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Zmuda AJ, Kang X, Wissbroecker KB, Freund Saxhaug K, Costa KC, Hegeman AD, Niehaus TD. A universal metabolite repair enzyme removes a strong inhibitor of the TCA cycle. Nat Commun 2024; 15:846. [PMID: 38287013 PMCID: PMC10825186 DOI: 10.1038/s41467-024-45134-0] [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: 08/22/2023] [Accepted: 01/16/2024] [Indexed: 01/31/2024] Open
Abstract
A prevalent side-reaction of succinate dehydrogenase oxidizes malate to enol-oxaloacetate (OAA), a metabolically inactive form of OAA that is a strong inhibitor of succinate dehydrogenase. We purified from cow heart mitochondria an enzyme (OAT1) with OAA tautomerase (OAT) activity that converts enol-OAA to the physiological keto-OAA form, and determined that it belongs to the highly conserved and previously uncharacterized Fumarylacetoacetate_hydrolase_domain-containing protein family. From all three domains of life, heterologously expressed proteins were shown to have strong OAT activity, and ablating the OAT1 homolog caused significant growth defects. In Escherichia coli, expression of succinate dehydrogenase was necessary for OAT1-associated growth defects to occur, and ablating OAT1 caused a significant increase in acetate and other metabolites associated with anaerobic respiration. OAT1 increased the succinate dehydrogenase reaction rate by 35% in in vitro assays with physiological concentrations of both succinate and malate. Our results suggest that OAT1 is a universal metabolite repair enzyme that is required to maximize aerobic respiration efficiency by preventing succinate dehydrogenase inhibition.
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Affiliation(s)
- Anthony J Zmuda
- Department of Plant and Microbial Biology, University of Minnesota, Twin Cities, Saint Paul, MN, 55108, USA
| | - Xiaojun Kang
- Department of Plant and Microbial Biology, University of Minnesota, Twin Cities, Saint Paul, MN, 55108, USA
| | - Katie B Wissbroecker
- Department of Plant and Microbial Biology, University of Minnesota, Twin Cities, Saint Paul, MN, 55108, USA
| | - Katrina Freund Saxhaug
- Department of Horticultural Science, University of Minnesota, Twin Cities, Saint Paul, MN, 55108, USA
| | - Kyle C Costa
- Department of Plant and Microbial Biology, University of Minnesota, Twin Cities, Saint Paul, MN, 55108, USA
| | - Adrian D Hegeman
- Department of Plant and Microbial Biology, University of Minnesota, Twin Cities, Saint Paul, MN, 55108, USA
- Department of Horticultural Science, University of Minnesota, Twin Cities, Saint Paul, MN, 55108, USA
| | - Thomas D Niehaus
- Department of Plant and Microbial Biology, University of Minnesota, Twin Cities, Saint Paul, MN, 55108, USA.
