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Stare J. Oxidation of Flavin by Molecular Oxygen: Computational Insights into a Possible Radical Mechanism. ACS OMEGA 2024; 9:23431-23441. [PMID: 38854520 PMCID: PMC11154890 DOI: 10.1021/acsomega.4c00307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 04/19/2024] [Accepted: 05/13/2024] [Indexed: 06/11/2024]
Abstract
As a highly electrophilic moiety capable of oxidizing a variety of small organic molecules and biomolecules, flavin is an important prosthetic group in many enzymes. Upon oxidation of the substrate, flavin is converted into its reduced (dihydrogenated) form. The catalytic cycle is completed through oxidation back to the oxidized form, thus restoring the enzyme's oxidizing capability. While it has been firmly established that oxidation of the reduced form of flavin is cast by molecular oxygen, yielding oxidized flavin and hydrogen peroxide, the mechanism of this process is still poorly understood. Herein, we investigate the radical mechanism, which is one of the possible reaction mechanisms, by quantum chemical calculations. Because molecular oxygen exists as a triplet in its electronic ground state, whereas the products are singlets, the reaction is accompanied by hopping between electronic surfaces. We find that the rate-limiting factor of flavin oxidation is likely associated with the change in the spin state of the system. By considering several possible reactions involving flavin and its derivatives in the radical form and by examining the corresponding parts of the potential energy surface in various spin states, we estimate the effective barrier of the kinetically and thermodynamically preferred variant of flavin oxidation to be about 15 kcal/mol in the gas phase and about 7 kcal/mol in a polar (aqueous) environment. This is in agreement with kinetic studies of the corresponding monoamine oxidase enzymes, confirming the radical mechanism as a viable option for flavin regeneration in enzymes.
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Affiliation(s)
- Jernej Stare
- National Institute of Chemistry,Hajdrihova 19, SI-1000 Ljubljana, Slovenia
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2
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Teufel R. Oxygen-transfer reactions by enzymatic flavin-N 5 oxygen adducts-Oxidation is not a must. Curr Opin Chem Biol 2024; 80:102464. [PMID: 38739969 DOI: 10.1016/j.cbpa.2024.102464] [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: 02/29/2024] [Revised: 04/16/2024] [Accepted: 04/17/2024] [Indexed: 05/16/2024]
Abstract
Flavoenzymes catalyze numerous redox reactions including the transfer of an O2-derived oxygen atom to organic substrates, while the other one is reduced to water. Investigation of some of these monooxygenases led to a detailed understanding of their catalytic cycle, which involves the flavin-C4α-(hydro)peroxide as hallmark oxygenating species, and newly discovered flavoprotein monooxygenases were generally assumed to operate similarly. However, discoveries in recent years revealed a broader mechanistic versatility, including enzymes that utilize flavin-N5 oxygen adducts for catalysis in the form of the flavin-N5-(hydro)peroxide and the flavin-N5-oxide species. In this review, I will highlight recent developments in that area, including noncanonical flavoenzymes from natural product biosynthesis and sulfur metabolism that provide first insights into the chemical properties of these species. Remarkably, some enzymes may even combine the flavin-N5-peroxide and the flavin-N5-oxide species for consecutive oxygen-transfers to the same substrate and thereby in essence operate as dioxygenases.
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Affiliation(s)
- Robin Teufel
- Pharmaceutical Biology, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland.
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3
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Quaye JA, Wood KE, Snelgrove C, Ouedraogo D, Gadda G. An active site mutation induces oxygen reactivity in D-arginine dehydrogenase: A case of superoxide diverting protons. J Biol Chem 2024; 300:107381. [PMID: 38762175 PMCID: PMC11193025 DOI: 10.1016/j.jbc.2024.107381] [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: 04/12/2024] [Revised: 05/09/2024] [Accepted: 05/13/2024] [Indexed: 05/20/2024] Open
Abstract
Enzymes are potent catalysts that increase biochemical reaction rates by several orders of magnitude. Flavoproteins are a class of enzymes whose classification relies on their ability to react with molecular oxygen (O2) during catalysis using ionizable active site residues. Pseudomonas aeruginosa D-arginine dehydrogenase (PaDADH) is a flavoprotein that oxidizes D-arginine for P. aeruginosa survival and biofilm formation. The crystal structure of PaDADH reveals the interaction of the glutamate 246 (E246) side chain with the substrate and at least three other active site residues, establishing a hydrogen bond network in the active site. Additionally, E246 likely ionizes to facilitate substrate binding during PaDADH catalysis. This study aimed to investigate how replacing the E246 residue with leucine affects PaDADH catalysis and its ability to react with O2 using steady-state kinetics coupled with pH profile studies. The data reveal a gain of O2 reactivity in the E246L variant, resulting in a reduced flavin semiquinone species and superoxide (O2•-) during substrate oxidation. The O2•- reacts with active site protons, resulting in an observed nonstoichiometric slope of 1.5 in the enzyme's log (kcat/Km) pH profile with D-arginine. Adding superoxide dismutase results in an observed correction of the slope to 1.0. This study demonstrates how O2•- can alter the slopes of limbs in the pH profiles of flavin-dependent enzymes and serves as a model for correcting nonstoichiometric slopes in elucidating reaction mechanisms of flavoproteins.
