1
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Chengalroyen MD, Mehaffy C, Lucas M, Bauer N, Raphela ML, Oketade N, Warner DF, Lewinsohn DA, Lewinsohn DM, Dobos KM, Mizrahi V. Modulation of riboflavin biosynthesis and utilization in mycobacteria. Microbiol Spectr 2024:e0320723. [PMID: 38916330 DOI: 10.1128/spectrum.03207-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 05/17/2024] [Indexed: 06/26/2024] Open
Abstract
Riboflavin (vitamin B2) is the precursor of the flavin coenzymes, FAD and FMN, which play a central role in cellular redox metabolism. While humans must obtain riboflavin from dietary sources, certain microbes, including Mycobacterium tuberculosis (Mtb), can biosynthesize riboflavin de novo. Riboflavin precursors have also been implicated in the activation of mucosal-associated invariant T (MAIT) cells which recognize metabolites derived from the riboflavin biosynthesis pathway complexed to the MHC-I-like molecule, MR1. To investigate the biosynthesis and function of riboflavin and its pathway intermediates in mycobacterial metabolism and physiology, we constructed conditional knockdowns (hypomorphs) in riboflavin biosynthesis and utilization genes in Mycobacterium smegmatis (Msm) and Mtb by inducible CRISPR interference. Using this comprehensive panel of hypomorphs, we analyzed the impact of gene silencing on viability, on the transcription of (other) riboflavin pathway genes, on the levels of the pathway proteins, and on riboflavin itself. Our results revealed that (i) despite lacking a canonical transporter, both Msm and Mtb assimilate exogenous riboflavin when supplied at high concentration; (ii) there is functional redundancy in lumazine synthase activity in Msm; (iii) silencing of ribA2 or ribF is profoundly bactericidal in Mtb; and (iv) in Msm, ribA2 silencing results in concomitant knockdown of other pathway genes coupled with RibA2 and riboflavin depletion and is also bactericidal. In addition to their use in genetic validation of potential drug targets for tuberculosis, this collection of hypomorphs provides a useful resource for future studies investigating the role of pathway intermediates in MAIT cell recognition of mycobacteria. IMPORTANCE The pathway for biosynthesis and utilization of riboflavin, precursor of the essential coenzymes, FMN and FAD, is of particular interest in the flavin-rich pathogen, Mycobacterium tuberculosis (Mtb), for two important reasons: (i) the pathway includes potential tuberculosis (TB) drug targets and (ii) intermediates from the riboflavin biosynthesis pathway provide ligands for mucosal-associated invariant T (MAIT) cells, which have been implicated in TB pathogenesis. However, the riboflavin pathway is poorly understood in mycobacteria, which lack canonical mechanisms to transport this vitamin and to regulate flavin coenzyme homeostasis. By conditionally disrupting each step of the pathway and assessing the impact on mycobacterial viability and on the levels of the pathway proteins as well as riboflavin, our work provides genetic validation of the riboflavin pathway as a target for TB drug discovery and offers a resource for further exploring the association between riboflavin biosynthesis, MAIT cell activation, and TB infection and disease.