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Guo T, Sperber AM, Krieger IV, Duan Y, Chemelewski VR, Sacchettini JC, Herman JK. Bacillus subtilis YisK possesses oxaloacetate decarboxylase activity and exhibits Mbl-dependent localization. J Bacteriol 2024; 206:e0020223. [PMID: 38047707 PMCID: PMC10810218 DOI: 10.1128/jb.00202-23] [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: 06/28/2023] [Accepted: 11/10/2023] [Indexed: 12/05/2023] Open
Abstract
YisK is an uncharacterized protein in Bacillus subtilis previously shown to interact genetically with the elongasome protein Mbl. YisK overexpression leads to cell widening and lysis, phenotypes that are dependent on mbl and suppressed by mbl mutations. In the present work, we characterize YisK's localization, structure, and enzymatic activity. We show that YisK localizes as puncta that depend on Mbl. YisK belongs to the fumarylacetoacetate hydrolase (FAH) superfamily, and crystal structures revealed close structural similarity to two oxaloacetate (OAA) decarboxylases: human mitochondrial FAHD1 and Corynebacterium glutamicum Cg1458. We demonstrate that YisK can also catalyze the decarboxylation of OAA (K m = 134 µM, K cat = 31 min-1). A catalytic dead variant (YisK E148A, E150A) retains wild-type localization and still widens cells following overexpression, indicating these activities are not dependent on YisK catalysis. Conversely, a non-localizing variant (YisK E30A) retains wild-type enzymatic activity in vitro but localizes diffusely and no longer widens cells following overexpression. Together, these results suggest that YisK may be subject to spatial regulation that depends on the cell envelope synthesis machinery. IMPORTANCE The elongasome is a multiprotein complex that guides lengthwise growth in some bacteria. We previously showed that, in B. subtilis, overexpression of an uncharacterized putative enzyme (YisK) perturbed function of the actin-like elongasome protein Mbl. Here, we show that YisK exhibits Mbl-dependent localization. Through biochemical and structural characterization, we demonstrate that, like its mitochondrial homolog FAHD1, YisK can catalyze the decarboxylation of the oxaloacetate to pyruvate and CO2. YisK is the first example of an enzyme implicated in central carbon metabolism with subcellular localization that depends on Mbl.
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Affiliation(s)
- Tingfeng Guo
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA
| | - Anthony M. Sperber
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA
| | - Inna V. Krieger
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA
| | - Yi Duan
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA
| | - Veronica R. Chemelewski
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA
| | - James C. Sacchettini
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA
- Department of Chemistry, Texas A&M University, College Station, Texas, USA
| | - Jennifer K. Herman
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA
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Qian J, Wang Y, Hu Z, Shi T, Wang Y, Ye C, Huang H. Bacillus sp. as a microbial cell factory: Advancements and future prospects. Biotechnol Adv 2023; 69:108278. [PMID: 37898328 DOI: 10.1016/j.biotechadv.2023.108278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 09/27/2023] [Accepted: 10/25/2023] [Indexed: 10/30/2023]
Abstract
Bacillus sp. is one of the most distinctive gram-positive bacteria, able to grow efficiently using cheap carbon sources and secrete a variety of useful substances, which are widely used in food, pharmaceutical, agricultural and environmental industries. At the same time, Bacillus sp. is also recognized as a safe genus with a relatively clear genetic background, which is conducive to the industrial production of target metabolites. In this review, we discuss the reasons why Bacillus sp. has been so extensively studied and summarize its advances in systems and synthetic biology, engineering strategies to improve microbial cell properties, and industrial applications in several metabolic engineering applications. Finally, we present the current challenges and possible solutions to provide a reliable basis for Bacillus sp. as a microbial cell factory.
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Affiliation(s)
- Jinyi Qian
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, PR China
| | - Yuzhou Wang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, PR China
| | - Zijian Hu
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, PR China
| | - Tianqiong Shi
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, PR China.
| | - Yuetong Wang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, PR China.
| | - Chao Ye
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, PR China.
| | - He Huang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, PR China.