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Affiliation(s)
- Joanna A Quaye
- Department of Chemistry, Georgia State University, Atlanta, Georgia, USA
| | - Kendall E Wood
- Biology Department, Morehouse College, Atlanta, Georgia, USA
| | - Claire Snelgrove
- The Gwinnett School of Mathematics, Science, and Technology, Lawrenceville, Georgia, USA
| | - Daniel Ouedraogo
- Department of Chemistry, Georgia State University, Atlanta, Georgia, USA
| | - Giovanni Gadda
- Department of Chemistry, Georgia State University, Atlanta, Georgia, USA; Department of Biology, Georgia State University, Atlanta, Georgia, USA; Department of the Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia, USA.
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4
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Höing L, Sowa ST, Toplak M, Reinhardt JK, Jakob R, Maier T, Lill MA, Teufel R. Biosynthesis of the bacterial antibiotic 3,7-dihydroxytropolone through enzymatic salvaging of catabolic shunt products. Chem Sci 2024; 15:7749-7756. [PMID: 38784727 PMCID: PMC11110157 DOI: 10.1039/d4sc01715c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 04/21/2024] [Indexed: 05/25/2024] Open
Abstract
The non-benzenoid aromatic tropone ring is a structural motif of numerous microbial and plant natural products with potent bioactivities. In bacteria, tropone biosynthesis involves early steps of the widespread CoA-dependent phenylacetic acid (paa) catabolon, from which a shunt product is sequestered and surprisingly further utilized as a universal precursor for structurally and functionally diverse tropone derivatives such as tropodithietic acid or (hydroxy)tropolones. Here, we elucidate the biosynthesis of the antibiotic 3,7-dihydroxytropolone in Actinobacteria by in vitro pathway reconstitution using paa catabolic enzymes as well as dedicated downstream tailoring enzymes, including a thioesterase (TrlF) and two flavoprotein monooxygenases (TrlCD and TrlE). We furthermore mechanistically and structurally characterize the multifunctional key enzyme TrlE, which mediates an unanticipated ipso-substitution involving a hydroxylation and subsequent decarboxylation of the CoA-freed side chain, followed by ring oxidation to afford tropolone. This study showcases a remarkably efficient strategy for 3,7-dihydroxytropolone biosynthesis and illuminates the functions of the involved biosynthetic enzymes.
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Affiliation(s)
- Lars Höing
- Pharmaceutical Biology, Department of Pharmaceutical Sciences, University of Basel Klingelbergstrasse 50 4056 Basel Switzerland
| | - Sven T Sowa
- Pharmaceutical Biology, Department of Pharmaceutical Sciences, University of Basel Klingelbergstrasse 50 4056 Basel Switzerland
| | - Marina Toplak
- Hilde-Mangold-Haus (CIBSS), University of Freiburg Habsburgerstrasse 49 79104 Freiburg im Breisgau Germany
| | - Jakob K Reinhardt
- Pharmaceutical Biology, Department of Pharmaceutical Sciences, University of Basel Klingelbergstrasse 50 4056 Basel Switzerland
| | - Roman Jakob
- Biozentrum, University of Basel Spitalstrasse 41 4056 Basel Switzerland
| | - Timm Maier
- Biozentrum, University of Basel Spitalstrasse 41 4056 Basel Switzerland
| | - Markus A Lill
- Computational Pharmacy, Department of Pharmaceutical Sciences, University of Basel Klingelbergstrasse 50 4056 Basel Switzerland
| | - Robin Teufel
- Pharmaceutical Biology, Department of Pharmaceutical Sciences, University of Basel Klingelbergstrasse 50 4056 Basel Switzerland
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5
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Zhang Q, Chen Q, Shaik S, Wang B. Flavin-N5OOH Functions as both a Powerful Nucleophile and a Base in the Superfamily of Flavoenzymes. Angew Chem Int Ed Engl 2024; 63:e202318629. [PMID: 38299700 DOI: 10.1002/anie.202318629] [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: 01/30/2024] [Accepted: 01/31/2024] [Indexed: 02/02/2024]
Abstract
Flavoenzymes can mediate a large variety of oxidation reactions through the activation of oxygen. However, the O2 activation chemistry of flavin enzymes is not yet fully exploited. Normally, the O2 activation occurs at the C4a site of the flavin cofactor, yielding the flavin C4a-(hydro)hydroperoxyl species in monooxygenases or oxidases. Using extensive MD simulations, QM/MM calculations and QM calculations, our studies reveal the formation of the common nucleophilic species, Flavin-N5OOH, in two distinct flavoenzymes (RutA and EncM). Our studies show that Flavin-N5OOH acts as a powerful nucleophile that promotes C-N cleavage of uracil in RutA, and a powerful base in the deprotonation of substrates in EncM. We reason that Flavin-N5OOH can be a common reactive species in the superfamily of flavoenzymes, which accomplish generally selective general base catalysis and C-X (X=N, S, Cl, O) cleavage reactions that are otherwise challenging with solvated hydroxide ion base. These results expand our understanding of the chemistry and catalysis of flavoenzymes.