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Affiliation(s)
- Melissa D Chengalroyen
- Molecular Mycobacteriology Research Unit, Institute of Infectious Disease and Molecular Medicine & Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Carolina Mehaffy
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Megan Lucas
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Niel Bauer
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Mabule L Raphela
- Molecular Mycobacteriology Research Unit, Institute of Infectious Disease and Molecular Medicine & Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Nurudeen Oketade
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Digby F Warner
- Molecular Mycobacteriology Research Unit, Institute of Infectious Disease and Molecular Medicine & Department of Pathology, University of Cape Town, Cape Town, South Africa
- Wellcome Centre for Infectious Disease Research in Africa, University of Cape Town, Cape Town, South Africa
| | | | - David M Lewinsohn
- Oregon Health and Science University, Portland, Oregon, USA
- Portland VA Medical Center, Portland, Oregon, USA
| | - Karen M Dobos
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Valerie Mizrahi
- Molecular Mycobacteriology Research Unit, Institute of Infectious Disease and Molecular Medicine & Department of Pathology, University of Cape Town, Cape Town, South Africa
- Wellcome Centre for Infectious Disease Research in Africa, University of Cape Town, Cape Town, South Africa
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2
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Stefan A, Mucchi A, Hochkoeppler A. The catalytic action of human d-lactate dehydrogenase is severely inhibited by oxalate and is impaired by mutations triggering d-lactate acidosis. Arch Biochem Biophys 2024; 754:109932. [PMID: 38373542 DOI: 10.1016/j.abb.2024.109932] [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: 11/03/2023] [Revised: 01/29/2024] [Accepted: 02/16/2024] [Indexed: 02/21/2024]
Abstract
d-lactate dehydrogenases are known to be expressed by prokaryotes and by eukaryotic invertebrates, and over the years the functional and structural features of some bacterial representatives of this enzyme ensemble have been investigated quite in detail. Remarkably, a human gene coding for a putative d-lactate dehydrogenase (DLDH) was identified and characterized, disclosing the occurrence of alternative splicing of its primary transcript. This translates into the expression of two human DLDH (hDLDH) isoforms, the molecular mass of which is expected to differ by 2.7 kDa. However, no information on these two hDLDH isoforms is available at the protein level. Here we report on the catalytic action of these enzymes, along with a first analysis of their structural features. In particular, we show that hDLDH is strictly stereospecific, with the larger isoform (hDLDH-1) featuring higher activity at the expense of d-lactate when compared to its smaller counterpart (hDLDH-2). Furthermore, we found that hDLDH is strongly inhibited by oxalate, as indicated by a Ki equal to 1.2 μM for this dicarboxylic acid. Structurally speaking, hDLDH-1 and hDLDH-2 were determined, by means of gel filtration and dynamic light scattering experiments, to be a hexamer and a tetramer, respectively. Moreover, in agreement with previous studies performed with human mitochondria, we identified FAD as the cofactor of hDLDH, and we report here a model of FAD binding by the human d-lactate dehydrogenase. Interestingly, the mutations W323C and T412 M negatively affect the activity of hDLDH, most likely by impairing the enzyme electron-acceptor site.
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Affiliation(s)
- Alessandra Stefan
- Department of Pharmacy and Biotechnology, University of Bologna, Viale Risorgimento 4, 40136, Bologna, Italy; CSGI, University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, FI, Italy
| | - Alberto Mucchi
- Department of Industrial Chemistry "Toso Montanari", Viale Risorgimento 4, 40136, Bologna, Italy
| | - Alejandro Hochkoeppler
- Department of Pharmacy and Biotechnology, University of Bologna, Viale Risorgimento 4, 40136, Bologna, Italy; CSGI, University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, FI, Italy.
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3
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Panter S, Ayekoi A, Tesche J, Chen J, Illarionov B, Bacher A, Fischer M, Weber S. Shining a Spotlight on Methyl Groups: Photochemically Induced Dynamic Nuclear Polarization Spectroscopy of 5-Deazariboflavin and Its Nor Analogs. Int J Mol Sci 2024; 25:848. [PMID: 38255921 PMCID: PMC10815406 DOI: 10.3390/ijms25020848] [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: 12/08/2023] [Revised: 01/07/2024] [Accepted: 01/08/2024] [Indexed: 01/24/2024] Open
Abstract
5-Deazaflavins are analogs of naturally occurring flavin cofactors. They serve as substitutes for natural flavin cofactors to investigate and modify the reaction pathways of flavoproteins. Demethylated 5-deazaflavins are potential candidates for artificial cofactors, allowing us to fine-tune the reaction kinetics and absorption characteristics of flavoproteins. In this contribution, demethylated 5-deazariboflavin radicals are investigated (1) to assess the influence of the methyl groups on the electronic structure of the 5-deazaflavin radical and (2) to explore their photophysical properties with regard to their potential as artificial cofactors. We determined the proton hyperfine structure of demethylated 5-deazariboflavins using photochemically induced dynamic nuclear polarization (photo-CIDNP) spectroscopy, as well as density functional theory (DFT). To provide context, we compare our findings to a study of flavin mononucleotide (FMN) derivatives. We found a significant influence of the methylation pattern on the absorption properties, as well as on the proton hyperfine coupling ratios of the xylene moiety, which appears to be solvent-dependent. This effect is enhanced by the replacement of N5 by C5-H in 5-deazaflavin derivatives compared to their respective flavin counterparts.