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4
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Guan P, Chang Y, Li S, Wang X, Dong Z, Zhou W, Zheng Q, Huang Z, Suo B. Transcriptome analysis reveals the molecular mechanism of cinnamaldehyde against Bacillus cereus spores in ready-to-eat beef. Food Res Int 2023; 163:112185. [PMID: 36596126 DOI: 10.1016/j.foodres.2022.112185] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 11/04/2022] [Accepted: 11/15/2022] [Indexed: 11/21/2022]
Abstract
The purpose of this study was to investigate the antibacterial effect and mechanism of cinnamaldehyde on Bacillus cereus spores in ready-to-eat beef. The colour difference and texture of the ready-to-eat beef supplemented with cinnamaldehyde did not differ greatly from the colour and texture of the blank beef. However, cinnamaldehyde has an effective antibacterial effect on the total number of bacterial colonies and B. cereus spores in ready-to-eat beef. Transmission electron microscopy (TEM) analysis revealed that the cell membrane of B. cereus was disrupted by cinnamaldehyde, leading to leakage of intracellular components. Transcriptome sequencing (RNA-seq) indicated that the B. cereus spore resistance regulation system (sigB, sigW, rsbW, rsbV, yfkM and yflT) and phosphoenolpyruvate phosphotransferase system (PTS) (ptsH, ptsI and ptsG) respond positively to cinnamaldehyde in an adverse environment. Intracellular disorders due to damage to the cell membrane involve some transporters (copA, opuBA and opuD) and some oxidative stress systems (ywrO, scdA and katE) in the regulation of the body. However, downregulation of K+ transport channels (kdpD and kdpB), osmotic pressure regulation (opuE) and some oxidative stress (norR and srrA)-related genes may accelerate spore apoptosis. In addition, cinnamaldehyde also effectively inhibits the spore germination-related genes (smc, mreB and gerE). This study provides new insights into the molecular mechanism of the antibacterial effect of cinnamaldehyde on B. cereus spores in ready-to-eat beef.
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Affiliation(s)
- Peng Guan
- College of Food Science and Technology, Henan Agricultural University, Zhengzhou, China
| | - Yuting Chang
- College of Food Science and Technology, Henan Agricultural University, Zhengzhou, China
| | - Sen Li
- College of Food Science and Technology, Henan Agricultural University, Zhengzhou, China
| | - Xiaojie Wang
- College of Food Science and Technology, Henan Agricultural University, Zhengzhou, China; Key Laboratory of Staple Grain Processing, Ministry of Agriculture and Rural Affairs, Zhengzhou, China; National R&D Center for Frozen Rice & Wheat Products Processing Technology, Henan Engineering Laboratory of Quick-Frozen Flour-Rice Food and Prepared Food, Henan Agricultural University, Zhengzhou, China
| | - Zijie Dong
- College of Food Science and Technology, Henan Agricultural University, Zhengzhou, China
| | - Weitao Zhou
- College of Food Science and Technology, Henan Agricultural University, Zhengzhou, China
| | - Qi Zheng
- College of Food Science and Technology, Henan Agricultural University, Zhengzhou, China
| | - Zhongmin Huang
- College of Food Science and Technology, Henan Agricultural University, Zhengzhou, China; Key Laboratory of Staple Grain Processing, Ministry of Agriculture and Rural Affairs, Zhengzhou, China; National R&D Center for Frozen Rice & Wheat Products Processing Technology, Henan Engineering Laboratory of Quick-Frozen Flour-Rice Food and Prepared Food, Henan Agricultural University, Zhengzhou, China
| | - Biao Suo
- College of Food Science and Technology, Henan Agricultural University, Zhengzhou, China; Key Laboratory of Staple Grain Processing, Ministry of Agriculture and Rural Affairs, Zhengzhou, China; National R&D Center for Frozen Rice & Wheat Products Processing Technology, Henan Engineering Laboratory of Quick-Frozen Flour-Rice Food and Prepared Food, Henan Agricultural University, Zhengzhou, China.
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5
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Morawska LP, Kuipers OP. Transcriptome analysis and prediction of the metabolic state of stress-induced viable but non-culturable Bacillus subtilis cells. Sci Rep 2022; 12:18015. [PMID: 36289289 PMCID: PMC9605947 DOI: 10.1038/s41598-022-21102-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 09/22/2022] [Indexed: 01/24/2023] Open
Abstract
Many bacteria adapt their physiology and enter the viable but non-culturable state to survive prolonged exposure to adverse environmental conditions. The VBNC cells maintain active metabolism, membrane integrity and gene transcription. However, they lose the ability to form colonies on a conventional culture media. Thus, standard colony counting methods cannot detect these alive but dormant cells. The Gram-positive bacterium Bacillus subtilis was found to enter the VBNC state when pre-exposed to osmotic stress and treated with a lethal dose of kanamycin. These cells reduced their metabolic activity, ceased growth and division and became kanamycin-tolerant. Interestingly, despite active metabolism, the majority of the kanamycin tolerant cells could not be revived on LB agar. In this study, we use a robust RNA-Seq technique to elucidate the differences in transcriptional profiles of B. subtilis VBNC cells. A comparative analysis of differently expressed genes and operons performed in this study indicates high similarities in transcriptional responses of VBNC and kanamycin-sensitive cells to antibiotic treatment. Moreover, this work reveals that VBNC cells strongly upregulate genes involved in proline uptake and catabolism, suggesting a putative role of proline as nutrient in VBNC cells.