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Affiliation(s)
- Qiaoyu Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P. R. China
| | - Qianqian Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P. R. China
| | - Sason Shaik
- Institute of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904, Jerusalem, Israel
| | - Binju Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P. R. China
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6
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Austvold CK, Keable SM, Procopio M, Usselman RJ. Quantitative measurements of reactive oxygen species partitioning in electron transfer flavoenzyme magnetic field sensing. Front Physiol 2024; 15:1348395. [PMID: 38370016 PMCID: PMC10869518 DOI: 10.3389/fphys.2024.1348395] [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: 12/02/2023] [Accepted: 01/16/2024] [Indexed: 02/20/2024] Open
Abstract
Biological magnetic field sensing that gives rise to physiological responses is of considerable importance in quantum biology. The radical pair mechanism (RPM) is a fundamental quantum process that can explain some of the observed biological magnetic effects. In magnetically sensitive radical pair (RP) reactions, coherent spin dynamics between singlet and triplet pairs are modulated by weak magnetic fields. The resulting singlet and triplet reaction products lead to distinct biological signaling channels and cellular outcomes. A prevalent RP in biology is between flavin semiquinone and superoxide (O2 •-) in the biological activation of molecular oxygen. This RP can result in a partitioning of reactive oxygen species (ROS) products to form either O2 •- or hydrogen peroxide (H2O2). Here, we examine magnetic sensing of recombinant human electron transfer flavoenzyme (ETF) reoxidation by selectively measuring O2 •- and H2O2 product distributions. ROS partitioning was observed between two static magnetic fields at 20 nT and 50 μT, with a 13% decrease in H2O2 singlet products and a 10% increase in O2 •- triplet products relative to 50 µT. RPM product yields were calculated for a realistic flavin/superoxide RP across the range of static magnetic fields, in agreement with experimental results. For a triplet born RP, the RPM also predicts about three times more O2 •- than H2O2, with experimental results exhibiting about four time more O2 •- produced by ETF. The method presented here illustrates the potential of a novel magnetic flavoprotein biological sensor that is directly linked to mitochondria bioenergetics and can be used as a target to study cell physiology.
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Affiliation(s)
- Chase K. Austvold
- Chemistry and Biochemistry, Montana State University, Bozeman, MT, United States
| | - Stephen M. Keable
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Maria Procopio
- Biophysics, Johns Hopkins University, Baltimore, MD, United States
| | - Robert J. Usselman
- Chemistry and Chemical Engineering, Florida Institute of Technology, Melbourne, FL, United States
- Computational Research At Florida Tech, Melbourne, FL, United States
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7
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Heredia AA, Argüello JE, Schmidt LC. Metal- and base-free, aerobic photoredox catalysis with riboflavin to synthesize 2-substituted benzothiazoles. Org Biomol Chem 2024; 22:1064-1072. [PMID: 38205732 DOI: 10.1039/d3ob01851b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
Sustainable approaches for the synthesis of 2-substituted benzothiazoles are sought after for their use in organic chemistry, bioorganic chemistry, and industrial applications. Here, we described a visible light-driven photoredox catalytic cyclization of thioanilides to afford 2-substituted benzothiazoles using riboflavin as a photocatalyst, where oxygen is used as a clean oxidant and ethanol as a greener solvent. These results provide a new photochemical route for environmentally benign synthesis.
