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Centeno-Leija S, Espinosa-Barrera L, Velazquez-Cruz B, Cárdenas-Conejo Y, Virgen-Ortíz R, Valencia-Cruz G, Saenz RA, Marín-Tovar Y, Gómez-Manzo S, Hernández-Ochoa B, Rocha-Ramirez LM, Zataraín-Palacios R, Osuna-Castro JA, López-Munguía A, Serrano-Posada H. Mining for novel cyclomaltodextrin glucanotransferases unravels the carbohydrate metabolism pathway via cyclodextrins in Thermoanaerobacterales. Sci Rep 2022; 12:730. [PMID: 35031648 PMCID: PMC8760340 DOI: 10.1038/s41598-021-04569-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 12/20/2021] [Indexed: 11/21/2022] Open
Abstract
Carbohydrate metabolism via cyclodextrins (CM-CD) is an uncommon starch-converting pathway that thoroughly depends on extracellular cyclomaltodextrin glucanotransferases (CGTases) to transform the surrounding starch substrate to α-(1,4)-linked oligosaccharides and cyclodextrins (CDs). The CM-CD pathway has emerged as a convenient microbial adaptation to thrive under extreme temperatures, as CDs are functional amphipathic toroids with higher heat-resistant values than linear dextrins. Nevertheless, although the CM-CD pathway has been described in a few mesophilic bacteria and archaea, it remains obscure in extremely thermophilic prokaryotes (Topt ≥ 70 °C). Here, a new monophyletic group of CGTases with an exceptional three-domain ABC architecture was detected by (meta)genome mining of extremely thermophilic Thermoanaerobacterales living in a wide variety of hot starch-poor environments on Earth. Functional studies of a representative member, CldA, showed a maximum activity in a thermoacidophilic range (pH 4.0 and 80 °C) with remarkable product diversification that yielded a mixture of α:β:γ-CDs (34:62:4) from soluble starch, as well as G3-G7 linear dextrins and fermentable sugars as the primary products. Together, comparative genomics and predictive functional analysis, combined with data of the functionally characterized key proteins of the gene clusters encoding CGTases, revealed the CM-CD pathway in Thermoanaerobacterales and showed that it is involved in the synthesis, transportation, degradation, and metabolic assimilation of CDs.
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Affiliation(s)
- Sara Centeno-Leija
- Consejo Nacional de Ciencia y Tecnología, Laboratorio de Biología Sintética, Estructural y Molecular, Laboratorio de Agrobiotecnología, Tecnoparque CLQ, Universidad de Colima, Carretera Los Limones-Loma de Juárez, 28627, Colima, Colima, Mexico.
| | - Laura Espinosa-Barrera
- Laboratorio de Biología Sintética, Estructural y Molecular, Laboratorio de Agrobiotecnología, Tecnoparque CLQ, Universidad de Colima, Carretera Los Limones-Loma de Juárez, 28627, Colima, Colima, Mexico
| | - Beatriz Velazquez-Cruz
- Laboratorio de Biología Sintética, Estructural y Molecular, Laboratorio de Agrobiotecnología, Tecnoparque CLQ, Universidad de Colima, Carretera Los Limones-Loma de Juárez, 28627, Colima, Colima, Mexico
| | - Yair Cárdenas-Conejo
- Consejo Nacional de Ciencia y Tecnología, Laboratorio de Biología Sintética, Estructural y Molecular, Laboratorio de Agrobiotecnología, Tecnoparque CLQ, Universidad de Colima, Carretera Los Limones-Loma de Juárez, 28627, Colima, Colima, Mexico
| | - Raúl Virgen-Ortíz
- Laboratorio de Biología Sintética, Estructural y Molecular, Laboratorio de Agrobiotecnología, Tecnoparque CLQ, Universidad de Colima, Carretera Los Limones-Loma de Juárez, 28627, Colima, Colima, Mexico
| | - Georgina Valencia-Cruz
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Avenida 25 de julio 965, Colonia Villa de San Sebastián, 28045, Colima, Colima, Mexico
| | - Roberto A Saenz
- Facultad de Ciencias, Universidad de Colima, Bernal Díaz del Castillo 340, 28045, Colima, Colima, Mexico
| | - Yerli Marín-Tovar
- Laboratorio de Bioquímica Estructural, Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Colonia Chamilpa, 62210, Cuernavaca, Mexico
| | - Saúl Gómez-Manzo
- Laboratorio de Bioquímica Genética, Instituto Nacional de Pediatría, Secretaría de Salud, 04530, Mexico City, Mexico
| | - Beatriz Hernández-Ochoa
