of Marine Science and Technology, Harbin Institute of Technology, Weihai, China
| | - Quanfu Wang
- School of Environment, Harbin Institute of Technology, Harbin, China.,School of Marine Science and Technology, Harbin Institute of Technology, Weihai, China
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