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Affiliation(s)
- Adrián A Heredia
- INFIQC-CONICET-UNC, Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA Córdoba, Argentina.
| | - Juan E Argüello
- INFIQC-CONICET-UNC, Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA Córdoba, Argentina.
| | - Luciana C Schmidt
- INFIQC-CONICET-UNC, Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA Córdoba, Argentina.
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avda. de los Naranjos s/n, E-46022, Valencia, Spain
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8
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Phintha A, Chaiyen P. Unifying and versatile features of flavin-dependent monooxygenases: Diverse catalysis by a common C4a-(hydro)peroxyflavin. J Biol Chem 2023; 299:105413. [PMID: 37918809 PMCID: PMC10696468 DOI: 10.1016/j.jbc.2023.105413] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 10/18/2023] [Accepted: 10/22/2023] [Indexed: 11/04/2023] Open
Abstract
Flavin-dependent monooxygenases (FDMOs) are known for their remarkable versatility and for their crucial roles in various biological processes and applications. Extensive research has been conducted to explore the structural and functional relationships of FDMOs. The majority of reported FDMOs utilize C4a-(hydro)peroxyflavin as a reactive intermediate to incorporate an oxygen atom into a wide range of compounds. This review discusses and analyzes recent advancements in our understanding of the structural and mechanistic features governing the enzyme functions. State-of-the-art discoveries related to common and distinct structural properties governing the catalytic versatility of the C4a-(hydro)peroxyflavin intermediate in selected FDMOs are discussed. Specifically, mechanisms of hydroxylation, dehalogenation, halogenation, and light-emitting reactions by FDMOs are highlighted. We also provide new analysis based on the structural and mechanistic features of these enzymes to gain insights into how the same intermediate can be harnessed to perform a wide variety of reactions. Challenging questions to obtain further breakthroughs in the understanding of FDMOs are also proposed.
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Affiliation(s)
- Aisaraphon Phintha
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Rayong, Thailand
| | - Pimchai Chaiyen
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Rayong, Thailand.
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9
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Dulchavsky M, Mitra R, Wu K, Li J, Boer K, Liu X, Zhang Z, Vasquez C, Clark CT, Funckes K, Shankar K, Bonnet-Zahedi S, Siddiq M, Sepulveda Y, Suhandynata RT, Momper JD, Calabrese AN, George O, Stull F, Bardwell JCA. Directed evolution unlocks oxygen reactivity for a nicotine-degrading flavoenzyme. Nat Chem Biol 2023; 19:1406-1414. [PMID: 37770699 PMCID: PMC10611581 DOI: 10.1038/s41589-023-01426-y] [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: 01/06/2023] [Accepted: 08/23/2023] [Indexed: 09/30/2023]
Abstract
The flavoenzyme nicotine oxidoreductase (NicA2) is a promising injectable treatment to aid in the cessation of smoking, a behavior responsible for one in ten deaths worldwide. NicA2 acts by degrading nicotine in the bloodstream before it reaches the brain. Clinical use of NicA2 is limited by its poor catalytic activity in the absence of its natural electron acceptor CycN. Without CycN, NicA2 is instead oxidized slowly by dioxygen (O2), necessitating unfeasibly large doses in a therapeutic setting. Here, we report a genetic selection strategy that directly links CycN-independent activity of NicA2 to growth of Pseudomonas putida S16. This selection enabled us to evolve NicA2 variants with substantial improvement in their rate of oxidation by O2. The encoded mutations cluster around a putative O2 tunnel, increasing flexibility and accessibility to O2 in this region. These mutations further confer desirable clinical properties. A variant form of NicA2 is tenfold more effective than the wild type at degrading nicotine in the bloodstream of rats.
