1
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Sharma V, Fedoseyenko D, Joshi S, Abdelwahed S, Begley TP. Phosphomethylpyrimidine Synthase (ThiC): Trapping of Five Intermediates Provides Mechanistic Insights on a Complex Radical Cascade Reaction in Thiamin Biosynthesis. ACS CENTRAL SCIENCE 2024; 10:988-1000. [PMID: 38799670 PMCID: PMC11117688 DOI: 10.1021/acscentsci.4c00125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 03/26/2024] [Accepted: 03/26/2024] [Indexed: 05/29/2024]
Abstract
Phosphomethylpyrimidine synthase (ThiC) catalyzes the conversion of AIR to the thiamin pyrimidine HMP-P. This reaction is the most complex enzyme-catalyzed radical cascade identified to date, and the detailed mechanism has remained elusive. In this paper, we describe the trapping of five new intermediates that provide snapshots of the ThiC reaction coordinate and enable the formulation of a revised mechanism for the ThiC-catalyzed reaction.
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Affiliation(s)
- Vishav Sharma
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Dmytro Fedoseyenko
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Sumedh Joshi
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Sameh Abdelwahed
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Tadhg P. Begley
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States
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2
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Xia C, Zhao Y, Zhang L, Li X, Cheng Y, Wang D, Xu C, Qi M, Wang J, Guo X, Ye X, Huang Y, Shen D, Dou D, Cao H, Li Z, Cui Z. Myxobacteria restrain Phytophthora invasion by scavenging thiamine in soybean rhizosphere via outer membrane vesicle-secreted thiaminase I. Nat Commun 2023; 14:5646. [PMID: 37704617 PMCID: PMC10499793 DOI: 10.1038/s41467-023-41247-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 08/29/2023] [Indexed: 09/15/2023] Open
Abstract
Public metabolites such as vitamins play critical roles in maintaining the ecological functions of microbial community. However, the biochemical and physiological bases for fine-tuning of public metabolites in the microbiome remain poorly understood. Here, we examine the interactions between myxobacteria and Phytophthora sojae, an oomycete pathogen of soybean. We find that host plant and soil microbes complement P. sojae's auxotrophy for thiamine. Whereas, myxobacteria inhibits Phytophthora growth by a thiaminase I CcThi1 secreted into extracellular environment via outer membrane vesicles (OMVs). CcThi1 scavenges the required thiamine and thus arrests the thiamine sharing behavior of P. sojae from the supplier, which interferes with amino acid metabolism and expression of pathogenic effectors, probably leading to impairment of P. sojae growth and pathogenicity. Moreover, myxobacteria and CcThi1 are highly effective in regulating the thiamine levels in soil, which is correlated with the incidence of soybean Phytophthora root rot. Our findings unravel a novel ecological tactic employed by myxobacteria to maintain the interspecific equilibrium in soil microbial community.
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Affiliation(s)
- Chengyao Xia
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yuqiang Zhao
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing, 210014, China
| | - Lei Zhang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Xu Li
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yang Cheng
- The Key Laboratory of Monitoring and Management of Plant Diseases and Insects of Ministry of Agriculture and Rural Affairs, College of Plant Protection, Nanjing Agriculture University, Nanjing, 210095, China
| | - Dongming Wang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Changsheng Xu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Mengyi Qi
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jihong Wang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Xiangrui Guo
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Xianfeng Ye
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yan Huang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Danyu Shen
- The Key Laboratory of Monitoring and Management of Plant Diseases and Insects of Ministry of Agriculture and Rural Affairs, College of Plant Protection, Nanjing Agriculture University, Nanjing, 210095, China
| | - Daolong Dou
- The Key Laboratory of Monitoring and Management of Plant Diseases and Insects of Ministry of Agriculture and Rural Affairs, College of Plant Protection, Nanjing Agriculture University, Nanjing, 210095, China
- Academy for Advanced Interdisciplinary Studies, Nanjing Agricultural University, Nanjing, 210095, China
| | - Hui Cao
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Zhoukun Li
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
| | - Zhongli Cui
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
- Academy for Advanced Interdisciplinary Studies, Nanjing Agricultural University, Nanjing, 210095, China.