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Affiliation(s)
- Sabrina Panter
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg, Germany; (S.P.); (A.A.)
| | - Audrey Ayekoi
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg, Germany; (S.P.); (A.A.)
| | - Jannis Tesche
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg, Germany; (S.P.); (A.A.)
| | - Jing Chen
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg, Germany; (S.P.); (A.A.)
| | - Boris Illarionov
- Institut für Lebensmittelchemie, Universität Hamburg, Grindelallee 117, 20146 Hamburg, Germany; (B.I.); (M.F.)
| | - Adelbert Bacher
- TUM School of Natural Sciences, Technische Universität München, Lichtenbergstr. 4, 85747 Garching, Germany;
| | - Markus Fischer
- Institut für Lebensmittelchemie, Universität Hamburg, Grindelallee 117, 20146 Hamburg, Germany; (B.I.); (M.F.)
| | - Stefan Weber
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg, Germany; (S.P.); (A.A.)
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4
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Bassani I, Bellini R, Vizzarro A, Coti C, Pozzovivo V, Barbieri D, Pirri CF, Verga F, Menin B. Biogeochemical characterization of four depleted gas reservoirs for conversion into underground hydrogen storage. Environ Microbiol 2023; 25:3683-3702. [PMID: 37964633 DOI: 10.1111/1462-2920.16538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 10/31/2023] [Indexed: 11/16/2023]
Abstract
Depleted gas reservoirs are a valuable option for underground hydrogen storage (UHS). However, different classes of microorganisms, which are capable of using free H2 as a reducing agent for their metabolism, inhabit deep underground formations and can potentially affect the storage. This study integrates metagenomics based on Illumina-NGS sequencing of bacterial and archaeal 16S rRNA and dsrB and mcrA functional genes to unveil the composition and the variability of indigenous microbial populations of four Italian depleted reservoirs. The obtained mcrA sequences allow us to implement the existing taxonomic database for mcrA gene sequences with newly classified sequences obtained from the Italian gas reservoirs. Moreover, the KEGG and COG predictive functional annotation was used to highlight the metabolic pathways potentially associated with hydrogenotrophic metabolisms. The analyses revealed the specificity of each reservoir microbial community, and taxonomic and functional data highlighted the presence of an enriched number of taxa, whose activity depends on both reservoir hydrochemical composition and nutrient availability, of potential relevance in the context of UHS. This study is the very first to address the profiling of the microbial population and allowed us to perform a preliminary assessment of UHS feasibility in Italy.
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Affiliation(s)
- Ilaria Bassani
- Centre for Sustainable Future Technologies, Fondazione Istituto Italiano di Tecnologia, Turin, Italy
| | - Ruggero Bellini
- Centre for Sustainable Future Technologies, Fondazione Istituto Italiano di Tecnologia, Turin, Italy
| | - Arianna Vizzarro
- Centre for Sustainable Future Technologies, Fondazione Istituto Italiano di Tecnologia, Turin, Italy
| | | | | | | | - Candido Fabrizio Pirri
- Centre for Sustainable Future Technologies, Fondazione Istituto Italiano di Tecnologia, Turin, Italy
- Department of Applied Science and Technology, Politecnico di Torino, Turin, Italy
| | - Francesca Verga
- Department of Applied Science and Technology, Politecnico di Torino, Turin, Italy
| | - Barbara Menin
- Centre for Sustainable Future Technologies, Fondazione Istituto Italiano di Tecnologia, Turin, Italy
- National Research Council, Institute of Agricultural Biology and Biotechnology (CNR-IBBA), Milan, Italy
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5
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Kountz DJ, Balskus EP. A diversified, widespread microbial gene cluster encodes homologs of methyltransferases involved in methanogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.31.551370. [PMID: 37577662 PMCID: PMC10418091 DOI: 10.1101/2023.07.31.551370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Analyses of microbial genomes have revealed unexpectedly wide distributions of enzymes from specialized metabolism, including methanogenesis, providing exciting opportunities for discovery. Here, we identify a family of gene clusters (the type 1 mlp gene clusters (MGCs)) that encodes homologs of the soluble coenzyme M methyltransferases (SCMTs) involved in methylotrophic methanogenesis and is widespread in bacteria and archaea. Type 1 MGCs are expressed and regulated in medically, environmentally, and industrially important organisms, making them likely to be physiologically relevant. Enzyme annotation, analysis of genomic context, and biochemical experiments suggests these gene clusters play a role in methyl-sulfur and/or methyl-selenide metabolism in numerous anoxic environments, including the human gut microbiome, potentially impacting sulfur and selenium cycling in diverse, anoxic environments.
