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Islam Z, Kumar P. Inhibitors of riboflavin biosynthetic pathway enzymes as potential antibacterial drugs. Front Mol Biosci 2023; 10:1228763. [PMID: 37496776 PMCID: PMC10366380 DOI: 10.3389/fmolb.2023.1228763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 07/03/2023] [Indexed: 07/28/2023] Open
Abstract
Multiple drug resistance is the main obstacle in the treatment of bacterial diseases. Resistance against antibiotics demands the exploration of new antimicrobial drug targets. A variety of in silico and genetic approaches show that the enzymes of the riboflavin biosynthetic pathway are crucial for the survival of bacteria. This pathway is absent in humans thus enzymes of the riboflavin biosynthetic pathway are emerging drug targets for resistant pathogenic bacterial strains. Exploring the structural details, their mechanism of action, intermediate elucidation, and interaction analysis would help in designing suitable inhibitors of these enzymes. The riboflavin biosynthetic pathway consists of seven distinct enzymes, namely, 3,4-dihydroxy-2-butanone 4-phosphate synthase, GTP cyclohydrolase II, pyrimidine deaminase/reductase, phosphatase, lumazine synthase, and riboflavin synthase. The present review summarizes the research work that has been carried out on these enzymes in terms of their structures, active site architectures, and molecular mechanism of catalysis. This review also walks through small molecule inhibitors that have been developed against several of these enzymes.
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Affiliation(s)
- Zeyaul Islam
- Qatar Biomedical Research Institute (QBRI), Qatar Foundation, Hamad Bin Khalifa University, Doha, Qatar
| | - Pankaj Kumar
- Department of Biochemistry, Jamia Hamdard, New Delhi, India
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Yurgel SN, Johnson SA, Rice J, Sa N, Bailes C, Baumgartner J, Pitzer JE, Roop RM, Roje S. A novel formamidase is required for riboflavin biosynthesis in invasive bacteria. J Biol Chem 2022; 298:102377. [PMID: 35970388 PMCID: PMC9478397 DOI: 10.1016/j.jbc.2022.102377] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 08/10/2022] [Accepted: 08/11/2022] [Indexed: 11/03/2022] Open
Abstract
Biosynthesis of riboflavin, the precursor of the redox cofactors FMN and FAD, was thought to be well understood in bacteria, with all the pathway enzymes presumed to be known and essential. Our previous research has challenged this view by showing that, in the bacterium Sinorhizobium meliloti, deletion of the ribBA gene encoding the enzyme that catalyzes the initial steps on the riboflavin biosynthesis pathway only causes a reduction in flavin secretion rather than riboflavin auxotrophy. This finding led us to hypothesize that RibBA participates in the biosynthesis of flavins destined for secretion, while S. meliloti has another enzyme that performs this function for internal cellular metabolism. Here, we identify and biochemically characterize a novel formamidase (SMc02977) involved in the production of riboflavin for intracellular functions in S. meliloti. This catalyst, which we named Sm-BrbF, releases formate from the early riboflavin precursor 2-amino-5-formylamino-6-ribosylamino-4(3H)-pyrimidinone 5'-phosphate (AFRPP) to yield 2,5-diamino-6-ribosylamino-4(3H)-pyrimidinone 5'-phosphate (DARoPP). We show that homologs of this enzyme are present in many bacteria, are highly abundant in the Rhizobiales order, and that sequence homologs from Brucella abortus and Liberobacter solanacearum complement the riboflavin auxotrophy of the Sm1021ΔSMc02977 mutant. Furthermore, we show that the B. abortus enzyme (Bab2_0247, Ba-BrbF) is also an AFRPP formamidase, and that the bab2_0247 mutant is a riboflavin auxotroph exhibiting a lower level of intracellular infection than the wild-type strain. Finally, we show that Sm-BrbF and Ba-BrbF directly interact with other riboflavin biosynthesis pathway enzymes. Together, our results provide novel insight into the intricacies of riboflavin biosynthesis in bacteria.
