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Bazurto JV, Nayak DD, Ticak T, Davlieva M, Lee JA, Hellenbrand CN, Lambert LB, Benski OJ, Quates CJ, Johnson JL, Patel JS, Ytreberg FM, Shamoo Y, Marx CJ. EfgA is a conserved formaldehyde sensor that leads to bacterial growth arrest in response to elevated formaldehyde. PLoS Biol 2021; 19:e3001208. [PMID: 34038406 PMCID: PMC8153426 DOI: 10.1371/journal.pbio.3001208] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 03/25/2021] [Indexed: 01/07/2023] Open
Abstract
Normal cellular processes give rise to toxic metabolites that cells must mitigate. Formaldehyde is a universal stressor and potent metabolic toxin that is generated in organisms from bacteria to humans. Methylotrophic bacteria such as Methylorubrum extorquens face an acute challenge due to their production of formaldehyde as an obligate central intermediate of single-carbon metabolism. Mechanisms to sense and respond to formaldehyde were speculated to exist in methylotrophs for decades but had never been discovered. Here, we identify a member of the DUF336 domain family, named efgA for enhanced formaldehyde growth, that plays an important role in endogenous formaldehyde stress response in M. extorquens PA1 and is found almost exclusively in methylotrophic taxa. Our experimental analyses reveal that EfgA is a formaldehyde sensor that rapidly arrests growth in response to elevated levels of formaldehyde. Heterologous expression of EfgA in Escherichia coli increases formaldehyde resistance, indicating that its interaction partners are widespread and conserved. EfgA represents the first example of a formaldehyde stress response system that does not involve enzymatic detoxification. Thus, EfgA comprises a unique stress response mechanism in bacteria, whereby a single protein directly senses elevated levels of a toxic intracellular metabolite and safeguards cells from potential damage.
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Affiliation(s)
- Jannell V. Bazurto
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, Idaho, United States of America
- Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, Idaho, United States of America
- Department of Plant and Microbial Biology, University of Minnesota, Twin Cities, Minnesota, United States of America
- Microbial and Plant Genomics Institute, University of Minnesota, Twin Cities, Minnesota, United States of America
- Biotechnology Institute, University of Minnesota, Twin Cities, Minnesota, United States of America
- * E-mail: (JVB); (CJM)
| | - Dipti D. Nayak
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, United States of America
- Department of Microbiology, University of Illinois, Urbana, Illinois, United States of America
| | - Tomislav Ticak
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, Idaho, United States of America
- Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, Idaho, United States of America
| | - Milya Davlieva
- Department of Biosciences, Rice University, Houston, Texas, United States of America
| | - Jessica A. Lee
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, Idaho, United States of America
- Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, Idaho, United States of America
- Space Biosciences Research Branch, NASA Ames Research Center, Moffett Field, California, United States of America
| | - Chandler N. Hellenbrand
- Department of Plant and Microbial Biology, University of Minnesota, Twin Cities, Minnesota, United States of America
| | - Leah B. Lambert
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Olivia J. Benski
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Caleb J. Quates
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, Idaho, United States of America
| | - Jill L. Johnson
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, Idaho, United States of America
- Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, Idaho, United States of America
| | - Jagdish Suresh Patel
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, Idaho, United States of America
| | - F. Marty Ytreberg
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, Idaho, United States of America
- Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, Idaho, United States of America
- Department of Physics, University of Idaho, Moscow, Idaho, United States of America
| | - Yousif Shamoo
- Department of Biosciences, Rice University, Houston, Texas, United States of America
| | - Christopher J. Marx
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, Idaho, United States of America
- Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, Idaho, United States of America
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, United States of America
- * E-mail: (JVB); (CJM)
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Formaldehyde-responsive proteins, TtmR and EfgA, reveal a tradeoff between formaldehyde resistance and efficient transition to methylotrophy in Methylorubrum extorquens. J Bacteriol 2021; 203:JB.00589-20. [PMID: 33619153 PMCID: PMC8092166 DOI: 10.1128/jb.00589-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