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Affiliation(s)
- Duncan J. Kountz
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Emily P. Balskus
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
- Howard Hughes Medical Institute, Harvard University, Cambridge, Massachusetts 02138, United States
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6
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Yang G, Wijma HJ, Rozeboom HJ, Mascotti ML, Fraaije MW. Identification and characterization of archaeal and bacterial F 420 -dependent thioredoxin reductases. FEBS J 2023; 290:4777-4791. [PMID: 37403630 DOI: 10.1111/febs.16896] [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: 03/04/2023] [Revised: 06/19/2023] [Accepted: 07/04/2023] [Indexed: 07/06/2023]
Abstract
The thioredoxin pathway is an antioxidant system present in most organisms. Electrons flow from a thioredoxin reductase to thioredoxin at the expense of a specific electron donor. Most known thioredoxin reductases rely on NADPH as a reducing cofactor. Yet, in 2016, a new type of thioredoxin reductase was discovered in Archaea which utilize instead a reduced deazaflavin cofactor (F420 H2 ). For this reason, the respective enzyme was named deazaflavin-dependent flavin-containing thioredoxin reductase (DFTR). To have a broader understanding of the biochemistry of DFTRs, we identified and characterized two other archaeal representatives. A detailed kinetic study, which included pre-steady state kinetic analyses, revealed that these two DFTRs are highly specific for F420 H2 while displaying marginal activity with NADPH. Nevertheless, they share mechanistic features with the canonical thioredoxin reductases that are dependent on NADPH (NTRs). A detailed structural analysis led to the identification of two key residues that tune cofactor specificity of DFTRs. This allowed us to propose a DFTR-specific sequence motif that enabled for the first time the identification and experimental characterization of a bacterial DFTR.
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Affiliation(s)
- Guang Yang
- Molecular Enzymology Group, University of Groningen, The Netherlands
| | - Hein J Wijma
- Molecular Enzymology Group, University of Groningen, The Netherlands
| | | | - Maria Laura Mascotti
- Molecular Enzymology Group, University of Groningen, The Netherlands
- IMIBIO-SL CONICET, Facultad de Química Bioquímica y Farmacia, Universidad Nacional de San Luis, Argentina
| | - Marco W Fraaije
- Molecular Enzymology Group, University of Groningen, The Netherlands
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7
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Chengalroyen MD, Mehaffy C, Lucas M, Bauer N, Raphela ML, Oketade N, Warner DF, Lewinsohn DA, Lewinsohn DM, Dobos KM, Mizrahi V. Modulation of riboflavin biosynthesis and utilization in mycobacteria. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.30.555301. [PMID: 37693561 PMCID: PMC10491194 DOI: 10.1101/2023.08.30.555301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Riboflavin (vitamin B2) is the precursor of the flavin coenzymes, FAD and FMN, which play a central role in cellular redox metabolism. While humans must obtain riboflavin from dietary sources, certain microbes, including Mycobacterium tuberculosis (Mtb), can biosynthesize riboflavin de novo. Riboflavin precursors have also been implicated in the activation of mucosal-associated invariant T (MAIT) cells which recognize metabolites derived from the riboflavin biosynthesis pathway complexed to the MHC-I-like molecule, MR1. To investigate the biosynthesis and function of riboflavin and its pathway intermediates in mycobacterial metabolism, physiology and MAIT cell recognition, we constructed conditional knockdowns (hypomorphs) in riboflavin biosynthesis and utilization genes in Mycobacterium smegmatis (Msm) and Mtb by inducible CRISPR interference. Using this comprehensive panel of hypomorphs, we analyzed the impact of gene silencing on viability, on the transcription of (other) riboflavin pathway genes, on the levels of the pathway proteins and on riboflavin itself. Our results revealed that (i) despite lacking a canonical transporter, both Msm and Mtb assimilate exogenous riboflavin when supplied at high concentration; (ii) there is functional redundancy in lumazine synthase activity in Msm; (iii) silencing of ribA2 or ribF is profoundly bactericidal in Mtb; and (iv) in Msm, ribA2 silencing results in concomitant knockdown of other pathway genes coupled with RibA2 and riboflavin depletion and is also bactericidal. In addition to their use in genetic validation of potential drug targets for tuberculosis, this collection of hypomorphs provides a useful resource for investigating the role of pathway intermediates in MAIT cell recognition of mycobacteria.