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Affiliation(s)
- Svetlana N Yurgel
- Grain Legume Genetics and Physiology Research Unit, USDA, ARS, Prosser, WA, USA.
| | - Skylar A Johnson
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Jennifer Rice
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Na Sa
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Clayton Bailes
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - John Baumgartner
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - Josh E Pitzer
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - R Martin Roop
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - Sanja Roje
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
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Biological Properties of Vitamins of the B-Complex, Part 1: Vitamins B1, B2, B3, and B5. Nutrients 2022; 14:nu14030484. [PMID: 35276844 PMCID: PMC8839250 DOI: 10.3390/nu14030484] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 01/16/2022] [Accepted: 01/17/2022] [Indexed: 02/06/2023] Open
Abstract
This review summarizes the current knowledge on essential vitamins B1, B2, B3, and B5. These B-complex vitamins must be taken from diet, with the exception of vitamin B3, that can also be synthetized from amino acid tryptophan. All of these vitamins are water soluble, which determines their main properties, namely: they are partly lost when food is washed or boiled since they migrate to the water; the requirement of membrane transporters for their permeation into the cells; and their safety since any excess is rapidly eliminated via the kidney. The therapeutic use of B-complex vitamins is mostly limited to hypovitaminoses or similar conditions, but, as they are generally very safe, they have also been examined in other pathological conditions. Nicotinic acid, a form of vitamin B3, is the only exception because it is a known hypolipidemic agent in gram doses. The article also sums up: (i) the current methods for detection of the vitamins of the B-complex in biological fluids; (ii) the food and other sources of these vitamins including the effect of common processing and storage methods on their content; and (iii) their physiological function.
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Abstract
Flavin-dependent enzymes catalyze a wide variety of biological reactions that are important for all types of living organisms. Knowledge gained from studying the chemistry and biological functions of flavins and flavin-dependent enzymes has continuously made significant contributions to the development of the fields of enzymology and metabolism from the 1970s until now. The enzymes have been applied in various applications such as use as biocatalysts in synthetic processes for the chemical and pharmaceutical industries or in the biodetoxification and bioremediation of toxic or unwanted compounds, and as biosensors or biodetection tools for quantifying various agents of interest. Many flavin-dependent enzymes are also prime targets for drug development. Based on their reaction mechanisms, they can be classified into five categories: oxidase, dehydrogenase, monooxygenase, reductase, and redox neutral flavin-dependent enzymes. In this chapter, the general properties of flavin-dependent enzymes and the nature of their chemical reactions are discussed, along with their practical applications.
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Sepúlveda Cisternas I, Salazar JC, García-Angulo VA. Overview on the Bacterial Iron-Riboflavin Metabolic Axis. Front Microbiol 2018; 9:1478. [PMID: 30026736 PMCID: PMC6041382 DOI: 10.3389/fmicb.2018.01478] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 06/13/2018] [Indexed: 01/10/2023] Open
Abstract
Redox reactions are ubiquitous in biological processes. Enzymes involved in redox metabolism often use cofactors in order to facilitate electron-transfer reactions. Common redox cofactors include micronutrients such as vitamins and metals. By far, while iron is the main metal cofactor, riboflavin is the most important organic cofactor. Notably, the metabolism of iron and riboflavin seem to be intrinsically related across life kingdoms. In bacteria, iron availability influences expression of riboflavin biosynthetic genes. There is documented evidence for riboflavin involvement in surpassing iron-restrictive conditions in some species. This is probably achieved through increase in iron bioavailability by reduction of extracellular iron, improvement of iron uptake pathways and boosting hemolytic activity. In some cases, riboflavin may also work as replacement of iron as enzyme cofactor. In addition, riboflavin is involved in dissimilatory iron reduction during extracellular respiration by some species. The main direct metabolic relationships between riboflavin and iron in bacterial physiology are reviewed here.
