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Investigations of Dimethylglycine, Glycine Betaine, and Ectoine Uptake by a Betaine-Carnitine-Choline Transporter Family Transporter with Diverse Substrate Specificity in Vibrio Species. J Bacteriol 2020; 202:JB.00314-20. [PMID: 32817090 DOI: 10.1128/jb.00314-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 08/06/2020] [Indexed: 01/08/2023] Open
Abstract
Fluctuations in osmolarity are one of the most prevalent stresses to which bacteria must adapt, both hypo- and hyperosmotic conditions. Most bacteria cope with high osmolarity by accumulating compatible solutes (osmolytes) in the cytoplasm to maintain the turgor pressure of the cell. Vibrio parahaemolyticus, a halophile, utilizes at least six compatible solute transporters for the uptake of osmolytes: two ABC family ProU transporters and four betaine-carnitine-choline transporter (BCCT) family transporters. The full range of compatible solutes transported by this species has yet to be determined. Using an osmolyte phenotypic microarray plate for growth analyses, we expanded the known osmolytes used by V. parahaemolyticus to include N,N-dimethylglycine (DMG), among others. Growth pattern analysis of four triple-bccT mutants, possessing only one functional BCCT, indicated that BccT1 (VP1456), BccT2 (VP1723), and BccT3 (VP1905) transported DMG. BccT1 was unusual in that it could take up both compounds with methylated head groups (glycine betaine [GB], choline, and DMG) and cyclic compounds (ectoine and proline). Bioinformatics analysis identified the four coordinating amino acid residues for GB in the BccT1 protein. In silico modeling analysis demonstrated that GB, DMG, and ectoine docked in the same binding pocket in BccT1. Using site-directed mutagenesis, we showed that a strain with all four residues mutated resulted in the loss of uptake of GB, DMG, and ectoine. We showed that three of the four residues were essential for ectoine uptake, whereas only one of the residues was important for GB uptake. Overall, we have demonstrated that DMG is a highly effective compatible solute for Vibrio species and have elucidated the amino acid residues in BccT1 that are important for the coordination of GB, DMG, and ectoine transport.IMPORTANCE Vibrio parahaemolyticus possesses at least six osmolyte transporters, which allow the bacterium to adapt to high-salinity conditions. In this study, we identified several additional osmolytes that were utilized by V. parahaemolyticus We demonstrated that the compound DMG, which is present in the marine environment, was a highly effective osmolyte for Vibrio species. We determined that DMG is transported via BCCT family carriers, which have not been shown previously to take up this compound. BccT1 was a carrier for GB, DMG, and ectoine, and we identified the amino acid residues essential for the coordination of these compounds. The data suggest that for BccT1, GB is more easily accommodated than ectoine in the transporter binding pocket.
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Microbial Degradation of Pyridine: a Complete Pathway in Arthrobacter sp. Strain 68b Deciphered. Appl Environ Microbiol 2020; 86:AEM.00902-20. [PMID: 32471913 DOI: 10.1128/aem.00902-20] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 05/23/2020] [Indexed: 11/20/2022] Open
Abstract
Pyridine and its derivatives constitute the majority of heterocyclic aromatic compounds that occur largely as a result of human activities and contribute to environmental pollution. It is known that they can be degraded by various bacteria in the environment; however, the degradation of unsubstituted pyridine has not yet been completely resolved. In this study, we present data on the pyridine catabolic pathway in Arthrobacter sp. strain 68b at the level of genes, enzymes, and metabolites. The pyr gene cluster, responsible for the degradation of pyridine, was identified in a catabolic plasmid, p2MP. The pathway of pyridine metabolism consisted of four enzymatic steps and ended by the formation of succinic acid. The first step in the degradation of pyridine proceeds through a direct ring cleavage catalyzed by a two-component flavin-dependent monooxygenase system, encoded by pyrA (pyridine monooxygenase) and pyrE genes. The genes pyrB, pyrC, and pyrD were found to encode (Z)-N-(4-oxobut-1-enyl)formamide dehydrogenase, amidohydrolase, and succinate semialdehyde dehydrogenase, respectively. These enzymes participate in the subsequent steps of pyridine degradation. The metabolites of these enzymatic reactions were identified, and this allowed us to reconstruct the entire pyridine catabolism pathway in Arthrobacter sp. 68b.IMPORTANCE The biodegradation pathway of pyridine, a notorious toxicant, is relatively unexplored, as no genetic data related to this process have ever been presented. In this paper, we describe the plasmid-borne pyr gene cluster, which includes the complete set of genes responsible for the degradation of pyridine. A key enzyme, the monooxygenase PyrA, which is responsible for the first step of the catabolic pathway, performs an oxidative cleavage of the pyridine ring without typical activation steps such as reduction or hydroxylation of the heterocycle. This work provides new insights into the metabolism of N-heterocyclic compounds in nature.
