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Gao Y, Cheng H, Song Q, Huang J, Liu J, Pan D, Wu X. Characteristics and catalytic mechanism of a novel multifunctional oxidase, CpmO, for chloramphenicols degradation from Sphingobium sp. WTD-1. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133348. [PMID: 38154177 DOI: 10.1016/j.jhazmat.2023.133348] [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: 09/15/2023] [Revised: 12/08/2023] [Accepted: 12/20/2023] [Indexed: 12/30/2023]
Abstract
Chloramphenicols (CAPs) are ubiquitous emerging pollutants that threaten ecological environments and human health. Microbial and enzyme-based biodegradation strategies offer a cost-effective environmentally friendly approach for CAPs removal from contaminated sites. Here, CpmO, a novel multifunctional oxidase for CAP degradation was identified from the CAP-degrading strain Sphingobium sp. WTD-1. This enzyme was found to be responsible for both the oxidation of the C3-hydroxyl and oxidative cleavage of the C1-C2 bond of CAP, and the oxidative cleavage pathway of CAP was dominant. The catalytic efficiency of CpmO for CAP was 41.6 times that for thiamphenicol (TAP) under the optimal conditions (40 °C, pH 6.0). CpmO was identified as a member of the glucose-methanol-choline oxidoreductase family. Molecular docking and site-directed mutagenesis analysis indicated that CAP was connected to the key amino acid residues E231/E395, K277, and I273/A276 in CpmO through hydrogen bonding, nonclassical hydrogen bonding, and π-π stacking forces, respectively. The catalytic activities of the A276W, K277P, and E231S mutants were found to be 1.1 times, 6.4 times, and 13.2 times higher than that of the wild type, respectively. These findings provide genetic resources and theoretical guidance for future application in biotechnological and metabolic engineering efforts for the remediation of CAPs-contaminated environments.
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Affiliation(s)
- Yongsheng Gao
- Key Laboratory of Agri-food Safety of Anhui Province, College of Resources and Environment, Anhui Agricultural University, Hefei 230036, China
| | - Huan Cheng
- Key Laboratory of Agri-food Safety of Anhui Province, College of Resources and Environment, Anhui Agricultural University, Hefei 230036, China
| | - Qinghui Song
- Key Laboratory of Agri-food Safety of Anhui Province, College of Resources and Environment, Anhui Agricultural University, Hefei 230036, China
| | - Junwei Huang
- Key Laboratory of Agri-food Safety of Anhui Province, College of Resources and Environment, Anhui Agricultural University, Hefei 230036, China
| | - Junwei Liu
- Key Laboratory of Agri-food Safety of Anhui Province, College of Resources and Environment, Anhui Agricultural University, Hefei 230036, China
| | - Dandan Pan
- Key Laboratory of Agri-food Safety of Anhui Province, College of Resources and Environment, Anhui Agricultural University, Hefei 230036, China.
| | - Xiangwei Wu
- Key Laboratory of Agri-food Safety of Anhui Province, College of Resources and Environment, Anhui Agricultural University, Hefei 230036, China.
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Bharathi M, Senthil Kumar N, Chellapandi P. Functional Prediction and Assignment of Methanobrevibacter ruminantium M1 Operome Using a Combined Bioinformatics Approach. Front Genet 2020; 11:593990. [PMID: 33391347 PMCID: PMC7772410 DOI: 10.3389/fgene.2020.593990] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 11/17/2020] [Indexed: 12/11/2022] Open
Abstract
Methanobrevibacter ruminantium M1 (MRU) is a rod-shaped rumen methanogen with the ability to use H2 and CO2, and formate as substrates for methane formation in the ruminants. Enteric methane emitted from this organism can also be influential to the loss of dietary energy in ruminants and humans. To date, there is no successful technology to reduce methane due to a lack of knowledge on its molecular machinery and 73% conserved hypothetical proteins (HPs; operome) whose functions are still not ascertained perceptively. To address this issue, we have predicted and assigned a precise function to HPs and categorize them as metabolic enzymes, binding proteins, and transport proteins using a combined bioinformatics approach. The results of our study show that 257 (34%) HPs have well-defined functions and contributed essential roles in its growth physiology and host adaptation. The genome-neighborhood analysis identified 6 operon-like clusters such as hsp, TRAM, dsr, cbs and cas, which are responsible for protein folding, sudden heat-shock, host defense, and protection against the toxicities in the rumen. The functions predicted from MRU operome comprised of 96 metabolic enzymes with 17 metabolic subsystems, 31 transcriptional regulators, 23 transport, and 11 binding proteins. Functional annotation of its operome is thus more imperative to unravel the molecular and cellular machinery at the systems-level. The functional assignment of its operome would advance strategies to develop new anti-methanogenic targets to mitigate methane production. Hence, our approach provides new insight into the understanding of its growth physiology and lifestyle in the ruminants and also to reduce anthropogenic greenhouse gas emissions worldwide.