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Affiliation(s)
- Luiza P Morawska
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Oscar P Kuipers
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands.
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RefZ and Noc Act Synthetically to Prevent Aberrant Divisions during Bacillus subtilis Sporulation. J Bacteriol 2022; 204:e0002322. [PMID: 35506695 DOI: 10.1128/jb.00023-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During sporulation, Bacillus subtilis undergoes an atypical cell division that requires overriding mechanisms that protect chromosomes from damage and ensure inheritance by daughter cells. Instead of assembling between segregated chromosomes at midcell, the FtsZ-ring coalesces polarly, directing division over one chromosome. The DNA-binding protein RefZ facilitates the timely assembly of polar Z-rings and partially defines the region of chromosome initially captured in the forespore. RefZ binds to motifs (RBMs) located proximal to the origin of replication (oriC). Although refZ and the RBMs are conserved across the Bacillus genus, a refZ deletion mutant sporulates with wild-type efficiency, so the functional significance of RefZ during sporulation remains unclear. To further investigate RefZ function, we performed a candidate-based screen for synthetic sporulation defects by combining ΔrefZ with deletions of genes previously implicated in FtsZ regulation and/or chromosome capture. Combining ΔrefZ with deletions of ezrA, sepF, parA, or minD did not detectably affect sporulation. In contrast, a ΔrefZ Δnoc mutant exhibited a sporulation defect, revealing a genetic interaction between RefZ and Noc. Using reporters of sporulation progression, we determined the ΔrefZ Δnoc mutant exhibited sporulation delays after Spo0A activation but prior to late sporulation, with a subset of cells failing to divide polarly or activate the first forespore-specific sigma factor, SigF. The ΔrefZ Δnoc mutant also exhibited extensive dysregulation of cell division, producing cells with extra, misplaced, or otherwise aberrant septa. Our results reveal a previously unknown epistatic relationship that suggests refZ and noc contribute synthetically to regulating cell division and supporting spore development. IMPORTANCE The DNA-binding protein RefZ and its binding sites (RBMs) are conserved in sequence and location on the chromosome across the Bacillus genus and contribute to the timing of polar FtsZ-ring assembly during sporulation. Only a small number of noncoding and nonregulatory DNA motifs are known to be conserved in chromosomal position in bacteria, suggesting there is strong selective pressure for their maintenance; however, a refZ deletion mutant sporulates efficiently, providing no clues as to their functional significance. Here, we find that in the absence of the nucleoid occlusion factor Noc, deletion of refZ results in a sporulation defect characterized by developmental delays and aberrant divisions.
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7
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Awuni E. Status of Targeting MreB for the Development of Antibiotics. Front Chem 2020; 7:884. [PMID: 31998684 PMCID: PMC6965359 DOI: 10.3389/fchem.2019.00884] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 12/06/2019] [Indexed: 12/15/2022] Open
Abstract
Although many prospective antibiotic targets are known, bacterial infections and resistance to antibiotics remain a threat to public health partly because the druggable potentials of most of these targets have yet to be fully tapped for the development of a new generation of therapeutics. The prokaryotic actin homolog MreB is one of the important antibiotic targets that are yet to be significantly exploited. MreB is a bacterial cytoskeleton protein that has been widely studied and is associated with the determination of rod shape as well as important subcellular processes including cell division, chromosome segregation, cell wall morphogenesis, and cell polarity. Notwithstanding that MreB is vital and conserved in most rod-shaped bacteria, no approved antibiotics targeting it are presently available. Here, the status of targeting MreB for the development of antibiotics is concisely summarized. Expressly, the known therapeutic targets and inhibitors of MreB are presented, and the way forward in the search for a new generation of potent inhibitors of MreB briefly discussed.