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Guo X, Xie C, Wang L, Li Q, Wang Y. Biodegradation of persistent environmental pollutants by Arthrobacter sp. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:8429-8443. [PMID: 30706270 DOI: 10.1007/s11356-019-04358-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 01/23/2019] [Indexed: 05/17/2023]
Abstract
Persistent environmental pollutants are a growing problem around the world. The effective control of the pollutants is of great significance for human health. Some microbes, especially Arthrobacter, can degrade pollutants into nontoxic substances in various ways. Here, we review the biological properties of Arthrobacter adapting to a variety of environmental stresses, including starvation, hypertonic and hypotonic condition, oxidative stress, heavy metal stress, and low-temperature stress. Furthermore, we categorized the Arthrobacter species that can degrade triazines, organophosphorus, alkaloids, benzene, and its derivatives. Metabolic pathways behind the various biodegradation processes are further discussed. This review will be a helpful reference for comprehensive utilization of Arthrobacter species to tackle environmental pollutants.
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Affiliation(s)
- Xiaohong Guo
- College of Veterinary Medicine, Northwest A&F University, No. 22 Xinong Road, Yangling, 712100, Shaanxi, China
| | - Chengyun Xie
- College of Veterinary Medicine, Northwest A&F University, No. 22 Xinong Road, Yangling, 712100, Shaanxi, China
| | - Lijuan Wang
- College of Veterinary Medicine, Northwest A&F University, No. 22 Xinong Road, Yangling, 712100, Shaanxi, China
| | - Qinfan Li
- College of Veterinary Medicine, Northwest A&F University, No. 22 Xinong Road, Yangling, 712100, Shaanxi, China
| | - Yan Wang
- College of Veterinary Medicine, Northwest A&F University, No. 22 Xinong Road, Yangling, 712100, Shaanxi, China.
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Growth of Paenarthrobacter aurescens strain TC1 on atrazine and isopropylamine during osmotic stress. ANN MICROBIOL 2018. [DOI: 10.1007/s13213-018-1364-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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Glycine Betaine Monooxygenase, an Unusual Rieske-Type Oxygenase System, Catalyzes the Oxidative N-Demethylation of Glycine Betaine in Chromohalobacter salexigens DSM 3043. Appl Environ Microbiol 2018; 84:AEM.00377-18. [PMID: 29703733 DOI: 10.1128/aem.00377-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 04/20/2018] [Indexed: 11/20/2022] Open
Abstract
Although some bacteria, including Chromohalobacter salexigens DSM 3043, can use glycine betaine (GB) as a sole source of carbon and energy, little information is available about the genes and their encoded proteins involved in the initial step of the GB degradation pathway. In the present study, the results of conserved domain analysis, construction of in-frame deletion mutants, and an in vivo functional complementation assay suggested that the open reading frames Csal_1004 and Csal_1005, designated bmoA and bmoB, respectively, may act as the terminal oxygenase and the ferredoxin reductase genes in a novel Rieske-type oxygenase system to convert GB to dimethylglycine in C. salexigens DSM 3043. To further verify their function, BmoA and BmoB were heterologously overexpressed in Escherichia coli, and 13C nuclear magnetic resonance analysis revealed that dimethylglycine was accumulated in E. coli BL21(DE3) expressing BmoAB or BmoA. In addition, His-tagged BmoA and BmoB were individually purified to electrophoretic homogeneity and estimated to be a homotrimer and a monomer, respectively. In vitro biochemical analysis indicated that BmoB is an NADH-dependent flavin reductase with one noncovalently bound flavin adenine dinucleotide (FAD) as its prosthetic group. In the presence of BmoB, NADH, and flavin, BmoA could aerobically degrade GB to dimethylglycine with the concomitant production of formaldehyde. BmoA exhibited strict substrate specificity for GB, and its demethylation activity was stimulated by Fe2+ Phylogenetic analysis showed that BmoA belongs to group V of the Rieske nonheme iron oxygenase (RO) family, and all the members in this group were able to use quaternary ammonium compounds as substrates.IMPORTANCE GB is widely distributed in nature. In addition to being accumulated intracellularly as a compatible solute to deal with osmotic stress, it can be utilized by many bacteria as a source of carbon and energy. However, very limited knowledge is presently available about the molecular and biochemical mechanisms for the initial step of the aerobic GB degradation pathway in bacteria. Here, we report the molecular and biochemical characterization of a novel two-component Rieske-type monooxygenase system, GB monooxygenase (BMO), which is responsible for oxidative demethylation of GB to dimethylglycine in C. salexigens DSM 3043. The results gained in this study extend our knowledge on the catalytic reaction of microbial GB degradation to dimethylglycine.