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Affiliation(s)
- Ignacio Sepúlveda Cisternas
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | - Juan C Salazar
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | - Víctor A García-Angulo
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
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Rodionova IA, Vetting MW, Li X, Almo SC, Osterman AL, Rodionov DA. A novel bifunctional transcriptional regulator of riboflavin metabolism in Archaea. Nucleic Acids Res 2017; 45:3785-3799. [PMID: 28073944 PMCID: PMC5397151 DOI: 10.1093/nar/gkw1331] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 12/20/2016] [Indexed: 12/11/2022] Open
Abstract
Riboflavin (vitamin B2) is the precursor of flavin mononucleotide (FMN) and flavin adenine dinucleotide, which are essential coenzymes in all free-living organisms. Riboflavin biosynthesis in many Bacteria but not in Archaea is controlled by FMN-responsive riboswitches. We identified a novel bifunctional riboflavin kinase/regulator (RbkR), which controls riboflavin biosynthesis and transport genes in major lineages of Crenarchaeota, Euryarchaeota and Thaumarchaeota. RbkR proteins are composed of the riboflavin kinase domain and a DNA-binding winged helix-turn-helix-like domain. Using comparative genomics, we predicted RbkR operator sites and reconstructed RbkR regulons in 94 archaeal genomes. While the identified RbkR operators showed significant variability between archaeal lineages, the conserved core of RbkR regulons includes riboflavin biosynthesis genes, known/predicted vitamin uptake transporters and the rbkR gene. The DNA motifs and CTP-dependent riboflavin kinase activity of two RbkR proteins were experimentally validated in vitro. The DNA binding activity of RbkR was stimulated by CTP and suppressed by FMN, a product of riboflavin kinase. The crystallographic structure of RbkR from Thermoplasma acidophilum was determined in complex with CTP and its DNA operator revealing key residues for operator and ligand recognition. Overall, this study contributes to our understanding of metabolic and regulatory networks for vitamin homeostasis in Archaea.
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Affiliation(s)
- Irina A Rodionova
- Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Matthew W Vetting
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Xiaoqing Li
- Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Steven C Almo
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Andrei L Osterman
- Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Dmitry A Rodionov
- Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, CA 92037, USA.,A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, 127051 Russia
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Sarge S, Haase I, Illarionov B, Laudert D, Hohmann HP, Bacher A, Fischer M. Catalysis of an Essential Step in Vitamin B2Biosynthesis by a Consortium of Broad Spectrum Hydrolases. Chembiochem 2015; 16:2466-9. [DOI: 10.1002/cbic.201500352] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Indexed: 11/10/2022]
Affiliation(s)
- Sonja Sarge
- Hamburg School of Food Science; Institute of Food Chemistry; University of Hamburg; Grindelallee 117 20146 Hamburg Germany
| | - Ilka Haase
- Hamburg School of Food Science; Institute of Food Chemistry; University of Hamburg; Grindelallee 117 20146 Hamburg Germany
| | - Boris Illarionov
- Hamburg School of Food Science; Institute of Food Chemistry; University of Hamburg; Grindelallee 117 20146 Hamburg Germany
| | - Dietmar Laudert
- DSM Nutritional Products; P. O. Box 2676 4002 Basel Switzerland
| | | | - Adelbert Bacher
- Hamburg School of Food Science; Institute of Food Chemistry; University of Hamburg; Grindelallee 117 20146 Hamburg Germany
| | - Markus Fischer
- Hamburg School of Food Science; Institute of Food Chemistry; University of Hamburg; Grindelallee 117 20146 Hamburg Germany
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Bacher A, Illarionov B, Eisenreich W, Fischer M. A roadmap to the isotopolog space of flavocoenzymes. Methods Mol Biol 2014; 1146:65-78. [PMID: 24764088 DOI: 10.1007/978-1-4939-0452-5_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Flavocoenzymes with selective or universal stable isotope labeling are important tools for the investigation of flavoproteins using a variety of spectroscopic methods. Numerous selectively labeled flavin isotopologs can be generated by the combined application of chemical synthesis and in vitro biotransformation using commercially available enzymes and/or recombinant riboflavin biosynthesis enzymes. Notably, the complex reaction sequences can be rapidly carried out using enzyme-assisted one-pot reaction strategies.