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Affiliation(s)
- Elvis Awuni
- Department of Biochemistry, School of Biological Sciences, CANS, University of Cape Coast, Cape Coast, Ghana
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8
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Jorgenson MA, Young KD. YtfB, an OapA Domain-Containing Protein, Is a New Cell Division Protein in Escherichia coli. J Bacteriol 2018; 200:e00046-18. [PMID: 29686141 PMCID: PMC5996693 DOI: 10.1128/jb.00046-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 04/18/2018] [Indexed: 12/15/2022] Open
Abstract
While screening the Pfam database for novel peptidoglycan (PG) binding modules, we identified the OapA domain, which is annotated as a LysM-like domain. LysM domains bind PG and mediate localization to the septal ring. In the Gram-negative bacterium Escherichia coli, an OapA domain is present in YtfB, an inner membrane protein of unknown function but whose overproduction causes cells to filament. Together, these observations suggested that YtfB directly affects cell division, most likely through its OapA domain. Here, we show that YtfB accumulates at the septal ring and that its action requires the division-initiating protein FtsZ and, to a lesser extent, ZipA, an early recruit to the septalsome. While the loss of YtfB had no discernible impact, a mutant lacking both YtfB and DedD (a known cell division protein) grew as filamentous cells. The YtfB OapA domain by itself also localized to sites of division, and this localization was enhanced by the presence of denuded PGs. Finally, the OapA domain bound PG, though binding did not depend on the formation of denuded glycans. Collectively, our findings demonstrate that YtfB is a cell division protein whose function is related to cell wall hydrolases.IMPORTANCE All living cells must divide in order to thrive. In bacteria, this involves the coordinated activities of a large number of proteins that work in concert to constrict the cell. Knowing which proteins contribute to this process and how they function is fundamental. Here, we identify a new member of the cell division apparatus in the Gram-negative bacterium Escherichia coli whose function is related to the generation of a transient cell wall structure. These findings deepen our understanding of bacterial cell division.
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Affiliation(s)
- Matthew A Jorgenson
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Kevin D Young
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
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CbtA toxin of Escherichia coli inhibits cell division and cell elongation via direct and independent interactions with FtsZ and MreB. PLoS Genet 2017; 13:e1007007. [PMID: 28931012 PMCID: PMC5624674 DOI: 10.1371/journal.pgen.1007007] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 10/02/2017] [Accepted: 09/06/2017] [Indexed: 12/12/2022] Open
Abstract
The toxin components of toxin-antitoxin modules, found in bacterial plasmids, phages, and chromosomes, typically target a single macromolecule to interfere with an essential cellular process. An apparent exception is the chromosomally encoded toxin component of the E. coli CbtA/CbeA toxin-antitoxin module, which can inhibit both cell division and cell elongation. A small protein of only 124 amino acids, CbtA, was previously proposed to interact with both FtsZ, a tubulin homolog that is essential for cell division, and MreB, an actin homolog that is essential for cell elongation. However, whether or not the toxic effects of CbtA are due to direct interactions with these predicted targets is not known. Here, we genetically separate the effects of CbtA on cell elongation and cell division, showing that CbtA interacts directly and independently with FtsZ and MreB. Using complementary genetic approaches, we identify the functionally relevant target surfaces on FtsZ and MreB, revealing that in both cases, CbtA binds to surfaces involved in essential cytoskeletal filament architecture. We show further that each interaction contributes independently to CbtA-mediated toxicity and that disruption of both interactions is required to alleviate the observed toxicity. Although several other protein modulators are known to target FtsZ, the CbtA-interacting surface we identify represents a novel inhibitory target. Our findings establish CbtA as a dual function toxin that inhibits