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Affiliation(s)
- Mark Dulchavsky
- Howard Hughes Medical Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, USA
| | - Rishav Mitra
- Howard Hughes Medical Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Kevin Wu
- Howard Hughes Medical Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Joshua Li
- Howard Hughes Medical Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Karli Boer
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, USA
| | - Xiaomeng Liu
- Howard Hughes Medical Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Zhiyao Zhang
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, USA
| | - Cristian Vasquez
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, USA
| | | | - Kaitrin Funckes
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, USA
| | - Kokila Shankar
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
| | - Selene Bonnet-Zahedi
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
| | - Mohammad Siddiq
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Yadira Sepulveda
- School of Pharmacy and Pharmaceutical Science, University of California, San Diego, La Jolla, CA, USA
| | - Raymond T Suhandynata
- School of Pharmacy and Pharmaceutical Science, University of California, San Diego, La Jolla, CA, USA
- Department of Pathology, University of California, San Diego, La Jolla, CA, USA
| | - Jeremiah D Momper
- School of Pharmacy and Pharmaceutical Science, University of California, San Diego, La Jolla, CA, USA
| | - Antonio N Calabrese
- Astbury Centre for Structural Molecular Biology, S chool of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Olivier George
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
| | - Frederick Stull
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, USA
| | - James C A Bardwell
- Howard Hughes Medical Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
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10
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Minerdi D, Loqui D, Sabbatini P. Monooxygenases and Antibiotic Resistance: A Focus on Carbapenems. BIOLOGY 2023; 12:1316. [PMID: 37887026 PMCID: PMC10604202 DOI: 10.3390/biology12101316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 09/08/2023] [Accepted: 09/15/2023] [Indexed: 10/28/2023]
Abstract
Carbapenems are a group of broad-spectrum beta-lactam antibiotics that in many cases are the last effective defense against infections caused by multidrug-resistant bacteria, such as some strains of Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii. Resistance to carbapenems has emerged and is beginning to spread, becoming an ongoing public-health problem of global dimensions, causing serious outbreaks, and dramatically limiting treatment options. This paper reviews the role of flavin monooxygenases in antibiotic resistance, with a specific focus on carbapenem resistance and the recently discovered mechanism mediated by Baeyer-Villiger monooxygenases. Flavin monooxygenases are enzymes involved in the metabolism and detoxification of compounds, including antibiotics. Understanding their role in antibiotic resistance is crucial. Carbapenems are powerful antibiotics used to treat severe infections caused by multidrug-resistant bacteria. However, the rise of carbapenem-resistant strains poses a significant challenge. This paper explores the mechanisms by which flavin monooxygenases confer resistance to carbapenems, examining molecular pathways and genetic factors. Additionally, this paper highlights the discovery of Baeyer-Villiger monooxygenases' involvement in antibiotic resistance. These enzymes catalyze the insertion of oxygen atoms into specific chemical bonds. Recent studies have revealed their unexpected role in promoting carbapenem resistance. Through a comprehensive analysis of the literature, this paper contributes to the understanding of the interplay between flavin monooxygenases, carbapenem resistance, and Baeyer-Villiger monooxygenases. By exploring these mechanisms, it aims to inform the development of strategies to combat antibiotic resistance, a critical global health concern.
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Affiliation(s)
- Daniela Minerdi
- Department of Agricultural, Forestry and Food Sciences, University of Turin, Largo Paolo Braccini 2, 10095 Grugliasco, TO, Italy;
| | - Davide Loqui
- Emergency Department, Città della Salute e della Scienza of Turin, 10100 Turin, TO, Italy;
| | - Paolo Sabbatini
- Department of Agricultural, Forestry and Food Sciences, University of Turin, Largo Paolo Braccini 2, 10095 Grugliasco, TO, Italy;
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11
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Wang Q, Liu N, Deng Y, Guan Y, Xiao H, Nitka TA, Yang H, Yadav A, Vukovic L, Mathews II, Chen X, Kim CY. Triepoxide formation by a flavin-dependent monooxygenase in monensin biosynthesis. Nat Commun 2023; 14:6273. [PMID: 37805629 PMCID: PMC10560226 DOI: 10.1038/s41467-023-41889-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 09/18/2023] [Indexed: 10/09/2023] Open
Abstract
Monensin A is a prototypical natural polyether polyketide antibiotic. It acts by binding a metal cation and facilitating its transport across the cell membrane. Biosynthesis of monensin A involves construction of a polyene polyketide backbone, subsequent epoxidation of the alkenes, and, lastly, formation of cyclic ethers via epoxide-opening cyclization. MonCI, a flavin-dependent monooxygenase, is thought to transform all three alkenes in the intermediate polyketide premonensin A into epoxides. Our crystallographic study has revealed that MonCI's exquisite stereocontrol is due to the preorganization of the active site residues which allows only one specific face of the alkene to approach the reactive C(4a)-hydroperoxyflavin moiety. Furthermore, MonCI has an unusually large substrate-binding cavity that can accommodate premonensin A in an extended or folded conformation which allows any of the three alkenes to be placed next to C(4a)-hydroperoxyflavin. MonCI, with its ability to perform multiple epoxidations on the same substrate in a stereospecific manner, demonstrates the extraordinary versatility of the flavin-dependent monooxygenase family of enzymes.