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Affiliation(s)
- Adelbert Bacher
- Department of Chemistry, Organic Chemistry & Biochemistry, Technische Universität München, Lichtenbergstraße 4, 85748 Garching, Munich, Germany,
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Haase I, Gräwert T, Illarionov B, Bacher A, Fischer M. Recent advances in riboflavin biosynthesis. Methods Mol Biol 2014; 1146:15-40. [PMID: 24764086 DOI: 10.1007/978-1-4939-0452-5_2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Riboflavin is biosynthesized from GTP and ribulose 5-phosphate. Whereas the early reactions conducing to 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione 5'-phosphate show significant taxonomic variation, the subsequent reaction steps are universal in all taxonomic kingdoms. With the exception of a hitherto elusive phosphatase, all enzymes of the pathway have been characterized in some detail at the structural and mechanistic level. Some of the pathway enzymes (GTP cycloyhdrolase II, 3,4-dihydroxy-2-butanone 4-phosphate synthase, riboflavin synthase) have exceptionally complex reaction mechanisms. The commercial production of the vitamin is now entirely based on highly productive fermentation processes. Due to their absence in animals, the pathway enzymes are potential targets for the development of novel anti-infective drugs.
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Affiliation(s)
- Ilka Haase
- Hamburg School of Food Science, Institute of Food Chemistry, University of Hamburg, Grindelallee 117, 20146, Hamburg, Germany
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10
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Paulus B, Illarionov B, Nohr D, Roellinger G, Kacprzak S, Fischer M, Weber S, Bacher A, Schleicher E. One Protein, Two Chromophores: Comparative Spectroscopic Characterization of 6,7-Dimethyl-8-ribityllumazine and Riboflavin Bound to Lumazine Protein. J Phys Chem B 2014; 118:13092-105. [DOI: 10.1021/jp507618f] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Bernd Paulus
- Institute
of Physical Chemistry, Albert-Ludwigs-University Freiburg, Albertstrasse
21, 79104 Freiburg, Germany
| | - Boris Illarionov
- Institute for Biochemistry & Food Chemistry, University of Hamburg, Bundesstrasse 45, 20146 Hamburg, Germany
| | - Daniel Nohr
- Institute
of Physical Chemistry, Albert-Ludwigs-University Freiburg, Albertstrasse
21, 79104 Freiburg, Germany
| | - Guillaume Roellinger
- Institute
of Physical Chemistry, Albert-Ludwigs-University Freiburg, Albertstrasse
21, 79104 Freiburg, Germany
| | - Sylwia Kacprzak
- Institute
of Physical Chemistry, Albert-Ludwigs-University Freiburg, Albertstrasse
21, 79104 Freiburg, Germany
| | - Markus Fischer
- Institute for Biochemistry & Food Chemistry, University of Hamburg, Bundesstrasse 45, 20146 Hamburg, Germany
| | - Stefan Weber
- Institute
of Physical Chemistry, Albert-Ludwigs-University Freiburg, Albertstrasse
21, 79104 Freiburg, Germany
| | - Adelbert Bacher
- Institute for Biochemistry & Food Chemistry, University of Hamburg, Bundesstrasse 45, 20146 Hamburg, Germany
- Chemistry
Department, Technical University Munich, Lichtenbergstrasse 4, 85748 Garching, Germany
| | - Erik Schleicher
- Institute
of Physical Chemistry, Albert-Ludwigs-University Freiburg, Albertstrasse
21, 79104 Freiburg, Germany
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Serer MI, Bonomi HR, Guimarães BG, Rossi RC, Goldbaum FA, Klinke S. Crystallographic and kinetic study of riboflavin synthase from Brucella abortus, a chemotherapeutic target with an enhanced intrinsic flexibility. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2014; 70:1419-34. [PMID: 24816110 PMCID: PMC4014124 DOI: 10.1107/s1399004714005161] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 03/06/2014] [Indexed: 11/11/2022]
Abstract