For bacteria to thrive they must be well-adapted to their environmental niche, which may involve specialized metabolism, timely adaptation to shifting environments, and/or the ability to mitigate numerous stressors. These attributes are highly dependent on cellular machinery that can sense both the external and intracellular environment. Methylorubrum extorquens is an extensively studied facultative methylotroph, an organism that can use single-carbon compounds as their sole source of carbon and energy. In methylotrophic metabolism, carbon flows through formaldehyde as a central metabolite; thus, formaldehyde is both an obligate metabolite and a metabolic stressor. Via the one-carbon dissimilation pathway, free formaldehyde is rapidly incorporated by formaldehyde activating enzyme (Fae), which is constitutively expressed at high levels. In the presence of elevated formaldehyde levels, a recently identified formaldehyde-sensing protein, EfgA, induces growth arrest. Herein, we describe TtmR, a formaldehyde-responsive transcription factor that, like EfgA, modulates formaldehyde resistance. TtmR is a member of the MarR family of transcription factors and impacts the expression of 75 genes distributed throughout the genome, many of which are transcription factors and/or involved in stress response, including efgA Notably, when M. extorquens is adapting its metabolic network during the transition to methylotrophy, efgA and ttmR mutants experience an imbalance in formaldehyde production and a notable growth delay. Although methylotrophy necessitates that M. extorquens maintain a relatively high level of formaldehyde tolerance, this work reveals a tradeoff between formaldehyde resistance and the efficient transition to methylotrophic growth and suggests that TtmR and EfgA play a pivotal role in maintaining this balance.Importance: All organisms produce formaldehyde as a byproduct of enzymatic reactions and as a degradation product of metabolites. The ubiquity of formaldehyde in cellular biology suggests all organisms have evolved mechanisms of mitigating formaldehyde toxicity. However, formaldehyde-sensing is poorly described and prevention of formaldehyde-induced damage is primarily understood in the context of detoxification. Here we use an organism that is regularly exposed to elevated intracellular formaldehyde concentrations through high-flux one-carbon utilization pathways to gain insight into the role of formaldehyde-responsive proteins that modulate formaldehyde resistance. Using a combination of genetic and transcriptomic analyses, we identify dozens of genes putatively involved in formaldehyde resistance, determined the relationship between two different formaldehyde response systems and identified an inherent tradeoff between formaldehyde resistance and optimal transition to methylotrophic metabolism.
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Bazurto JV, Riazi S, D’Alton S, Deatherage DE, Bruger EL, Barrick JE, Marx CJ. Global Transcriptional Response of Methylorubrum extorquens to Formaldehyde Stress Expands the Role of EfgA and Is Distinct from Antibiotic Translational Inhibition. Microorganisms 2021; 9:347. [PMID: 33578755 PMCID: PMC7916467 DOI: 10.3390/microorganisms9020347] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 02/07/2021] [Accepted: 02/08/2021] [Indexed: 11/16/2022] Open
Abstract
The potency and indiscriminate nature of formaldehyde reactivity upon biological molecules make it a universal stressor. However, some organisms such as Methylorubrum extorquens possess means to rapidly and effectively mitigate formaldehyde-induced damage. EfgA is a recently identified formaldehyde sensor predicted to halt translation in response to elevated formaldehyde as a means to protect cells. Herein, we investigate growth and changes in gene expression to understand how M. extorquens responds to formaldehyde with and without the EfgA-formaldehyde-mediated translational response, and how this mechanism compares to antibiotic-mediated translation inhibition. These distinct mechanisms of translation inhibition have notable differences: they each involve different specific players and in addition, formaldehyde also acts as a general, multi-target stressor and a potential carbon source. We present findings demonstrating that in addition to its characterized impact on translation, functional EfgA allows for a rapid and robust transcriptional response to formaldehyde and that removal of EfgA leads to heightened proteotoxic and genotoxic stress in the presence of increased formaldehyde levels. We also found that many downstream consequences of translation inhibition were shared by EfgA-formaldehyde- and kanamycin-mediated translation inhibition. Our work uncovered additional layers of regulatory control enacted by functional EfgA upon experiencing formaldehyde stress, and further demonstrated the importance this protein plays at both transcriptional and translational levels in this model methylotroph.
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Affiliation(s)
- Jannell V. Bazurto
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA; (J.V.B.); (S.R.); (E.L.B.)
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, ID 83844, USA
- Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, ID 83844, USA
- Department of Plant and Microbial Biology, University of Minnesota, Twin Cities, MN 55108, USA
- Microbial and Plant Genomics Institute, University of Minnesota, Twin Cities, MN 55108, USA
- Biotechnology Institute, University of Minnesota, Twin Cities, MN 55108, USA
| | - Siavash Riazi
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA; (J.V.B.); (S.R.); (E.L.B.)