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3
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Edwards KA, Randall EA, Wolfe PC, Angert ER, Kraft CE. Dietary factors potentially impacting thiaminase I-mediated thiamine deficiency. Sci Rep 2023; 13:7008. [PMID: 37117240 PMCID: PMC10147936 DOI: 10.1038/s41598-023-34063-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 04/24/2023] [Indexed: 04/30/2023] Open
Abstract
Fish population declines from thiamine (vitamin B1) deficiency have been widespread in ecologically and economically valuable organisms, ranging from the Great Lakes to the Baltic Sea and, most recently, the California coast. Thiamine deficiencies in predatory fishes are often attributed to a diet of prey fishes with high levels of thiamine-degrading (e.g., thiaminase) enzymes, such as alewives, rainbow smelt, and anchovies. Since their discovery, thiaminase I enzymes have been recognized for breaking down thiamine into its pyrimidine and thiazole moieties using various nucleophilic co-substrates to afford cleavage, but these studies have not thoroughly considered other factors that could modify enzyme activity. We found the thiaminase I enzyme from Clostridium botulinum efficiently degrades thiamine in the presence of pyridoxine (vitamin B6) as a co-substrate but has relatively limited activity in the presence of nicotinic acid (vitamin B3). Using fluorescence measurements, thiamine degradation in an over-the-counter complete multivitamin formulation was inhibited, and a B-complex formulation required co-substrate supplementation for maximal thiamine depletion. These studies prompted the evaluation of specific constituents contributing to thiaminase I inhibition by both chromatography and fluorescence assays: Cu2+ potently and irreversibly inhibited thiamine degradation; ascorbic acid was a strong but reversible inhibitor; Fe2+, Mn2+ and Fe3+ modulated thiamine degradation to a lesser degree. The enhancement by pyridoxine and inhibition by Cu2+ extended to thiaminase-mediated degradation from Burkholderia thailandensis, Paenibacillus thiaminolyticus, and Paenibacillus apiarius in tryptic soy broth supernatants. These co-substrate limitations and the common presence of inhibitory dietary factors complement recent studies reporting that the intended function of thiaminase enzymes is to recycle thiamine breakdown products for thiamine synthesis, not thiamine degradation.
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Affiliation(s)
- Katie A Edwards
- Department of Pharmaceutical Sciences, Binghamton University, Binghamton, NY, 13902, USA.
- Department of Microbiology, Cornell University, Ithaca, NY, 14853, USA.
| | - Eileen A Randall
- Department of Natural Resources and the Environment, Cornell University, Ithaca, NY, 14853, USA
| | - Patricia C Wolfe
- Department of Pharmaceutical Sciences, Binghamton University, Binghamton, NY, 13902, USA
| | - Esther R Angert
- Department of Microbiology, Cornell University, Ithaca, NY, 14853, USA
| | - Clifford E Kraft
- Department of Natural Resources and the Environment, Cornell University, Ithaca, NY, 14853, USA
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4
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Richter CA, Evans AN, Heppell SA, Zajicek JL, Tillitt DE. Genetic basis of thiaminase I activity in a vertebrate, zebrafish Danio rerio. Sci Rep 2023; 13:698. [PMID: 36639393 PMCID: PMC9839694 DOI: 10.1038/s41598-023-27612-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 01/04/2023] [Indexed: 01/15/2023] Open
Abstract
Thiamine (vitamin B1) metabolism is an important driver of human and animal health and ecological functioning. Some organisms, including species of ferns, mollusks, and fish, contain thiamine-degrading enzymes known as thiaminases, and consumption of these organisms can lead to thiamine deficiency in the consumer. Consumption of fish containing thiaminase has led to elevated mortality and recruitment failure in farmed animals and wild salmonine populations around the world. In the North American Great Lakes, consumption of the non-native prey fish alewife (Alosa pseudoharengus) by native lake trout (Salvelinus namaycush) led to thiamine deficiency in the trout, contributed to elevated fry mortality, and impeded natural population recruitment. Several thiaminases have been genetically characterized in bacteria and unicellular eukaryotes, and the source of thiaminase in multicellular organisms has been hypothesized to be gut microflora. In an unexpected discovery, we identified thiaminase I genes in zebrafish (Danio rerio) with homology to bacterial tenA thiaminase II. The biochemical activity of zebrafish thiaminase I (GenBank NP_001314821.1) was confirmed in a recombinant system. Genes homologous to the zebrafish tenA-like thiaminase I were identified in many animals, including common carp (Cyprinus carpio), zebra mussel (Dreissena polymorpha) and alewife. Thus, the source of thiaminase I in alewife impacting lake trout populations is likely to be de novo synthesis.