Riboflavin synthase (RS) catalyzes the last step of riboflavin biosynthesis in microorganisms and plants, which corresponds to the dismutation of two molecules of 6,7-dimethyl-8-ribityllumazine to yield one molecule of riboflavin and one molecule of 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione. Owing to the absence of this enzyme in animals and the fact that most pathogenic bacteria show a strict dependence on riboflavin biosynthesis, RS has been proposed as a potential target for antimicrobial drug development. Eubacterial, fungal and plant RSs assemble as homotrimers lacking C3 symmetry. Each monomer can bind two substrate molecules, yet there is only one active site for the whole enzyme, which is located at the interface between two neighbouring chains. This work reports the crystallographic structure of RS from the pathogenic bacterium Brucella abortus (the aetiological agent of the disease brucellosis) in its apo form, in complex with riboflavin and in complex with two different product analogues, being the first time that the structure of an intact RS trimer with bound ligands has been solved. These crystal models support the hypothesis of enhanced flexibility in the particle and also highlight the role of the ligands in assembling the unique active site. Kinetic and binding studies were also performed to complement these findings. The structural and biochemical information generated may be useful for the rational design of novel RS inhibitors with antimicrobial activity.
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Affiliation(s)
- María I. Serer
- Fundación Instituto Leloir, IIBBA–CONICET, Avenida Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
| | - Hernán R. Bonomi
- Fundación Instituto Leloir, IIBBA–CONICET, Avenida Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
| | - Beatriz G. Guimarães
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin BP 48, 91192 Gif-sur-Yvette CEDEX, France
| | - Rolando C. Rossi
- Instituto de Química y Fisicoquímica Biológicas y Departamento de Química Biológica, IQUIFIB–UBA–CONICET, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, C1113AAD Buenos Aires, Argentina
| | - Fernando A. Goldbaum
- Fundación Instituto Leloir, IIBBA–CONICET, Avenida Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
| | - Sebastián Klinke
- Fundación Instituto Leloir, IIBBA–CONICET, Avenida Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
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Haase I, Sarge S, Illarionov B, Laudert D, Hohmann HP, Bacher A, Fischer M. Enzymes from the Haloacid Dehalogenase (HAD) Superfamily Catalyse the Elusive Dephosphorylation Step of Riboflavin Biosynthesis. Chembiochem 2013; 14:2272-5. [DOI: 10.1002/cbic.201300544] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Indexed: 11/09/2022]
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13
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Shankar M, Wilbanks SM, Nakatani Y, Monk BC, Tyndall JDA. Catalysis product captured in lumazine synthase from the fungal pathogenCandida glabrata. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2013; 69:1580-6. [DOI: 10.1107/s0907444913010949] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 04/23/2013] [Indexed: 02/05/2023]
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Hover BM, Loksztejn A, Ribeiro AA, Yokoyama K. Identification of a cyclic nucleotide as a cryptic intermediate in molybdenum cofactor biosynthesis. J Am Chem Soc 2013; 135:7019-32. [PMID: 23627491 PMCID: PMC3777439 DOI: 10.1021/ja401781t] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The molybdenum cofactor (Moco) is a redox cofactor found in all kingdoms of life, and its biosynthesis is essential for survival of many organisms, including humans. The first step of Moco biosynthesis is a unique transformation of guanosine 5'-triphosphate (GTP) into cyclic pyranopterin monophosphate (cPMP). In bacteria, MoaA and MoaC catalyze this transformation, although the specific functions of these enzymes were not fully understood. Here, we report the first isolation and structural characterization of a product of MoaA. This molecule was isolated under anaerobic conditions from a solution of MoaA incubated with GTP, S-adenosyl-L-methionine, and sodium dithionite in the absence of MoaC. Structural characterization by chemical derivatization, MS, and NMR spectroscopy suggested the structure of this molecule to be (8S)-3',8-cyclo-7,8-dihydroguanosine 5'-triphosphate (3',8-cH2GTP). The isolated 3',8-cH2GTP was converted to cPMP by MoaC or its human homologue, MOCS1B, with high specificities (Km < 0.060 μM and 0.79 ± 0.24 μM for MoaC and MOCS1B, respectively), suggesting the physiological relevance of 3',8-cH2GTP. These observations, in combination with some mechanistic studies of MoaA, unambiguously demonstrate that MoaA catalyzes a unique radical C-C bond formation reaction and that, in contrast to previous proposals, MoaC plays a major role in the complex rearrangement to generate the pyranopterin ring.