- Laboratorio de Inmunoquímica y Biología Celular, Hospital Infantil de México Federico Gómez, Secretaría de Salud, 06720, Mexico City, Mexico
| | - Luz María Rocha-Ramirez
- Unidad de Investigación en Enfermedades Infecciosas, Hospital Infantil de México Federico Gómez, Dr. Márquez No. 162, Colonia Doctores, 06720, Delegación Cuauhtémoc, Mexico
| | - Rocío Zataraín-Palacios
- Escuela de Medicina General, Universidad José Martí, Bosques del Decán 351, 28089, Colima, Colima, México
| | - Juan A Osuna-Castro
- Facultad de Ciencias Biológicas y Agropecuarias, Universidad de Colima, Autopista Colima-Manzanillo, 28100, Tecomán, Colima, Mexico
| | - Agustín López-Munguía
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Colonia Chamilpa, 62210, Cuernavaca, Morelos, Mexico
| | - Hugo Serrano-Posada
- Consejo Nacional de Ciencia y Tecnología, Laboratorio de Biología Sintética, Estructural y Molecular, Laboratorio de Agrobiotecnología, Tecnoparque CLQ, Universidad de Colima, Carretera Los Limones-Loma de Juárez, 28627, Colima, Colima, Mexico.
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β-NAD as a building block in natural product biosynthesis. Nature 2021; 600:754-758. [PMID: 34880494 DOI: 10.1038/s41586-021-04214-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 11/04/2021] [Indexed: 01/07/2023]
Abstract
ABSTRATCT β-Nicotinamide adenine dinucleotide (β-NAD) is a pivotal metabolite for all living organisms and functions as a diffusible electron acceptor and carrier in the catabolic arms of metabolism1,2. Furthermore, β-NAD is involved in diverse epigenetic, immunological and stress-associated processes, where it is known to be sacrificially utilized as an ADP-ribosyl donor for protein and DNA modifications, or the generation of cell-signalling molecules3,4. Here we report the function of β-NAD in secondary metabolite biosynthetic pathways, in which the nicotinamide dinucleotide framework is heavily decorated and serves as a building block for the assembly of a novel class of natural products. The gatekeeping enzyme of the discovered pathway (SbzP) catalyses a pyridoxal phosphate-dependent [3+2]-annulation reaction between β-NAD and S-adenosylmethionine, generating a 6-azatetrahydroindane scaffold. Members of this novel family of β-NAD-tailoring enzymes are widely distributed in the bacterial kingdom and are encoded in diverse biosynthetic gene clusters. The findings of this work set the stage for the discovery and exploitation of β-NAD-derived natural products.
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Alali A, Zhang L, Li J, Zuo C, Wassouf D, Yan X, Schwarzer P, Günther S, Einsle O, Bechthold A. Biosynthesis of the Tricyclic Aromatic Type II Polyketide Rishirilide: New Potential Third Ring Oxygenation after Three Cyclization Steps. Mol Biotechnol 2021; 63:502-514. [PMID: 33763824 PMCID: PMC8093152 DOI: 10.1007/s12033-021-00314-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 03/05/2021] [Indexed: 11/30/2022]
Abstract
Rishirilides are a group of PKS II secondary metabolites produced by Streptomyces bottropensis Gö C4/4. Biosynthetic studies in the past have elucidated early and late steps of rishirilide biosynthesis. This work is aiming to solve the remaining steps in the rishirilide biosynthesis. Inactivation of the cyclase gene rslC3 in Streptomyces bottropensis resulted in an interruption of rishirilide production. Instead, accumulation of the tricyclic aromatic galvaquinones was observed. Similar results were observed after deletion of rslO4. Closer inspection into RslO4 crystal structure in addition to site-directed mutagenesis and molecular dynamic simulations revealed that RslO4 might be responsible for quinone formation on the third ring. The RslO1 three-dimensional structure shows a high similarity to FMN-dependent luciferase-like monooxygenases such as the epoxy-forming MsnO8 which acts with the flavin reductase MsnO3 in mensacarcin biosynthesis in the same strain. The high sequence similarity between RslO2 and MsnO3 suggests that RslO2 provides RslO1 with reduced FMN to form an epoxide that serves as substrate for RslO5.