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A nonpyrrolysine member of the widely distributed trimethylamine methyltransferase family is a glycine betaine methyltransferase. Proc Natl Acad Sci U S A 2014; 111:E4668-76. [PMID: 25313086 DOI: 10.1073/pnas.1409642111] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
COG5598 comprises a large number of proteins related to MttB, the trimethylamine:corrinoid methyltransferase. MttB has a genetically encoded pyrrolysine residue proposed essential for catalysis. MttB is the only known trimethylamine methyltransferase, yet the great majority of members of COG5598 lack pyrrolysine, leaving the activity of these proteins an open question. Here, we describe the function of one of the nonpyrrolysine members of this large protein family. Three nonpyrrolysine MttB homologs are encoded in Desulfitobacterium hafniense, a Gram-positive strict anaerobe present in both the environment and human intestine. D. hafniense was found capable of growth on glycine betaine with electron acceptors such as nitrate or fumarate, producing dimethylglycine and CO2 as products. Examination of the genome revealed genes for tetrahydrofolate-linked oxidation of a methyl group originating from a methylated corrinoid protein, but no obvious means to carry out corrinoid methylation with glycine betaine. DSY3156, encoding one of the nonpyrrolysine MttB homologs, was up-regulated during growth on glycine betaine. The recombinant DSY3156 protein converts glycine betaine and cob(I)alamin to dimethylglycine and methylcobalamin. To our knowledge, DSY3156 is the first glycine betaine:corrinoid methyltransferase described, and a designation of MtgB is proposed. In addition, DSY3157, an adjacently encoded protein, was shown to be a methylcobalamin:tetrahydrofolate methyltransferase and is designated MtgA. Homologs of MtgB are widely distributed, especially in marine bacterioplankton and nitrogen-fixing plant symbionts. They are also found in multiple members of the human microbiome, and may play a beneficial role in trimethylamine homeostasis, which in recent years has been directly tied to human cardiovascular health.
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Marques CR, Caetano AL, Haller A, Gonçalves F, Pereira R, Römbke J. Toxicity screening of soils from different mine areas--a contribution to track the sensitivity and variability of Arthrobacter globiformis assay. JOURNAL OF HAZARDOUS MATERIALS 2014; 274:331-341. [PMID: 24797906 DOI: 10.1016/j.jhazmat.2014.03.066] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 03/30/2014] [Accepted: 03/31/2014] [Indexed: 06/03/2023]
Abstract
This study used the Arthrobacter globiformis solid-contact test for assessing the quality of soils collected in areas subjected to past and present mine activities in Europe (uranium mine, Portugal) and North Africa (phosphogypsum pile, Tunisia; iron mine, Morocco). As to discriminate the influence of soils natural variability from the effect of contaminants, toxicity thresholds were derived for this test, based on the dataset of each study area. Furthermore, the test sensitivity and variability was also evaluated. As a result, soils that inhibited A. globiformis dehydrogenase activity above 45% or 50% relatively to the control, were considered to be toxic. Despite the soil metal content determined, the properties of soils seemed to influence dehydrogenase activity. Overall, the contact test provided a coherent outcome comparing to other more time-consuming and effort-demanding ecotoxicological assays. Our results strengthened the feasibility and ecological relevance of this assay, which variability was quite reduced hence suggesting its potential integration within the test battery of tier 1 of soil risk assessment schemes.