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Affiliation(s)
- Qian Wang
- Department of Chemistry and Biochemistry, The University of Texas at El Paso, 500 West University Avenue, El Paso, TX, 79968, USA
| | - Ning Liu
- Key Laboratory of Synthetic and Natural Functional Molecular Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, 710127, Xi'an, China
| | - Yaming Deng
- Key Laboratory of Synthetic and Natural Functional Molecular Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, 710127, Xi'an, China
| | - Yuze Guan
- Key Laboratory of Synthetic and Natural Functional Molecular Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, 710127, Xi'an, China
| | - Hongli Xiao
- Key Laboratory of Synthetic and Natural Functional Molecular Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, 710127, Xi'an, China
| | - Tara A Nitka
- Department of Chemistry and Biochemistry, The University of Texas at El Paso, 500 West University Avenue, El Paso, TX, 79968, USA
| | - Hui Yang
- Key Laboratory of Synthetic and Natural Functional Molecular Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, 710127, Xi'an, China
| | - Anju Yadav
- Department of Chemistry and Biochemistry, The University of Texas at El Paso, 500 West University Avenue, El Paso, TX, 79968, USA
| | - Lela Vukovic
- Department of Chemistry and Biochemistry, The University of Texas at El Paso, 500 West University Avenue, El Paso, TX, 79968, USA
| | - Irimpan I Mathews
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 95124, USA
| | - Xi Chen
- Key Laboratory of Synthetic and Natural Functional Molecular Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, 710127, Xi'an, China.
| | - Chu-Young Kim
- Department of Chemistry and Biochemistry, The University of Texas at El Paso, 500 West University Avenue, El Paso, TX, 79968, USA.
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA.
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12
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Dai Y, Xie XL, Dai HF, Li SM. Formation of Fungal 2,18-Dioxo-2,18- seco Indole Diterpenes by Nonenzymatic Flavin-Catalyzed Oxidative Ring Expansion and Oxygen Incorporation from Solvent Water. Org Lett 2023; 25:4092-4097. [PMID: 37249271 DOI: 10.1021/acs.orglett.3c01320] [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: 05/31/2023]
Abstract
Most naturally occurring indole diterpenes share a 6/5/5/6/6/6 hexacyclic ring system, while a 6/8/6/6/6 pentacyclic skeleton is occasionally observed. In this study, we demonstrate the formation of an eight-membered C-N heteroring via nonenzymatic flavin-catalyzed oxidative indole ring opening. More interestingly, 18O-labeled experiments proved that the two incorporated oxygen atoms are predominantly originated from water instead of molecular oxygen. In this process, the oxidized form of flavin catalyzes two successive oxidations of amines to imines with involvement of hydrolysis for the ring expansion. The reduced flavin is then regenerated by oxidation with molecular oxygen to form H2O2.
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Affiliation(s)
- Yu Dai
- Institut für Pharmazeutische Biologie und Biotechnologie, Fachbereich Pharmazie, Philipps-Universität Marburg, Robert-Koch-Straße 4, 35037 Marburg, Germany
| | - Xiu-Lan Xie
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany
| | - Hao-Fu Dai
- Research and Development of Natural Products from Li Folk Medicine, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agriculture Sciences, Haikou 571101, China
| | - Shu-Ming Li
- Institut für Pharmazeutische Biologie und Biotechnologie, Fachbereich Pharmazie, Philipps-Universität Marburg, Robert-Koch-Straße 4, 35037 Marburg, Germany
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13
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Jiang S, Chen X, Lin J, Huang P. Lactate-Oxidase-Instructed Cancer Diagnosis and Therapy. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2207951. [PMID: 36353879 DOI: 10.1002/adma.202207951] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/15/2022] [Indexed: 05/12/2023]
Abstract
Lactate oxidase (LOx) has attracted extensive interest in cancer diagnosis and therapy in recent years owing to its specific catalysis on l-lactate; its catalytic process consumes oxygen (O2 ) and generates a large amount of hydrogen peroxide (H2 O2 ) and pyruvate. Given high levels of lactate in tumor tissues and its tight correlation with tumor growth, metastasis, and recurrence, LOx-based biosensors including H2 O2 -based, O2 -based, pH-sensitive, and electrochemical have been designed for cancer diagnosis, and various LOx-based cancer therapy strategies including lactate-depletion-based metabolic cancer therapy/immunotherapy, hypoxia-activated chemotherapy, H2 O2 -based chemodynamic therapy, and multimodal synergistic cancer therapy have also been developed. In this review, the lactate-specific catalytic properties of LOx are introduced, and the recent advances on LOx-instructed cancer diagnostic or therapeutic platforms and corresponding biological applications are summarized. Additionally, the challenges and potential of LOx-based nanomedicines are highlighted.