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Affiliation(s)
- Catherine A Richter
- U.S. Geological Survey, Columbia Environmental Research Center, Columbia, MO, 65201, USA.
| | - Allison N Evans
- Department of Fisheries, Wildlife, and Conservation Sciences, Oregon State University, Corvallis, OR, 97331, USA.,Department of Microbiology, Oregon State University, Corvallis, OR, 97331, USA
| | - Scott A Heppell
- Department of Fisheries, Wildlife, and Conservation Sciences, Oregon State University, Corvallis, OR, 97331, USA
| | - James L Zajicek
- U.S. Geological Survey, Columbia Environmental Research Center, Columbia, MO, 65201, USA
| | - Donald E Tillitt
- U.S. Geological Survey, Columbia Environmental Research Center, Columbia, MO, 65201, USA
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5
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Prasad A, Breithaupt C, Nguyen DA, Lilie H, Ziegler J, Stubbs MT. Mechanism of chorismate dehydratase MqnA, the first enzyme of the futalosine pathway, proceeds via substrate-assisted catalysis. J Biol Chem 2022; 298:102601. [PMID: 36265588 PMCID: PMC9672406 DOI: 10.1016/j.jbc.2022.102601] [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: 05/05/2022] [Revised: 10/10/2022] [Accepted: 10/12/2022] [Indexed: 11/07/2022] Open
Abstract
MqnA, the only chorismate dehydratase known so far, catalyzes the initial step in the biosynthesis of menaquinone via the futalosine pathway. Details of the MqnA reaction mechanism remain unclear. Here, we present crystal structures of Streptomyces coelicolor MqnA and its active site mutants in complex with chorismate and the product 3-enolpyruvyl-benzoate, produced during heterologous expression in Escherichia coli. Together with activity studies, our data are in line with dehydration proceeding via substrate assisted catalysis, with the enol pyruvyl group of chorismate acting as catalytic base. Surprisingly, structures of the mutant Asn17Asp with copurified ligand suggest that the enzyme converts to a hydrolase by serendipitous positioning of the carboxyl group. All complex structures presented here exhibit a closed Venus flytrap fold, with the enzyme exploiting the characteristic ligand binding properties of the fold for specific substrate binding and catalysis. The conformational rearrangements that facilitate complete burial of substrate/product, with accompanying topological changes to the enzyme surface, could foster substrate channeling within the biosynthetic pathway.
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Affiliation(s)
- Archna Prasad
- Institut für Biochemie und Biotechnologie, Charles-Tanford-Proteinzentrum, Martin-Luther-Universität – Halle-Wittenberg, Halle/Saale, Germany
| | - Constanze Breithaupt
- Institut für Biochemie und Biotechnologie, Charles-Tanford-Proteinzentrum, Martin-Luther-Universität – Halle-Wittenberg, Halle/Saale, Germany
| | - Duc-Anh Nguyen
- Institut für Biochemie und Biotechnologie, Charles-Tanford-Proteinzentrum, Martin-Luther-Universität – Halle-Wittenberg, Halle/Saale, Germany
| | - Hauke Lilie
- Institut für Biochemie und Biotechnologie, Charles-Tanford-Proteinzentrum, Martin-Luther-Universität – Halle-Wittenberg, Halle/Saale, Germany
| | - Jörg Ziegler
- Abteilung Molekulare Signalverarbeitung, Leibniz-Institut für Pflanzenbiochemie, Halle/Saale, Germany
| | - Milton T. Stubbs
- Institut für Biochemie und Biotechnologie, Charles-Tanford-Proteinzentrum, Martin-Luther-Universität – Halle-Wittenberg, Halle/Saale, Germany,For correspondence: Milton T. Stubbs
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6
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Howe GW, Grenade NL. Sulfite-Catalyzed Nucleophilic Substitution Reactions with Thiamin and Analogous Pyrimidine Donors Proceed via an S NAE Mechanism. J Org Chem 2022; 87:13224-13235. [PMID: 36150085 DOI: 10.1021/acs.joc.2c01685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
When treated with SO32-, thiamin undergoes a substitution reaction to release a thiazole leaving group and the corresponding sulfonate. Although this reaction could proceed via a simple SN2-like mechanism, a multistep addition-elimination (SNAE) mechanism involving the addition of SO32- to C6' of the 4-aminopyrimidine of thiamin has also been proposed. Although this reaction has potential utility in the synthesis of substituted pyrimidines and provides a direct analogue to reactions catalyzed by thiaminases, a detailed mechanistic picture of the SO32--catalyzed cleavage of thiamin has remained elusive. Here, DFT calculations have been used to probe the relative energetics and the factors that shape the potential energy surfaces that define the possible mechanisms of substitution. These calculations provide clear support for the SNAE mechanism over an SN2-like process and illustrate that the unique ability of SO32- to activate thiamin toward nucleophilic displacement is due to the combined nucleophilicity and relatively poor leaving group ability of SO32-. Both of these factors favor the forward partitioning of the sulfite adduct toward the cleavage products whereas adducts formed with other nucleophiles overwhelmingly revert to reactants. Calculations performed with a range of substrates with various electrophilicities and nucleofugalities consistently suggest that the SNAE pathway is significantly lower in energy than the direct substitution, illustrating that this SO32--catalyzed multistep process is likely to be broadly applicable both in solution and in catalysis by thiaminases.