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Affiliation(s)
- Bradley M. Hover
- Department of Biochemistry, Duke University Medical Center, Durham, NC, 27710
| | - Anna Loksztejn
- Department of Biochemistry, Duke University Medical Center, Durham, NC, 27710
| | - Anthony A. Ribeiro
- Duke NMR Spectroscopy Center and Department of Radiology, Duke University Medical Center, Durham, NC, 27710
| | - Kenichi Yokoyama
- Department of Biochemistry, Duke University Medical Center, Durham, NC, 27710
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15
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Maruta T, Yoshimoto T, Ito D, Ogawa T, Tamoi M, Yoshimura K, Shigeoka S. An Arabidopsis FAD pyrophosphohydrolase, AtNUDX23, is involved in flavin homeostasis. PLANT & CELL PHYSIOLOGY 2012; 53:1106-16. [PMID: 22505691 DOI: 10.1093/pcp/pcs054] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Although flavins, riboflavin (RF), FMN and FAD, are essential for primary and secondary metabolism in plants, the metabolic regulation of flavins is still largely unknown. Recently, we found that an Arabidopsis Nudix hydrolase, AtNUDX23, has FAD pyrophosphohydrolase activity and is distributed in plastids. Levels of RF and FAD but not FMN in Arabidopsis leaves significantly increased under continuous light and decreased in the dark. The transcript levels of AtNUDX23 as well as genes involved in flavin metabolism (AtFADS, AtRibF1, AtRibF2, AtFMN/FHy, LS and AtRibA) significantly increased under continuous light. The pyrophosphohydrolase activity toward FAD was enhanced in AtNUDX23-overexpressing (OX-NUDX23) plants and reduced in AtNUDX23-suppressed (KD-nudx23) plants, compared with the control plants. Interestingly intracellular levels of RF, FMN and FAD significantly decreased in not only OX-NUDX23 but also KD-nudx23 plants. The transcript levels of the flavin metabolic genes also decreased in both plants. Similarly, the increase in intracellular levels on treatment with flavins caused a reduction in the transcript levels of genes involved in flavin metabolism. These results suggest that negative feedback regulation of the metabolism of flavins through the hydrolysis of FAD by AtNUDX23 in plastids is involved in flavin homeostasis in plant cells.