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, ID 83844, USA
- Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, ID 83844, USA
| | - Simon D’Alton
- Center for Systems and Synthetic Biology, Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; (S.D.); (D.E.D.); (J.E.B.)
| | - Daniel E. Deatherage
- Center for Systems and Synthetic Biology, Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; (S.D.); (D.E.D.); (J.E.B.)
| | - Eric L. Bruger
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA; (J.V.B.); (S.R.); (E.L.B.)
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, ID 83844, USA
- Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, ID 83844, USA
| | - Jeffrey E. Barrick
- Center for Systems and Synthetic Biology, Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; (S.D.); (D.E.D.); (J.E.B.)
| | - Christopher J. Marx
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA; (J.V.B.); (S.R.); (E.L.B.)
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, ID 83844, USA
- Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, ID 83844, USA
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Yanpirat P, Nakatsuji Y, Hiraga S, Fujitani Y, Izumi T, Masuda S, Mitsui R, Nakagawa T, Tani A. Lanthanide-Dependent Methanol and Formaldehyde Oxidation in Methylobacterium aquaticum Strain 22A. Microorganisms 2020; 8:microorganisms8060822. [PMID: 32486139 PMCID: PMC7356819 DOI: 10.3390/microorganisms8060822] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 05/26/2020] [Accepted: 05/28/2020] [Indexed: 01/06/2023] Open
Abstract
Lanthanides (Ln) are an essential cofactor for XoxF-type methanol dehydrogenases (MDHs) in Gram-negative methylotrophs. The Ln3+ dependency of XoxF has expanded knowledge and raised new questions in methylotrophy, including the differences in characteristics of XoxF-type MDHs, their regulation, and the methylotrophic metabolism including formaldehyde oxidation. In this study, we genetically identified one set of Ln3+- and Ca2+-dependent MDHs (XoxF1 and MxaFI), that are involved in methylotrophy, and an ExaF-type Ln3+-dependent ethanol dehydrogenase, among six MDH-like genes in Methylobacterium aquaticum strain 22A. We also identified the causative mutations in MxbD, a sensor kinase necessary for mxaF expression and xoxF1 repression, for suppressive phenotypes in xoxF1 mutants defective in methanol growth even in the absence of Ln3+. Furthermore, we examined the phenotypes of a series of formaldehyde oxidation-pathway mutants (fae1, fae2, mch in the tetrahydromethanopterin (H4MPT) pathway and hgd in the glutathione-dependent formaldehyde dehydrogenase (GSH) pathway). We found that MxaF produces formaldehyde to a toxic level in the absence of the formaldehyde oxidation pathways and that either XoxF1 or ExaF can oxidize formaldehyde to alleviate formaldehyde toxicity in vivo. Furthermore, the GSH pathway has a supportive role for the net formaldehyde oxidation in addition to the H4MPT pathway that has primary importance. Studies on methylotrophy in Methylobacterium species have a long history, and this study provides further insights into genetic and physiological diversity and the differences in methylotrophy within the plant-colonizing methylotrophs.
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Affiliation(s)
- Patcha Yanpirat
- Institute of Plant Science and Resources, Okayama University, Okayama 710-0046, Japan; (P.Y.); (Y.N.); (S.H.); (Y.F.); (T.I.); (S.M.)
| | - Yukari Nakatsuji
- Institute of Plant Science and Resources, Okayama University, Okayama 710-0046, Japan; (P.Y.); (Y.N.); (S.H.); (Y.F.); (T.I.); (S.M.)
| | - Shota Hiraga
- Institute of Plant Science and Resources, Okayama University, Okayama 710-0046, Japan; (P.Y.); (Y.N.); (S.H.); (Y.F.); (T.I.); (S.M.)
| | - Yoshiko Fujitani
- Institute of Plant Science and Resources, Okayama University, Okayama 710-0046, Japan; (P.Y.); (Y.N.); (S.H.); (Y.F.); (T.I.); (S.M.)
| | - Terumi Izumi
- Institute of Plant Science and Resources, Okayama University, Okayama 710-0046, Japan; (P.Y.); (Y.N.); (S.H.); (Y.F.); (T.I.); (S.M.)
| | - Sachiko Masuda
- Institute of Plant Science and Resources, Okayama University, Okayama 710-0046, Japan; (P.Y.); (Y.N.); (S.H.); (Y.F.); (T.I.); (S.M.)