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Affiliation(s)
- Graeme W Howe
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario K7L 3N6, Canada
| | - Neil L Grenade
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario K7L 3N6, Canada
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7
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Edwards KA, Randall EA, Tu-Maung N, Sannino DR, Feder S, Angert ER, Kraft CE. Periplasmic binding protein-based magnetic isolation and detection of thiamine in complex biological matrices. Talanta 2019; 205:120168. [PMID: 31450459 DOI: 10.1016/j.talanta.2019.120168] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 07/19/2019] [Accepted: 07/21/2019] [Indexed: 11/19/2022]
Abstract
Deficiencies in thiamine (vitamin B1) cause a host of neurological and reproductive impairments yielding morbidity and mortality across environmental and clinical realms. In a technique analogous to immunomagnetic separation, we introduce the use of thiamine periplasmic binding protein (TBP)-conjugated magnetic beads to isolate thiamine from complex matrices. TBP expressed in Escherichia coli is highly specific to thiamine and provides an alternative to antibodies for this non-immunogenic target. After incubation with the sample and removal of unbound matrix constituents, thiamine is simultaneously released and converted to its fluorescent oxidation product thiochrome by alkaline potassium ferricyanide. Subsequent measurement of fluorescence at thiochrome-specific wavelengths provides a second layer of specificity for the detection of thiamine. Thiamine could be quantified at concentrations as low as 5 nM ranging up to 240 nM. Within, we apply this technique to selectively capture and quantify thiamine in complex salmonid fish egg and tissue matrices. Our results showed no measurable non-specific binding to the beads by endogenous fluorophores in the fish egg matrix. Thiamine levels as low as 0.2 nmol/g of fish egg can be detected using this approach, which is sufficient to assess deficiencies causing morbidity and mortality in fish that occur at 1.0 nmol/g of egg. This practical method may find application in other resource limited settings for clinical, food, or dietary supplement analyses.
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Affiliation(s)
- Katie A Edwards
- Department of Natural Resources, Fernow Hall, Cornell University, Ithaca, NY, 14853, USA; Department of Microbiology, Wing Hall, Cornell University, Ithaca, NY, 14853, USA; Department of Pharmaceutical Sciences, PO Box 6000, Binghamton University, Binghamton, NY, 13902, USA.