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Affiliation(s)
- Takanori Maruta
- Department of Advanced Bioscience, Faculty of Agriculture, Kinki University, Nakamachi, Nara, 631-8505 Japan
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16
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Siddaramappa S, Challacombe JF, DeCastro RE, Pfeiffer F, Sastre DE, Giménez MI, Paggi RA, Detter JC, Davenport KW, Goodwin LA, Kyrpides N, Tapia R, Pitluck S, Lucas S, Woyke T, Maupin-Furlow JA. A comparative genomics perspective on the genetic content of the alkaliphilic haloarchaeon Natrialba magadii ATCC 43099T. BMC Genomics 2012; 13:165. [PMID: 22559199 PMCID: PMC3403918 DOI: 10.1186/1471-2164-13-165] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 05/04/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Natrialba magadii is an aerobic chemoorganotrophic member of the Euryarchaeota and is a dual extremophile requiring alkaline conditions and hypersalinity for optimal growth. The genome sequence of Nab. magadii type strain ATCC 43099 was deciphered to obtain a comprehensive insight into the genetic content of this haloarchaeon and to understand the basis of some of the cellular functions necessary for its survival. RESULTS The genome of Nab. magadii consists of four replicons with a total sequence of 4,443,643 bp and encodes 4,212 putative proteins, some of which contain peptide repeats of various lengths. Comparative genome analyses facilitated the identification of genes encoding putative proteins involved in adaptation to hypersalinity, stress response, glycosylation, and polysaccharide biosynthesis. A proton-driven ATP synthase and a variety of putative cytochromes and other proteins supporting aerobic respiration and electron transfer were encoded by one or more of Nab. magadii replicons. The genome encodes a number of putative proteases/peptidases as well as protein secretion functions. Genes encoding putative transcriptional regulators, basal transcription factors, signal perception/transduction proteins, and chemotaxis/phototaxis proteins were abundant in the genome. Pathways for the biosynthesis of thiamine, riboflavin, heme, cobalamin, coenzyme F420 and other essential co-factors were deduced by in depth sequence analyses. However, approximately 36% of Nab. magadii protein coding genes could not be assigned a function based on Blast analysis and have been annotated as encoding hypothetical or conserved hypothetical proteins. Furthermore, despite extensive comparative genomic analyses, genes necessary for survival in alkaline conditions could not be identified in Nab. magadii. CONCLUSIONS Based on genomic analyses, Nab. magadii is predicted to be metabolically versatile and it could use different carbon and energy sources to sustain growth. Nab. magadii has the genetic potential to adapt to its milieu by intracellular accumulation of inorganic cations and/or neutral organic compounds. The identification of Nab. magadii genes involved in coenzyme biosynthesis is a necessary step toward further reconstruction of the metabolic pathways in halophilic archaea and other extremophiles. The knowledge gained from the genome sequence of this haloalkaliphilic archaeon is highly valuable in advancing the applications of extremophiles and their enzymes.
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Affiliation(s)
| | - Jean F Challacombe
- DOE Joint Genome Institute, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Rosana E DeCastro
- Instituto de Investigaciones Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3250 4to Nivel, Mar del Plata, 7600, Argentina
| | - Friedhelm Pfeiffer
- Department of Membrane Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152, Martinsried, Germany
| | - Diego E Sastre
- Instituto de Investigaciones Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3250 4to Nivel, Mar del Plata, 7600, Argentina
| | - María I Giménez
- Instituto de Investigaciones Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3250 4to Nivel, Mar del Plata, 7600, Argentina
| | - Roberto A Paggi
- Instituto de Investigaciones Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3250 4to Nivel, Mar del Plata, 7600, Argentina
| | - John C Detter
- DOE Joint Genome Institute, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Karen W Davenport
- DOE Joint Genome Institute, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Lynne A Goodwin
- DOE Joint Genome Institute, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Nikos Kyrpides
- DOE Joint Genome Institute, Walnut Creek, CA, 94598, USA
| | - Roxanne Tapia
- DOE Joint Genome Institute, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Samuel Pitluck
- DOE Joint Genome Institute, Walnut Creek, CA, 94598, USA
| | - Susan Lucas
- DOE Joint Genome Institute, Walnut Creek, CA, 94598, USA
| | - Tanja Woyke
- DOE Joint Genome Institute, Walnut Creek, CA, 94598, USA
| | - Julie A Maupin-Furlow
- Department of Microbiology and Cell Science, University of Florida, Bldg. 981, Museum Rd., P.O. Box 110700, Gainesville, FL, 32611-0700, USA
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