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Affiliation(s)
- Melissa D. Chengalroyen
- Molecular Mycobacteriology Research Unit, Institute of Infectious Disease and Molecular Medicine & Department of Pathology, University of Cape Town, South Africa
| | - Carolina Mehaffy
- Department of Microbiology, Immunology and Pathology, Colorado State University, Colorado, USA
| | - Megan Lucas
- Department of Microbiology, Immunology and Pathology, Colorado State University, Colorado, USA
| | - Niel Bauer
- Department of Microbiology, Immunology and Pathology, Colorado State University, Colorado, USA
| | - Mabule L. Raphela
- Molecular Mycobacteriology Research Unit, Institute of Infectious Disease and Molecular Medicine & Department of Pathology, University of Cape Town, South Africa
| | - Nurudeen Oketade
- Department of Microbiology, Immunology and Pathology, Colorado State University, Colorado, USA
| | - Digby F. Warner
- Molecular Mycobacteriology Research Unit, Institute of Infectious Disease and Molecular Medicine & Department of Pathology, University of Cape Town, South Africa
- Wellcome Centre for Infectious Disease Research in Africa, University of Cape Town, South Africa
| | | | - David M. Lewinsohn
- Oregon Health and Science University, Oregon, USA
- Portland VA Medical Center, Oregon, USA
| | - Karen M. Dobos
- Department of Microbiology, Immunology and Pathology, Colorado State University, Colorado, USA
| | - Valerie Mizrahi
- Molecular Mycobacteriology Research Unit, Institute of Infectious Disease and Molecular Medicine & Department of Pathology, University of Cape Town, South Africa
- Wellcome Centre for Infectious Disease Research in Africa, University of Cape Town, South Africa
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8
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Brown HJ, Duggin IG. Diversity and Potential Multifunctionality of Archaeal CetZ Tubulin-like Cytoskeletal Proteins. Biomolecules 2023; 13:biom13010134. [PMID: 36671519 PMCID: PMC9856176 DOI: 10.3390/biom13010134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 01/04/2023] [Accepted: 01/04/2023] [Indexed: 01/11/2023] Open
Abstract
Tubulin superfamily (TSF) proteins are widespread, and are known for their multifaceted roles as cytoskeletal proteins underpinning many basic cellular functions, including morphogenesis, division, and motility. In eukaryotes, tubulin assembles into microtubules, a major component of the dynamic cytoskeletal network of fibres, whereas the bacterial homolog FtsZ assembles the division ring at midcell. The functions of the lesser-known archaeal TSF proteins are beginning to be identified and show surprising diversity, including homologs of tubulin and FtsZ as well as a third archaea-specific family, CetZ, implicated in the regulation of cell shape and possibly other unknown functions. In this study, we define sequence and structural characteristics of the CetZ family and CetZ1 and CetZ2 subfamilies, identify CetZ groups and diversity amongst archaea, and identify potential functional relationships through analysis of the genomic neighbourhoods of cetZ genes. We identified at least three subfamilies of orthologous CetZ proteins in the archaeal class Halobacteria, including CetZ1 and CetZ2 as well as a novel uncharacterized subfamily. CetZ1 and CetZ2 were correlated to one another as well as to cell shape and motility phenotypes across diverse Halobacteria. Among other known CetZ clusters in orders Archaeoglobales, Methanomicrobiales, Methanosarcinales, and Thermococcales, an additional uncharacterized group from Archaeoglobales and Methanomicrobiales is affiliated strongly with Halobacteria CetZs, suggesting that they originated via horizontal transfer. Subgroups of Halobacteria CetZ2 and Thermococcales CetZ genes were found adjacent to different type IV pili regulons, suggesting potential utilization of CetZs by type IV systems. More broadly conserved cetZ gene neighbourhoods include nucleotide and cofactor biosynthesis (e.g., F420) and predicted cell surface sugar epimerase genes. These findings imply that CetZ subfamilies are involved in multiple functions linked to the cell surface, biosynthesis, and motility.