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Affiliation(s)
- Ahmad Alali
- Institute of Pharmaceutical Biology and Biotechnology, Albert-Ludwigs-Universität, Stefan-Meier-Straße 19, 79104, Freiburg, Germany
| | - Lin Zhang
- Institute of Biochemistry, Albert-Ludwigs-Universität, Albertstr 21, 79104, Freiburg, Germany
| | - Jianyu Li
- Institute of Pharmaceutical Bioinformatics, Albert-Ludwigs-Universität, Hermann-Herder-Str 9, 79104, Freiburg, Germany
| | - Chijian Zuo
- Institute of Pharmaceutical Biology and Biotechnology, Albert-Ludwigs-Universität, Stefan-Meier-Straße 19, 79104, Freiburg, Germany
| | - Dimah Wassouf
- Institute of Pharmaceutical Biology and Biotechnology, Albert-Ludwigs-Universität, Stefan-Meier-Straße 19, 79104, Freiburg, Germany
| | - Xiaohui Yan
- Institute of Pharmaceutical Biology and Biotechnology, Albert-Ludwigs-Universität, Stefan-Meier-Straße 19, 79104, Freiburg, Germany
| | - Philipp Schwarzer
- Institute of Pharmaceutical Biology and Biotechnology, Albert-Ludwigs-Universität, Stefan-Meier-Straße 19, 79104, Freiburg, Germany
| | - Stefan Günther
- Institute of Pharmaceutical Bioinformatics, Albert-Ludwigs-Universität, Hermann-Herder-Str 9, 79104, Freiburg, Germany
| | - Oliver Einsle
- Institute of Biochemistry, Albert-Ludwigs-Universität, Albertstr 21, 79104, Freiburg, Germany
| | - Andreas Bechthold
- Institute of Pharmaceutical Biology and Biotechnology, Albert-Ludwigs-Universität, Stefan-Meier-Straße 19, 79104, Freiburg, Germany.
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Lee BM, Harold LK, Almeida DV, Afriat-Jurnou L, Aung HL, Forde BM, Hards K, Pidot SJ, Ahmed FH, Mohamed AE, Taylor MC, West NP, Stinear TP, Greening C, Beatson SA, Nuermberger EL, Cook GM, Jackson CJ. Predicting nitroimidazole antibiotic resistance mutations in Mycobacterium tuberculosis with protein engineering. PLoS Pathog 2020; 16:e1008287. [PMID: 32032366 PMCID: PMC7032734 DOI: 10.1371/journal.ppat.1008287] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 02/20/2020] [Accepted: 12/16/2019] [Indexed: 12/21/2022] Open
Abstract
Our inability to predict which mutations could result in antibiotic resistance has made it difficult to rapidly identify the emergence of resistance, identify pre-existing resistant populations, and manage our use of antibiotics to effectively treat patients and prevent or slow the spread of resistance. Here we investigated the potential for resistance against the new antitubercular nitroimidazole prodrugs pretomanid and delamanid to emerge in Mycobacterium tuberculosis, the causative agent of tuberculosis (TB). Deazaflavin-dependent nitroreductase (Ddn) is the only identified enzyme within M. tuberculosis that activates these prodrugs, via an F420H2-dependent reaction. We show that the native menaquinone-reductase activity of Ddn is essential for emergence from hypoxia, which suggests that for resistance to spread and pose a threat to human health, the native activity of Ddn must be at least partially retained. We tested 75 unique mutations, including all known sequence polymorphisms identified among ~15,000 sequenced M. tuberculosis genomes. Several mutations abolished pretomanid and delamanid activation in vitro, without causing complete loss of the native activity. We confirmed that a transmissible M. tuberculosis isolate from the hypervirulent Beijing family already possesses one such mutation and is resistant to pretomanid, before being exposed to the drug. Notably, delamanid was still effective against this strain, which is consistent with structural analysis that indicates delamanid and pretomanid bind to Ddn differently. We suggest that the mutations identified in this work be monitored for informed use of delamanid and pretomanid treatment and to slow the emergence of resistance.