both cell division and cell elongation via direct and independent interactions with FtsZ and MreB. Bacterially encoded toxin-antitoxin systems, which consist of a small toxin protein that is co-produced with a neutralizing antitoxin, are a potential avenue for the identification of novel antibiotic targets. These toxins typically target essential cellular processes, causing growth arrest or cell death when unchecked by the antitoxin. Our study is focused on the CbtA toxin of E. coli, which was known to inhibit both bacterial cell division and also bacterial cell elongation (the process by which rod-shaped bacteria grow prior to cell division). We report that the effects of CbtA on cell division and cell elongation are genetically separable, and that they are due to direct and independent interactions with its targets FtsZ and MreB, essential cytoskeletal proteins that direct cell division and cell elongation, respectively. Our genetic analysis defines the functionally relevant target surfaces on FtsZ and MreB; in the case of FtsZ this surface represents a novel inhibitory target. As a dual-function toxin that independently targets two essential cytoskeletal elements, CbtA could guide the design of dual-function antibiotics whose ability to independently target more than one essential cellular process might impede the development of drug resistance, which is a growing public health threat.
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Polyvalent Proteins, a Pervasive Theme in the Intergenomic Biological Conflicts of Bacteriophages and Conjugative Elements. J Bacteriol 2017; 199:JB.00245-17. [PMID: 28559295 PMCID: PMC5512222 DOI: 10.1128/jb.00245-17] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 05/17/2017] [Indexed: 12/29/2022] Open
Abstract
Intense biological conflicts between prokaryotic genomes and their genomic parasites have resulted in an arms race in terms of the molecular “weaponry” deployed on both sides. Using a recursive computational approach, we uncovered a remarkable class of multidomain proteins with 2 to 15 domains in the same polypeptide deployed by viruses and plasmids in such conflicts. Domain architectures and genomic contexts indicate that they are part of a widespread conflict strategy involving proteins injected into the host cell along with parasite DNA during the earliest phase of infection. Their unique feature is the combination of domains with highly disparate biochemical activities in the same polypeptide; accordingly, we term them polyvalent proteins. Of the 131 domains in polyvalent proteins, a large fraction are enzymatic domains predicted to modify proteins, target nucleic acids, alter nucleotide signaling/metabolism, and attack peptidoglycan or cytoskeletal components. They further contain nucleic acid-binding domains, virion structural domains, and 40 novel uncharacterized domains. Analysis of their architectural network reveals both pervasive common themes and specialized strategies for conjugative elements and plasmids or (pro)phages. The themes include likely processing of multidomain polypeptides by zincin-like metallopeptidases and mechanisms to counter restriction or CRISPR/Cas systems and jump-start transcription or replication. DNA-binding domains acquired by eukaryotes from such systems have been reused in XPC/RAD4-dependent DNA repair and mitochondrial genome replication in kinetoplastids. Characterization of the novel domains discovered here, such as RNases and peptidases, are likely to aid in the development of new reagents and elucidation of the spread of antibiotic resistance. IMPORTANCE This is the first report of the widespread presence of large proteins, termed polyvalent proteins, predicted to be transmitted by genomic parasites such as conjugative elements, plasmids, and phages during the initial phase of infection along with their DNA. They are typified by the presence of multiple domains with disparate activities combined in the same protein. While some of these domains are predicted to assist the invasive element in replication, transcription, or protection of their DNA, several are likely to target various host defense systems or modify the host to favor the parasite's life cycle. Notably, DNA-binding domains from these systems have been transferred to eukaryotes, where they have been incorporated into DNA repair and mitochondrial genome replication systems.
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