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9
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Hu CJ, Xian WD, Lv YQ, Peng CX, Shan RX, Cheng ZC, Lv Q, Tian Y, Jiao JY, Tan S, Li WJ. Caldovatus aquaticus sp. nov., a moderately thermophilic bacterium isolated from hot spring microbial mat. Int J Syst Evol Microbiol 2022; 72. [PMID: 36748592 DOI: 10.1099/ijsem.0.005627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Two closely related, aerobic, Gram-stain-negative, motile, oval-shaped, non-endospore-forming, moderately thermophilic bacteria, designated strains SYSU G05006T and SYSU G05005, were isolated from a bioreactor enrichment and the original sample was collected from Rehai National Park, Tengchong, Yunnan Province, PR China. The results of phylogenetic analysis based on the 16S rRNA gene sequences indicated that these two strains were closely related to Caldovatus sediminis YIM 72346T (96.75 and 96.89 % sequence similarity, respectively). The whole genome size of strain SYSU G05006T was 3.87 Mbp with a DNA G+C content of 75.33 mol%. The average nucleotide identity (ANI based on the MUMmer algorithm≤90.31 % and ANI based on blast≤89.36 %) and digital DNA-DNA hybridization (≤35.10 %) values between strain SYSU G05006T and other members of the family Acetobacteraceae were all lower than the threshold values recommended for distinguishing novel prokaryotic species. Optimal growth of the strain was observed at 55 °C and pH 6.0. Ubiquinone-10 was the predominant respiratory lipoquinone. The major cellular fatty acids included iso-C14 : 0, C16 : 1 ω5c, summed feature 5 and summed feature 7. The major polar lipids consisted of diphosphatidylglycerol, one unidentified aminolipid, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, two unidentified phospholipids and two unidentified lipids. Based on results of phylogenetic analyses, comparative genomics and phenotypic characteristics, we describe a new species of the genus Caldovatus represented by strain SYSU G05006T (=KCTC 82831T=MCCC 1K06125T), for which we propose the name Caldovatus aquaticus sp. nov.
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Affiliation(s)
- Chao-Jian Hu
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, PR China.,School of Ecology, Sun Yat-Sen University, Guangzhou 510275, PR China
| | - Wen-Dong Xian
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, PR China.,School of Ecology, Sun Yat-Sen University, Guangzhou 510275, PR China.,Marine Science and Technology College, Zhejiang Ocean University, Zhoushan 316000, PR China
| | - Yi-Qing Lv
- School of Ecology, Sun Yat-Sen University, Guangzhou 510275, PR China
| | - Cheng-Xiang Peng
- School of Ecology, Sun Yat-Sen University, Guangzhou 510275, PR China
| | - Rong-Xu Shan
- School of Ecology, Sun Yat-Sen University, Guangzhou 510275, PR China
| | - Ze-Chang Cheng
- School of Ecology, Sun Yat-Sen University, Guangzhou 510275, PR China
| | - Qian Lv
- School of Ecology, Sun Yat-Sen University, Guangzhou 510275, PR China
| | - Ye Tian
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, PR China
| | - Jian-Yu Jiao
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, PR China
| | - Sha Tan
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, PR China
| | - Wen-Jun Li
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, PR China.,State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, PR China
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10
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Fu Y, Wang Z, Zhang Y, Shen G, Zhu X. Quantitative Evaluation of the Hydrogen‐Donating Abilities ofAmines and Amides in Acetonitrile. ChemistrySelect 2022. [DOI: 10.1002/slct.202202625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Yan‐Hua Fu
- College of Chemistry and Environmental Engineering Anyang Institute of Technology Anyang Henan 455000 China
| | - Zhen Wang
- College of Chemistry and Environmental Engineering Anyang Institute of Technology Anyang Henan 455000 China
| | - Yanwei Zhang
- College of Chemistry and Environmental Engineering Anyang Institute of Technology Anyang Henan 455000 China
| | - Guang‐Bin Shen
- School of Medical Engineering Jining Medical University Jining Shandong 272000 P. R. China
| | - Xiao‐Qing Zhu
- Department of Chemistry Nankai University Tianjin 300071 China
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11