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Affiliation(s)
- Brendon M. Lee
- Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Liam K. Harold
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Deepak V. Almeida
- Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Livnat Afriat-Jurnou
- Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory, Australia
- MIGAL, Galilee Research Institute, Kiryat Shmona, Israel
- Faculty of Sciences and Technology, Tel-Hai Academic College, Upper Galilee, Israel
| | - Htin Lin Aung
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Brian M. Forde
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Kiel Hards
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Sacha J. Pidot
- Department of Microbiology and Immunology, University of Melbourne, Melbourne, Victoria, Australia
| | - F. Hafna Ahmed
- Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory, Australia
| | - A. Elaaf Mohamed
- Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Matthew C. Taylor
- Land and Water Flagship, The Commonwealth Scientific and Industrial Organisation, Canberra, Australian Capital Territory, Australia
| | - Nicholas P. West
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Timothy P. Stinear
- Department of Microbiology and Immunology, University of Melbourne, Melbourne, Victoria, Australia
| | - Chris Greening
- Land and Water Flagship, The Commonwealth Scientific and Industrial Organisation, Canberra, Australian Capital Territory, Australia
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
| | - Scott A. Beatson
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Eric L. Nuermberger
- Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Gregory M. Cook
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Colin J. Jackson
- Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory, Australia
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Recombinant Aflatoxin-Degrading F 420H 2-Dependent Reductase from Mycobacterium smegmatis Protects Mammalian Cells from Aflatoxin Toxicity. Toxins (Basel) 2019; 11:toxins11050259. [PMID: 31072027 PMCID: PMC6563500 DOI: 10.3390/toxins11050259] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 04/30/2019] [Accepted: 05/06/2019] [Indexed: 11/17/2022] Open
Abstract
Aflatoxins are carcinogenic secondary metabolites of fungi that contaminate many staple crops and foods. Aflatoxin contamination is a worldwide problem, especially in developing countries, posing health hazards, e.g., causing aflatoxicosis and hepatocellular carcinoma, and even death. Biological solutions for aflatoxin detoxification are environmentally friendly and a cheaper alternative than chemical methods. The aims of the current study were to investigate: (1) the ability of MSMEG_5998, an aflatoxin-degrading F420H2-dependent reductase from Mycobacterium smegmatis, to degrade aflatoxin B1 (AFB1) and reduce AFB1-caused damage in HepG2 cell culture model; and (2) whether a thioredoxin (Trx) linkage of MSMEG_5998 enhanced the enzyme activity. We show that Trx-linked MSMEG_5998 degraded 63% AFB1 and native MSMEG_5998 degraded 31% after 4 h at 22 °C, indicating that the Trx-linked enzyme had a better AFB1-degrading ability. In a HepG2 cell culture model, Trx-linked MSMEG_5998 reduced DNA damage and p53-mediated apoptosis caused by AFB1 to a greater extent than the native enzyme. These findings suggest that Trx-linked MSMEG_5998 could potentially be developed to protect the liver from AFB1 damage, or as a candidate protein to reduce AFB1-related toxicity in animals.