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Affiliation(s)
- Catarina R Marques
- Departamento de Biologia & CESAM (Centro de Estudos do Ambiente e do Mar), Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
| | - Ana L Caetano
- Departamento de Biologia & CESAM (Centro de Estudos do Ambiente e do Mar), Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Andreas Haller
- ECT Oekotoxikologie GmbH, Böttgerstraße 2-14, D-65439 Flörsheim a. M., Germany
| | - Fernando Gonçalves
- Departamento de Biologia & CESAM (Centro de Estudos do Ambiente e do Mar), Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Ruth Pereira
- Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal; Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), Universidade do Porto, Rua dos Bragas 289, P 4050-123 Porto, Portugal
| | - Jörg Römbke
- ECT Oekotoxikologie GmbH, Böttgerstraße 2-14, D-65439 Flörsheim a. M., Germany
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Šimoliūnas E, Kaliniene L, Truncaitė L, Zajančkauskaitė A, Staniulis J, Kaupinis A, Ger M, Valius M, Meškys R. Klebsiella phage vB_KleM-RaK2 - a giant singleton virus of the family Myoviridae. PLoS One 2013; 8:e60717. [PMID: 23593293 PMCID: PMC3622015 DOI: 10.1371/journal.pone.0060717] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 03/01/2013] [Indexed: 11/19/2022] Open
Abstract
At 346 kbp in size, the genome of a jumbo bacteriophage vB_KleM-RaK2 (RaK2) is the largest Klebsiella infecting myovirus genome sequenced to date. In total, 272 out of 534 RaK2 ORFs lack detectable database homologues. Based on the similarity to biologically defined proteins and/or MS/MS analysis, 117 of RaK2 ORFs were given a functional annotation, including 28 RaK2 ORFs coding for structural proteins that have no reliable homologues to annotated structural proteins in other organisms. The electron micrographs revealed elaborate spike-like structures on the tail fibers of Rak2, suggesting that this phage is an atypical myovirus. While head and tail proteins of RaK2 are mostly myoviridae-related, the bioinformatics analysis indicate that tail fibers/spikes of this phage are formed from podovirus-like peptides predominantly. Overall, these results provide evidence that bacteriophage RaK2 differs profoundly from previously studied viruses of the Myoviridae family.
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Affiliation(s)
- Eugenijus Šimoliūnas
- Department of Molecular Microbiology and Biotechnology, Institute of Biochemistry, Vilnius University, Vilnius, Lithuania
| | - Laura Kaliniene
- Department of Molecular Microbiology and Biotechnology, Institute of Biochemistry, Vilnius University, Vilnius, Lithuania
- * E-mail:
| | - Lidija Truncaitė
- Department of Molecular Microbiology and Biotechnology, Institute of Biochemistry, Vilnius University, Vilnius, Lithuania
| | - Aurelija Zajančkauskaitė
- Department of Molecular Microbiology and Biotechnology, Institute of Biochemistry, Vilnius University, Vilnius, Lithuania
| | - Juozas Staniulis
- Laboratory of Plant Viruses, Institute of Botany, Nature Research Centre, Vilnius, Lithuania
| | - Algirdas Kaupinis
- Proteomics Centre, Institute of Biochemistry, Vilnius University, Vilnius, Lithuania
| | - Marija Ger
- Proteomics Centre, Institute of Biochemistry, Vilnius University, Vilnius, Lithuania
| | - Mindaugas Valius
- Proteomics Centre, Institute of Biochemistry, Vilnius University, Vilnius, Lithuania
| | - Rolandas Meškys
- Department of Molecular Microbiology and Biotechnology, Institute of Biochemistry, Vilnius University, Vilnius, Lithuania
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