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Affiliation(s)
- M Bharathi
- Molecular Systems Engineering Lab, Department of Bioinformatics, School of Life Sciences, Bharathidasan University, Tiruchirappalli, India
| | - N Senthil Kumar
- Human Genetics Lab, Department of Biotechnology, School of Life Sciences, Mizoram University (Central University), Aizawl, India
| | - P Chellapandi
- Molecular Systems Engineering Lab, Department of Bioinformatics, School of Life Sciences, Bharathidasan University, Tiruchirappalli, India
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Oerum S, Roovers M, Rambo RP, Kopec J, Bailey HJ, Fitzpatrick F, Newman JA, Newman WG, Amberger A, Zschocke J, Droogmans L, Oppermann U, Yue WW. Structural insight into the human mitochondrial tRNA purine N1-methyltransferase and ribonuclease P complexes. J Biol Chem 2018; 293:12862-12876. [PMID: 29880640 PMCID: PMC6102140 DOI: 10.1074/jbc.ra117.001286] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 04/24/2018] [Indexed: 01/17/2023] Open
Abstract
Mitochondrial tRNAs are transcribed as long polycistronic transcripts of precursor tRNAs and undergo posttranscriptional modifications such as endonucleolytic processing and methylation required for their correct structure and function. Among them, 5'-end processing and purine 9 N1-methylation of mitochondrial tRNA are catalyzed by two proteinaceous complexes with overlapping subunit composition. The Mg2+-dependent RNase P complex for 5'-end cleavage comprises the methyltransferase domain-containing protein tRNA methyltransferase 10C, mitochondrial RNase P subunit (TRMT10C/MRPP1), short-chain oxidoreductase hydroxysteroid 17β-dehydrogenase 10 (HSD17B10/MRPP2), and metallonuclease KIAA0391/MRPP3. An MRPP1-MRPP2 subcomplex also catalyzes the formation of 1-methyladenosine/1-methylguanosine at position 9 using S-adenosyl-l-methionine as methyl donor. However, a lack of structural information has precluded insights into how these complexes methylate and process mitochondrial tRNA. Here, we used a combination of X-ray crystallography, interaction and activity assays, and small angle X-ray scattering (SAXS) to gain structural insight into the two tRNA modification complexes and their components. The MRPP1 N terminus is involved in tRNA binding and monomer-monomer self-interaction, whereas the C-terminal SPOUT fold contains key residues for S-adenosyl-l-methionine binding and N1-methylation. The entirety of MRPP1 interacts with MRPP2 to form the N1-methylation complex, whereas the MRPP1-MRPP2-MRPP3 RNase P complex only assembles in the presence of precursor tRNA. This study proposes low-resolution models of the MRPP1-MRPP2 and MRPP1-MRPP2-MRPP3 complexes that suggest the overall architecture, stoichiometry, and orientation of subunits and tRNA substrates.
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Affiliation(s)
- Stephanie Oerum
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7BN, United Kingdom
| | | | - Robert P Rambo
- Diamond Light Source, Harwell Science and Innovation Center, Didcot OX11 0QG, United Kingdom
| | - Jola Kopec
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Henry J Bailey
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Fiona Fitzpatrick
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Joseph A Newman
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - William G Newman
- Manchester Centre for Genomic Medicine, Manchester University NHS Foundation Trust, University of Manchester, Manchester, M13 9WL, United Kingdom
| | - Albert Amberger
- Division of Human Genetics, Medical University of Innsbruck, Innsbruck 6020, Austria
| | - Johannes Zschocke
- Division of Human Genetics, Medical University of Innsbruck, Innsbruck 6020, Austria
| | - Louis Droogmans
- Laboratoire de Microbiologie, Universite libre de Bruxelles, 1050 Belgium
| | - Udo Oppermann
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7BN, United Kingdom; Botnar Research Centre, NIHR Oxford Biomedical Research Unit, Oxford OX3 7LD, United Kingdom.
| | - Wyatt W Yue
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7BN, United Kingdom.
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Freas N, Newton P, Perozich J. Analysis of nucleotide diphosphate sugar dehydrogenases reveals family and group-specific relationships. FEBS Open Bio 2016; 6:77-89. [PMID: 27047744 PMCID: PMC4794789 DOI: 10.1002/2211-5463.12022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 12/03/2015] [Accepted: 12/14/2015] [Indexed: 12/02/2022] Open
Abstract
UDP‐glucose dehydrogenase (UDPGDH), UDP‐N‐acetyl‐mannosamine dehydrogenase (UDPNAMDH) and GDP‐mannose dehydrogenase (GDPMDH) belong to a family of NAD+‐linked 4‐electron‐transfering oxidoreductases called nucleotide diphosphate sugar dehydrogenases (NDP‐SDHs). UDPGDH is an enzyme responsible for converting UDP‐d‐glucose to UDP‐d‐glucuronic acid, a product that has different roles depending on the organism in which it is found. UDPNAMDH and GDPMDH convert UDP‐N‐acetyl‐mannosamine to UDP‐N‐acetyl‐mannosaminuronic acid and GDP‐mannose to GDP‐mannuronic acid, respectively, by a similar mechanism to UDPGDH. Their products are used as essential building blocks for the exopolysaccharides found in organisms like Pseudomonas aeruginosa and Staphylococcus aureus. Few studies have investigated the relationships between these enzymes. This study reveals the relationships between the three enzymes by analysing 229 amino acid sequences. Eighteen invariant and several other highly conserved residues were identified, each serving critical roles in maintaining enzyme structure, coenzyme binding or catalytic function. Also, 10 conserved motifs that included most of the conserved residues were identified and their roles proposed. A phylogenetic tree demonstrated relationships between each group and verified group assignment. Finally, group entropy analysis identified novel conservations unique to each NDP‐SDH group, including residue positions critical to NDP‐sugar substrate interaction, enzyme structure and intersubunit contact. These positions may serve as targets for future research. Enzymes UDP‐glucose dehydrogenase (UDPGDH, EC 1.1.1.22).
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Affiliation(s)
- Nicholas Freas
- Department of Biology Franciscan University of Steubenville OH USA
| | - Peter Newton
- Department of Biology Franciscan University of Steubenville OH USA
| | - John Perozich
- Department of Biology Franciscan University of Steubenville OH USA
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