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Affiliation(s)
- Shanshan Jiang
- Marshall Laboratory of Biomedical Engineering, International Cancer Center, Laboratory of Evolutionary Theranostics (LET), School of Biomedical Engineering, Shenzhen University Health Science Center, Shenzhen, 518060, China
| | - Xin Chen
- Marshall Laboratory of Biomedical Engineering, International Cancer Center, Laboratory of Evolutionary Theranostics (LET), School of Biomedical Engineering, Shenzhen University Health Science Center, Shenzhen, 518060, China
| | - Jing Lin
- Marshall Laboratory of Biomedical Engineering, International Cancer Center, Laboratory of Evolutionary Theranostics (LET), School of Biomedical Engineering, Shenzhen University Health Science Center, Shenzhen, 518060, China
| | - Peng Huang
- Marshall Laboratory of Biomedical Engineering, International Cancer Center, Laboratory of Evolutionary Theranostics (LET), School of Biomedical Engineering, Shenzhen University Health Science Center, Shenzhen, 518060, China
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14
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Ortega P, Gil-Guerrero S, González-Sánchez L, Sanz-Sanz C, Jambrina PG. Spin-Forbidden Addition of Molecular Oxygen to Stable Enol Intermediates-Decarboxylation of 2-Methyl-1-tetralone-2-carboxylic Acid. Int J Mol Sci 2023; 24:ijms24087424. [PMID: 37108586 PMCID: PMC10138960 DOI: 10.3390/ijms24087424] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 04/12/2023] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
The deprotonation of an organic substrate is a common preactivation step for the enzymatic cofactorless addition of O2 to this substrate, as it promotes charge-transfer between the two partners, inducing intersystem crossing between the triplet and singlet states involved in the process. Nevertheless, the spin-forbidden addition of O2 to uncharged ligands has also been observed in the laboratory, and the detailed mechanism of how the system circumvents the spin-forbiddenness of the reaction is still unknown. One of these examples is the cofactorless peroxidation of 2-methyl-3,4-dihydro-1-naphthol, which will be studied computationally using single and multi-reference electronic structure calculations. Our results show that the preferred mechanism is that in which O2 picks a proton from the substrate in the triplet state, and subsequently hops to the singlet state in which the product is stable. For this reaction, the formation of the radical pair is associated with a higher barrier than that associated with the intersystem crossing, even though the absence of the negative charge leads to relatively small values of the spin-orbit coupling.
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Affiliation(s)
- Pablo Ortega
- Departamento de Química-Física, Universidad de Salamanca, 37008 Salamanca, Spain
| | - Sara Gil-Guerrero
- Departamento de Química-Física, Universidad de Salamanca, 37008 Salamanca, Spain
- CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal
| | | | - Cristina Sanz-Sanz
- Departamento de Química Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Pablo G Jambrina
- Departamento de Química-Física, Universidad de Salamanca, 37008 Salamanca, Spain
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15
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Wang Y, Song L, Ning M, Hu J, Cai H, Song W, Gong D, Liu L, Smith J, Li H, Huang Y. Identification of alternative splicing events related to fatty liver formation in duck using full-length transcripts. BMC Genomics 2023; 24:92. [PMID: 36858953 PMCID: PMC9976415 DOI: 10.1186/s12864-023-09160-4] [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: 11/21/2022] [Accepted: 01/31/2023] [Indexed: 03/03/2023] Open
Abstract
BACKGROUND Non-alcoholic fatty liver disease (NAFLD) is one of most common diseases in the world. Recently, alternative splicing (AS) has been reported to play a key role in NAFLD processes in mammals. Ducks can quickly form fatty liver similar to human NAFLD after overfeeding and restore to normal liver in a short time, suggesting that ducks are an excellent model to unravel molecular mechanisms of lipid metabolism for NAFLD. However, how alternative splicing events (ASEs) affect the fatty liver process in ducks is still unclear. RESULTS Here we identify 126,277 unique transcripts in liver tissue from an overfed duck (77,237 total transcripts) and its sibling control (69,618 total transcripts). We combined these full-length transcripts with Illumina RNA-seq data from five pairs of overfed ducks and control individuals. Full-length transcript sequencing provided us with structural information of transcripts and Illumina RNA-seq data reveals the expressional profile of each transcript. We found, among these unique transcripts, 30,618 were lncRNAs and 1,744 transcripts including 155 lncRNAs and 1,589 coding transcripts showed significantly differential expression in liver tissues between overfed ducks and control individuals. We also detected 27,317 ASEs and 142 of them showed significant relative abundance changes in ducks under different feeding conditions. Full-length transcript profiles together with Illumina RNA-seq data demonstrated that 10 genes involving in lipid metabolism had ASEs with significantly differential abundance in normally fed (control) and overfed ducks. Among these genes, protein products of five genes (CYP4F22, BTN, GSTA2, ADH5, and DHRS2 genes) were changed by ASEs. CONCLUSIONS This study presents an example of how to identify ASEs related to important biological processes, such as fatty liver formation, using full-length transcripts alongside Illumina RNA-seq data. Based on these data, we screened out ASEs of lipid-metabolism related genes which might respond to overfeeding. Our future ability to explore the function of genes showing AS differences between overfed ducks and their sibling controls, using genetic manipulations and co-evolutionary studies, will certainly extend our knowledge of genes related to the non-pathogenic fatty liver process.