| | - Eileen A Randall
- Department of Natural Resources, Fernow Hall, Cornell University, Ithaca, NY, 14853, USA
| | - Nicole Tu-Maung
- Department of Natural Resources, Fernow Hall, Cornell University, Ithaca, NY, 14853, USA
| | - David R Sannino
- Department of Microbiology, Wing Hall, Cornell University, Ithaca, NY, 14853, USA
| | - Seth Feder
- Department of Natural Resources, Fernow Hall, Cornell University, Ithaca, NY, 14853, USA
| | - Esther R Angert
- Department of Microbiology, Wing Hall, Cornell University, Ithaca, NY, 14853, USA
| | - Clifford E Kraft
- Department of Natural Resources, Fernow Hall, Cornell University, Ithaca, NY, 14853, USA
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8
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Thiaminase I Provides a Growth Advantage by Salvaging Precursors from Environmental Thiamine and Its Analogs in Burkholderia thailandensis. Appl Environ Microbiol 2018. [PMID: 30006396 DOI: 10.1128/aem.01268-18)] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Thiamine is essential to life, as it serves as a cofactor for enzymes involved in critical carbon transformations. Many bacteria can synthesize thiamine, while thiamine auxotrophs must obtain it or its precursors from the environment. Thiaminases degrade thiamine by catalyzing the base-exchange substitution of thiazole with a nucleophile, and thiaminase I specifically has been implicated in thiamine deficiency syndromes in animals. The biological role of this secreted enzyme has been a long-standing mystery. We used the thiaminase I-producing soil bacterium Burkholderia thailandensis as a model to ascertain its function. First, we generated thiamine auxotrophs, which are still able to use exogenous precursors (thiazole and hydroxymethyl pyrimidine), to synthesize thiamine. We found that thiaminase I extended the survival of these strains, when grown in defined media where thiamine was serially diluted out, compared to isogenic strains that could not produce thiaminase I. Thiamine auxotrophs grew better on thiamine precursors than thiamine itself, suggesting thiaminase I functions to convert thiamine to useful precursors. Furthermore, our findings demonstrate that thiaminase I cleaves phosphorylated thiamine and toxic analogs, which releases precursors that can then be used for thiamine synthesis. This study establishes a biological role for this perplexing enzyme and provides additional insight into the complicated nature of thiamine metabolism and how individual bacteria may manipulate the availability of a vital nutrient in the environment.IMPORTANCE The function of thiaminase I has remained a long-standing, unsolved mystery. The enzyme is only known to be produced by a small subset of microorganisms, although thiaminase I activity has been associated with numerous plants and animals, and is implicated in thiamine deficiencies brought on by consumption of organisms containing this enzyme. Genomic and biochemical analyses have shed light on potential roles for the enzyme. Using the genetically amenable thiaminase I-producing soil bacterium Burkholderia thailandensis, we were able to demonstrate that thiaminase I helps salvage precursors from thiamine derivatives in the environment and degrades thiamine to its precursors, which are preferentially used by B. thailandensis auxotrophs. Our study establishes a biological role for this perplexing enzyme and provides insight into the complicated nature of thiamine metabolism. It also establishes B. thailandensis as a robust model system for studying thiamine metabolism.
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9
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Thiaminase I Provides a Growth Advantage by Salvaging Precursors from Environmental Thiamine and Its Analogs in Burkholderia thailandensis. Appl Environ Microbiol 2018; 84:AEM.01268-18. [PMID: 30006396 DOI: 10.1128/aem.01268-18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 07/03/2018] [Indexed: 12/14/2022] Open
Abstract
Thiamine is essential to life, as it serves as a cofactor for enzymes involved in critical carbon transformations. Many bacteria can synthesize thiamine, while thiamine auxotrophs must obtain it or its precursors from the environment. Thiaminases degrade thiamine by catalyzing the base-exchange substitution of thiazole with a nucleophile, and thiaminase I specifically has been implicated in thiamine deficiency syndromes in animals. The biological role of this secreted enzyme has been a long-standing mystery. We used the thiaminase I-producing soil bacterium Burkholderia thailandensis as a model to ascertain its function. First, we generated thiamine auxotrophs, which are still able to use exogenous precursors (thiazole and hydroxymethyl pyrimidine), to synthesize thiamine. We found that thiaminase I extended the survival of these strains, when grown in defined media where thiamine was serially diluted out, compared to isogenic strains that could not produce thiaminase I. Thiamine auxotrophs grew better on thiamine precursors than thiamine itself, suggesting thiaminase I functions to convert thiamine to useful precursors. Furthermore, our findings demonstrate that thiaminase I cleaves phosphorylated thiamine and toxic analogs, which releases precursors that can then be used for thiamine synthesis. This study establishes a biological role for this perplexing enzyme and provides additional insight into the complicated nature of thiamine metabolism and how individual bacteria may manipulate the availability of a vital nutrient in the environment.IMPORTANCE The function of thiaminase I has remained a long-standing, unsolved mystery. The enzyme is only known to be produced by a small subset of microorganisms, although thiaminase I activity has been associated with numerous plants and animals, and is implicated in thiamine deficiencies brought on by consumption of organisms containing this enzyme. Genomic and biochemical analyses have shed light on potential roles for the enzyme. Using the genetically amenable thiaminase I-producing soil bacterium Burkholderia thailandensis, we were able to demonstrate that thiaminase I helps salvage precursors from thiamine derivatives in the environment and degrades thiamine to its precursors, which are preferentially used by B. thailandensis auxotrophs. Our study establishes a biological role for this perplexing enzyme and provides insight into the complicated nature of thiamine metabolism. It also establishes B. thailandensis as a robust model system for studying thiamine metabolism.