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Zhang SF, Chen Y, Xie ZX, Zhang H, Lin L, Wang DZ. Unraveling the molecular mechanism of the response to changing ambient phosphorus in the dinoflagellate Alexandrium catenella with quantitative proteomics. J Proteomics 2019; 196:141-149. [PMID: 30414514 DOI: 10.1016/j.jprot.2018.11.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 10/30/2018] [Accepted: 11/05/2018] [Indexed: 10/27/2022]
Abstract
Phosphorus (P) is a key macronutrient limiting cell growth and bloom formation of marine dinoflagellates. Physiological responses to changing ambient P have been investigated in dinoflagellates; however, the molecular mechanisms behind these responses remain limited. Here, we compared the protein expression profiles of a marine dinoflagellate Alexandrium catenella grown in inorganic P-replete, P-deficient, and inorganic- and organic-P resupplied conditions using an iTRAQ-based quantitative proteomic approach. P deficiency inhibited cell growth and enhanced alkaline phosphatase activity (APA) but had no effect on photosynthetic efficiency. After P resupply, the P-deficient cells recovered growth rapidly and APA decreased. Proteins involved in sphingolipid metabolism, organic P utilization, starch and sucrose metabolism, and photosynthesis were up-regulated in the P-deficient cells, while proteins associated with protein synthesis, nutrient assimilation and energy metabolism were down-regulated. The responses of the P-deficient A. catenella to the resupply of organic and inorganic P presented significant differences: more biological processes were enhanced in the organic P-resupplied cells than those in the inorganic P-resupplied cells; A. catenella might directly utilize G-6-P for nucleic acid synthesis through the pentose phosphate pathway. Our results indicate that A. catenella has evolved diverse adaptive strategies to ambient P deficiency and specific mechanisms to utilize dissolved organic P, which might be an important reason resulting in A. catenella bloom in the low inorganic P environment. BIOLOGICAL SIGNIFICANCE: The ability of marine dinoflagellates to utilize different phosphorus (P) species and adapt to ambient P deficiency determines their success in the ocean. In this study, we investigated the response mechanisms of a dinoflagellate Alexandrium catenella to ambient P deficiency, and resupply of inorganic- and organic-P at the proteome level. Our results indicated that A. catenella initiated multiple adaptive strategies to ambient P deficiency, e.g. utilizing nonphospholipids and glycosphingolipids instead of phospholipids, enhancing expression of acid phosphatase to utilize organic P, and reallocating intracellular energy. Proteome responses of the P-deficient A. catenella to resupply of inorganic- and organic-P differed significantly, indicating different utilization pathways of inorganic and organic P, A. catenella might directly utilize low molecular weight organic P, such as G-6-P as both P and carbon sources.
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Affiliation(s)
- Shu-Feng Zhang
- State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, Xiamen, 361102, China
| | - Ying Chen
- State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, Xiamen, 361102, China
| | - Zhang-Xian Xie
- State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, Xiamen, 361102, China
| | - Hao Zhang
- State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, Xiamen, 361102, China
| | - Lin Lin
- State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, Xiamen, 361102, China
| | - Da-Zhi Wang
- State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, Xiamen, 361102, China; Key Laboratory of Marine Ecology & Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
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Reconstructing the evolutionary history of F 420-dependent dehydrogenases. Sci Rep 2018; 8:17571. [PMID: 30514849 PMCID: PMC6279831 DOI: 10.1038/s41598-018-35590-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 08/24/2018] [Indexed: 12/20/2022] Open
Abstract
During the last decade the number of characterized F420-dependent enzymes has significantly increased. Many of these deazaflavoproteins share a TIM-barrel fold and are structurally related to FMN-dependent luciferases and monooxygenases. In this work, we traced the origin and evolutionary history of the F420-dependent enzymes within the luciferase-like superfamily. By a thorough phylogenetic analysis we inferred that the F420-dependent enzymes emerged from a FMN-dependent common ancestor. Furthermore, the data show that during evolution, the family of deazaflavoproteins split into two well-defined groups of enzymes: the F420-dependent dehydrogenases and the F420-dependent reductases. By such event, the dehydrogenases specialized in generating the reduced deazaflavin cofactor, while the reductases employ the reduced F420 for catalysis. Particularly, we focused on investigating the dehydrogenase subfamily and demonstrated that this group diversified into three types of dehydrogenases: the already known F420-dependent glucose-6-phosphate dehydrogenases, the F420-dependent alcohol dehydrogenases, and the sugar-6-phosphate dehydrogenases that were identified in this study. By reconstructing and experimentally characterizing ancestral and extant representatives of F420-dependent dehydrogenases, their biochemical properties were investigated and compared. We propose an evolutionary path for the emergence and diversification of the TIM-barrel fold F420-dependent dehydrogenases subfamily.