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Microorganisms as New Sources of Energy. ENERGIES 2022. [DOI: 10.3390/en15176365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The use of fossil energy sources has a negative impact on the economic and socio-political stability of specific regions and countries, causing environmental changes due to the emission of greenhouse gases. Moreover, the stocks of mineral energy are limited, causing the demand for new types and forms of energy. Biomass is a renewable energy source and represents an alternative to fossil energy sources. Microorganisms produce energy from the substrate and biomass, i.e., from substances in the microenvironment, to maintain their metabolism and life. However, specialized microorganisms also produce specific metabolites under almost abiotic circumstances that often do not have the immediate task of sustaining their own lives. This paper presents the action of biogenic and biogenic–thermogenic microorganisms, which produce methane, alcohols, lipids, triglycerides, and hydrogen, thus often creating renewable energy from waste biomass. Furthermore, some microorganisms acquire new or improved properties through genetic interventions for producing significant amounts of energy. In this way, they clean the environment and can consume greenhouse gases. Particularly suitable are blue-green algae or cyanobacteria but also some otherwise pathogenic microorganisms (E. coli, Klebsiella, and others), as well as many other specialized microorganisms that show an incredible ability to adapt. Microorganisms can change the current paradigm, energy–environment, and open up countless opportunities for producing new energy sources, especially hydrogen, which is an ideal energy source for all systems (biological, physical, technological). Developing such energy production technologies can significantly change the already achieved critical level of greenhouse gases that significantly affect the climate.
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Schut GJ, Haja DK, Feng X, Poole FL, Li H, Adams MWW. An Abundant and Diverse New Family of Electron Bifurcating Enzymes With a Non-canonical Catalytic Mechanism. Front Microbiol 2022; 13:946711. [PMID: 35875533 PMCID: PMC9304861 DOI: 10.3389/fmicb.2022.946711] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 06/15/2022] [Indexed: 11/13/2022] Open
Abstract
Microorganisms utilize electron bifurcating enzymes in metabolic pathways to carry out thermodynamically unfavorable reactions. Bifurcating FeFe-hydrogenases (HydABC) reversibly oxidize NADH (E′∼−280 mV, under physiological conditions) and reduce protons to H2 gas (E°′−414 mV) by coupling this endergonic reaction to the exergonic reduction of protons by reduced ferredoxin (Fd) (E′∼−500 mV). We show here that HydABC homologs are surprisingly ubiquitous in the microbial world and are represented by 57 phylogenetically distinct clades but only about half are FeFe-hydrogenases. The others have replaced the hydrogenase domain with another oxidoreductase domain or they contain additional subunits, both of which enable various third reactions to be reversibly coupled to NAD+ and Fd reduction. We hypothesize that all of these enzymes carry out electron bifurcation and that their third substrates can include hydrogen peroxide, pyruvate, carbon monoxide, aldehydes, aryl-CoA thioesters, NADP+, cofactor F420, formate, and quinones, as well as many yet to be discovered. Some of the enzymes are proposed to be integral membrane-bound proton-translocating complexes. These different functionalities are associated with phylogenetically distinct clades and in many cases with specific microbial phyla. We propose that this new and abundant class of electron bifurcating enzyme be referred to as the Bfu family whose defining feature is a conserved bifurcating BfuBC core. This core contains FMN and six iron sulfur clusters and it interacts directly with ferredoxin (Fd) and NAD(H). Electrons to or from the third substrate are fed into the BfuBC core via BfuA. The other three known families of electron bifurcating enzyme (abbreviated as Nfn, EtfAB, and HdrA) contain a special FAD that bifurcates electrons to high and low potential pathways. The Bfu family are proposed to use a different electron bifurcation mechanism that involves a combination of FMN and three adjacent iron sulfur clusters, including a novel [2Fe-2S] cluster with pentacoordinate and partial non-Cys coordination. The absolute conservation of the redox cofactors of BfuBC in all members of the Bfu enzyme family indicate they have the same non-canonical mechanism to bifurcate electrons. A hypothetical catalytic mechanism is proposed as a basis for future spectroscopic analyses of Bfu family members.