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10
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Zhang K, Bian J, Deng Y, Smith A, Nunez RE, Li MB, Pal U, Yu AM, Qiu W, Ealick SE, Li C. Lyme disease spirochaete Borrelia burgdorferi does not require thiamin. Nat Microbiol 2016; 2:16213. [PMID: 27869793 DOI: 10.1038/nmicrobiol.2016.213] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 09/21/2016] [Indexed: 12/12/2022]
Abstract
Thiamin pyrophosphate (ThDP), the active form of thiamin (vitamin B1), is believed to be an essential cofactor for all living organisms1,2. Here, we report the unprecedented result that thiamin is dispensable for the growth of the Lyme disease pathogen Borrelia burgdorferi (Bb)3. Bb lacks genes for thiamin biosynthesis and transport as well as known ThDP-dependent enzymes4, and we were unable to detect thiamin or its derivatives in Bb cells. We showed that eliminating thiamin in vitro and in vivo using BcmE, an enzyme that degrades thiamin, has no impact on Bb growth and survival during its enzootic infectious cycle. Finally, high-performance liquid chromatography analysis reveals that the level of thiamin and its derivatives in Ixodes scapularis ticks, the enzootic vector of Bb, is extremely low. These results suggest that by dispensing with use of thiamin, Borrelia, and perhaps other tick-transmitted bacterial pathogens, are uniquely adapted to survive in tick vectors before transmitting to mammalian hosts. To our knowledge, such a mechanism has not been reported previously in any living organisms.
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Affiliation(s)
- Kai Zhang
- Department of Oral Biology, State University of New York at Buffalo, Buffalo, New York 14214, USA
| | - Jiang Bian
- Department of Oral Biology, State University of New York at Buffalo, Buffalo, New York 14214, USA
| | - Yijie Deng
- Department of Oral Biology, State University of New York at Buffalo, Buffalo, New York 14214, USA
| | - Alexis Smith
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland 20742, USA
| | - Roy E Nunez
- Department of Biological Sciences, The City University of New York, New York, New York 10021, USA
| | - Michael B Li
- Department of Oral Biology, State University of New York at Buffalo, Buffalo, New York 14214, USA
| | - Utpal Pal
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland 20742, USA
| | - Ai-Ming Yu
- Department of Biochemistry &Molecular Medicine, UC Davis School of Medicine, Sacramento, California 95817, USA
| | - Weigang Qiu
- Department of Biological Sciences, The City University of New York, New York, New York 10021, USA
| | - Steven E Ealick
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA
| | - Chunhao Li
- Department of Oral Biology, State University of New York at Buffalo, Buffalo, New York 14214, USA.,Department of Microbiology and Immunology, State University of New York at Buffalo, Buffalo, New York 14214, USA
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11
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Fitzpatrick TB, Thore S. Complex behavior: from cannibalism to suicide in the vitamin B1 biosynthesis world. Curr Opin Struct Biol 2014; 29:34-43. [DOI: 10.1016/j.sbi.2014.08.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 08/27/2014] [Accepted: 08/28/2014] [Indexed: 10/24/2022]
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12
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Cooper LE, O'Leary SE, Begley TP. Biosynthesis of a thiamin antivitamin in Clostridium botulinum. Biochemistry 2014; 53:2215-7. [PMID: 24654570 PMCID: PMC4004229 DOI: 10.1021/bi500281a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Bacimethrin-derived
2′-methoxythiamin pyrophosphate inhibits
microbial growth by disrupting metabolic pathways dependent on thiamin-utilizing
enzymes. This study describes the discovery of the bacimethrin biosynthetic
gene cluster of Clostridium botulinum A ATCC 19397
and in vitro reconstitution of bacimethrin biosynthesis
from cytidine 5′-monophosphate.
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Affiliation(s)
- Lisa E Cooper
- Department of Chemistry, Texas A&M University , College Station, Texas 77842, United States
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