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Ichikawa H, Bashiri G, Kelly WL. Biosynthesis of the Thiopeptins and Identification of an F 420H 2-Dependent Dehydropiperidine Reductase. J Am Chem Soc 2018; 140:10749-10756. [PMID: 30118217 PMCID: PMC6193465 DOI: 10.1021/jacs.8b04238] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Thiopeptins are highly decorated thiopeptide antibiotics similar in structure to thiostrepton A and harbor two unusual features. All thiopeptins contain a thioamide, a rare moiety among natural products, and a subset of thiopeptins present with a piperidine in the core macrocycle rather than the more oxidated dehydropiperidine or pyridine rings typically observed in the thiopeptides. Here, we report the identification of the thiopeptin biosynthetic gene ( tpn) cluster in Streptomyces tateyamensis and the gene product, TpnL, which shows sequence similarity to (deaza)flavin-dependent oxidoreductases. Heterologous expression of TpnL in the thiostrepton A producer Streptomyces laurentii led to the production of a piperidine-containing analogue. Binding studies revealed that TpnL preferentially binds the deazaflavin cofactor coenzyme F420, and in vitro reconstitution of TpnL activity confirmed that this enzyme is an F420H2-dependent dehydropiperidine reductase. The identification of TpnL and its activity establishes the basis for the piperidine-containing series a thiopeptides, one of the five main structural groups of this diverse family of antibiotics.
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Affiliation(s)
- Hiro Ichikawa
- School of Chemistry and Biochemistry and the Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Ghader Bashiri
- Laboratory of Structural Biology and Maurice Wilkins Center for Molecular Biodiscovery, School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand
| | - Wendy L. Kelly
- School of Chemistry and Biochemistry and the Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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Oyugi MA, Bashiri G, Baker EN, Johnson-Winters K. Mechanistic insights into F 420-dependent glucose-6-phosphate dehydrogenase using isotope effects and substrate inhibition studies. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017; 1866:387-395. [PMID: 28807886 DOI: 10.1016/j.bbapap.2017.08.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 07/24/2017] [Accepted: 08/03/2017] [Indexed: 01/24/2023]
Abstract
F420-dependent glucose-6-phosphate dehydrogenase (FGD) is involved in the committed step of the pentose phosphate pathway within mycobacteria, where it catalyzes the reaction between glucose-6-phosphate (G6P) and the F420 cofactor to yield 6-phosphogluconolactone and the reduced cofactor, F420H2. Here, we aim to probe the FGD reaction mechanism using dead-end inhibition experiments, as well as solvent and substrate deuterium isotope effects studies. The dead-end inhibition studies performed using citrate as the inhibitor revealed competitive and uncompetitive inhibition patterns for G6P and F420 respectively, thus suggesting a mechanism of ordered addition of substrates in which the F420 cofactor must first bind to FGD before G6P binding. The solvent deuterium isotope effects studies yielded normal solvent kinetic isotope effects (SKIE) on kcat and kcat/Km for both G6P and F420. The proton inventory data yielded a fractionation factor of 0.37, suggesting that the single proton responsible for the observed SKIE is likely donated by Glu109 and protonates the cofactor at position N1. The steady state substrate deuterium isotope effects studies using G6P and G6P-d1 yielded KIE of 1.1 for both kcat and kcat/Km, while the pre-steady state KIE on kobs was 1.4. Because the hydride transferred to C5 of F420 was the one targeted for isotopic substitution, these KIE values provide further evidence to support our previous findings that hydride transfer is likely not rate-limiting in the FGD reaction.
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Affiliation(s)
- Mercy A Oyugi
- Department of Chemistry and Biochemistry, University of Texas at Arlington, TX 76019-0065, United States
| | - Ghader Bashiri
- Laboratory of Structural Biology and Maurice Wilkins Center for Molecular Biodiscovery, School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand
| | - Edward N Baker
- Laboratory of Structural Biology and Maurice Wilkins Center for Molecular Biodiscovery, School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand
| | - Kayunta Johnson-Winters
- Department of Chemistry and Biochemistry, University of Texas at Arlington, TX 76019-0065, United States.
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