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Affiliation(s)
- Gerrit J. Schut
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - Dominik K. Haja
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - Xiang Feng
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, United States
| | - Farris L. Poole
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, United States
| | - Michael W. W. Adams
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
- *Correspondence: Michael W. W. Adams, ; orcid.org/0000-0002-9796-5014
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Lee M, Drenth J, Trajkovic M, de Jong RM, Fraaije MW. Introducing an Artificial Deazaflavin Cofactor in Escherichia coli and Saccharomyces cerevisiae. ACS Synth Biol 2022; 11:938-952. [PMID: 35044755 PMCID: PMC8859854 DOI: 10.1021/acssynbio.1c00552] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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Deazaflavin-dependent
whole-cell conversions in well-studied and
industrially relevant microorganisms such as Escherichia coli and Saccharomyces cerevisiae have high potential
for the biocatalytic production of valuable compounds. The artificial
deazaflavin FOP (FO-5′-phosphate) can functionally substitute
the natural deazaflavin F420 and can be synthesized in
fewer steps, offering a solution to the limited availability of the
latter due to its complex (bio)synthesis. Herein we set out to produce
FOP in vivo as a scalable FOP production method and as a means for
FOP-mediated whole-cell conversions. Heterologous expression of the
riboflavin kinase from Schizosaccharomyces pombe enabled
in vivo phosphorylation of FO, which was supplied by either organic
synthesis ex vivo, or by a coexpressed FO synthase in vivo, producing
FOP in E. coli as well as in S. cerevisiae. Through combined approaches of enzyme engineering as well as optimization
of expression systems and growth media, we further improved the in
vivo FOP production in both organisms. The improved FOP production
yield in E. coli is comparable to the F420 yield of native F420-producing organisms such
as Mycobacterium smegmatis, but the former can be
achieved in a significantly shorter time frame. Our E. coli expression system has an estimated production rate of 0.078 μmol
L–1 h–1 and results in an intracellular
FOP concentration of about 40 μM, which is high enough to support
catalysis. In fact, we demonstrate the successful FOP-mediated whole-cell
conversion of ketoisophorone using E. coli cells.
In S. cerevisiae, in vivo FOP production by SpRFK using supplied FO was improved through media optimization
and enzyme engineering. Through structure-guided enzyme engineering,
a SpRFK variant with 7-fold increased catalytic efficiency
compared to the wild type was discovered. By using this variant in
optimized media conditions, FOP production yield in S. cerevisiae was 20-fold increased compared to the very low initial yield of
0.24 ± 0.04 nmol per g dry biomass. The results show that bacterial
and eukaryotic hosts can be engineered to produce the functional deazaflavin
cofactor mimic FOP.
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Affiliation(s)
- Misun Lee
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Jeroen Drenth
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Milos Trajkovic
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - René M. de Jong
- DSM Biotechnology Center, Alexander Fleminglaan 1, 2613 AX Delft, The Netherlands
| | - Marco W. Fraaije
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
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Fu YH, Wang Z, Wang K, Shen GB, Zhu XQ. Evaluation and comparison of antioxidant abilities of five bioactive molecules with C–H and O–H bonds in thermodynamics and kinetics. RSC Adv 2022; 12:27389-27395. [PMID: 36275999 PMCID: PMC9513755 DOI: 10.1039/d2ra04839f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 09/10/2022] [Indexed: 11/21/2022] Open
Abstract
In this work, the antioxidant abilities of NADH coenzyme analogue BNAH, F420 reduction prototype analogue F420H, vitamin C analogue iAscH−, caffeic acid, and (+)-catechin in acetonitrile in chemical reactions were studied and discussed.
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Affiliation(s)
- Yan-Hua Fu
- College of Chemistry and Environmental Engineering, Anyang Institute of Technology, Anyang, Henan, 455000, China
| | - Zhen Wang
- College of Chemistry and Environmental Engineering, Anyang Institute of Technology, Anyang, Henan, 455000, China
| | - Kai Wang
- College of Chemistry and Environmental Engineering, Anyang Institute of Technology, Anyang, Henan, 455000, China
| | - Guang-Bin Shen
- School of Medical Engineering, Jining Medical University, Jining, Shandong, 272000, P. R. China
| | - Xiao-Qing Zhu
- Department of Chemistry, Nankai University, Tianjin, 300071, China
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