- Advanced Low Carbon Technology Research and Development Program, Japan Science and Technology Agency, Tokyo 102-0076, Japan
- RIKEN Center for Sustainable Resource Science, Kanagawa 230-0045, Japan
| | - Ryoji Mitsui
- Department of Biochemistry, Faculty of Science, Okayama University of Science, Okayama 700-8530, Japan;
| | - Tomoyuki Nakagawa
- The United Graduate School of Agricultural Science, Gifu University, Gifu 501-1193, Japan;
- The Graduate School of Natural Sciences and Technologies, Gifu University, Gifu 501-1193, Japan
| | - Akio Tani
- Institute of Plant Science and Resources, Okayama University, Okayama 710-0046, Japan; (P.Y.); (Y.N.); (S.H.); (Y.F.); (T.I.); (S.M.)
- Correspondence:
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Lim CK, Villada JC, Chalifour A, Duran MF, Lu H, Lee PKH. Designing and Engineering Methylorubrum extorquens AM1 for Itaconic Acid Production. Front Microbiol 2019; 10:1027. [PMID: 31143170 PMCID: PMC6520949 DOI: 10.3389/fmicb.2019.01027] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 04/24/2019] [Indexed: 01/05/2023] Open
Abstract
Methylorubrum extorquens (formerly Methylobacterium extorquens) AM1 is a methylotrophic bacterium with a versatile lifestyle. Various carbon sources including acetate, succinate and methanol are utilized by M. extorquens AM1 with the latter being a promising inexpensive substrate for use in the biotechnology industry. Itaconic acid (ITA) is a high-value building block widely used in various industries. Given that no wildtype methylotrophic bacteria are able to utilize methanol to produce ITA, we tested the potential of M. extorquens AM1 as an engineered host for this purpose. In this study, we successfully engineered M. extorquens AM1 to express a heterologous codon-optimized gene encoding cis-aconitic acid decarboxylase. The engineered strain produced ITA using acetate, succinate and methanol as the carbon feedstock. The highest ITA titer in batch culture with methanol as the carbon source was 31.6 ± 5.5 mg/L, while the titer and productivity were 5.4 ± 0.2 mg/L and 0.056 ± 0.002 mg/L/h, respectively, in a scaled-up fed-batch bioreactor under 60% dissolved oxygen saturation. We attempted to enhance the carbon flux toward ITA production by impeding poly-β-hydroxybutyrate accumulation, which is used as carbon and energy storage, via mutation of the regulator gene phaR. Unexpectedly, ITA production by the phaR mutant strain was not higher even though poly-β-hydroxybutyrate concentration was lower. Genome-wide transcriptomic analysis revealed that phaR mutation in the ITA-producing strain led to complex rewiring of gene transcription, which might result in a reduced carbon flux toward ITA production. Besides poly-β-hydroxybutyrate metabolism, we found evidence that PhaR might regulate the transcription of many other genes including those encoding other regulatory proteins, methanol dehydrogenases, formate dehydrogenases, malate:quinone oxidoreductase, and those synthesizing pyrroloquinoline quinone and thiamine co-factors. Overall, M. extorquens AM1 was successfully engineered to produce ITA using acetate, succinate and methanol as feedstock, further supporting this bacterium as a feasible host for use in the biotechnology industry. This study showed that PhaR could have a broader regulatory role than previously anticipated, and increased our knowledge of this regulator and its influence on the physiology of M. extorquens AM1.
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Affiliation(s)
- Chee Kent Lim
- School of Energy and Environment, City University of Hong Kong, Hong Kong, China
| | - Juan C Villada
- School of Energy and Environment, City University of Hong Kong, Hong Kong, China
| | - Annie Chalifour
- Department of Chemistry, City University of Hong Kong, Hong Kong, China
| | - Maria F Duran
- School of Energy and Environment, City University of Hong Kong, Hong Kong, China
| | - Hongyuan Lu
- School of Energy and Environment, City University of Hong Kong, Hong Kong, China
| | - Patrick K H Lee
- School of Energy and Environment, City University of Hong Kong, Hong Kong, China
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