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Affiliation(s)
- Yiming Wang
- State Key Laboratory for Agrobiotechnology, College of Biology Sciences, China Agricultural University, No.2 Yuan Ming Yuan West Road, Hai Dian District, Beijing, 100193, China
| | - Linfei Song
- State Key Laboratory for Agrobiotechnology, College of Biology Sciences, China Agricultural University, No.2 Yuan Ming Yuan West Road, Hai Dian District, Beijing, 100193, China
| | - Mengfei Ning
- State Key Laboratory for Agrobiotechnology, College of Biology Sciences, China Agricultural University, No.2 Yuan Ming Yuan West Road, Hai Dian District, Beijing, 100193, China
| | - Jiaxiang Hu
- State Key Laboratory for Agrobiotechnology, College of Biology Sciences, China Agricultural University, No.2 Yuan Ming Yuan West Road, Hai Dian District, Beijing, 100193, China
| | - Han Cai
- State Key Laboratory for Agrobiotechnology, College of Biology Sciences, China Agricultural University, No.2 Yuan Ming Yuan West Road, Hai Dian District, Beijing, 100193, China
| | - Weitao Song
- Department of Waterfowl Breeding and Production, Jiangsu Institute of Poultry Science, No. 58 Cangjie Road, Hanjiang District, Yangzhou, 349019093, China
| | - Daoqing Gong
- College of Animal Science and Technology, Yangzhou University, Yangzhou, China
| | - Long Liu
- College of Animal Science and Technology, Yangzhou University, Yangzhou, China
| | - Jacqueline Smith
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, UK
| | - Huifang Li
- Department of Waterfowl Breeding and Production, Jiangsu Institute of Poultry Science, No. 58 Cangjie Road, Hanjiang District, Yangzhou, 349019093, China.
| | - Yinhua Huang
- State Key Laboratory for Agrobiotechnology, College of Biology Sciences, China Agricultural University, No.2 Yuan Ming Yuan West Road, Hai Dian District, Beijing, 100193, China.
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16
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Polyakov IV, Nemukhin AV, Domratcheva TM, Kulakova AM, Grigorenko BL. Quantum-based Modeling of Protein-ligand Interaction: The Complex of RutA with Uracil and Molecular Oxygen. Mol Inform 2023; 42:e2200175. [PMID: 36259359 DOI: 10.1002/minf.202200175] [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: 07/25/2022] [Accepted: 10/18/2022] [Indexed: 11/09/2022]
Abstract
Modern quantum-based methods are employed to model interaction of the flavin-dependent enzyme RutA with the uracil and oxygen molecules. This complex presents the structure of reactants for the chain of chemical reactions of monooxygenation in the enzyme active site, which is important in drug metabolism. In this case, application of quantum-based approaches is an essential issue, unlike conventional modeling of protein-ligand interaction with force fields using molecular mechanics and classical molecular dynamics methods. We focus on two difficult problems to characterize the structure of reactants in the RutA-FMN-O2 -uracil complex, where FMN stands for the flavin mononucleotide species. First, location of a small O2 molecule in the triplet spin state in the protein cavities is required. Second, positions of both ligands, O2 and uracil, must be specified in the active site with a comparable accuracy. We show that the methods of molecular dynamics with the interaction potentials of quantum mechanics/molecular mechanics theory (QM/MM MD) allow us to characterize this complex and, in addition, to surmise possible reaction mechanism of uracil oxygenation by RutA.
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Affiliation(s)
- Igor V Polyakov
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russia.,Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, 119334, Russia
| | - Alexander V Nemukhin
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russia.,Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, 119334, Russia
| | | | - Anna M Kulakova
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Bella L Grigorenko
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russia.,Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, 119334, Russia
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17
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Zhang L, Toplak M, Saleem-Batcha R, Höing L, Jakob R, Jehmlich N, von Bergen M, Maier T, Teufel R. Bacterial Dehydrogenases Facilitate Oxidative Inactivation and Bioremediation of Chloramphenicol. Chembiochem 2023; 24:e202200632. [PMID: 36353978 DOI: 10.1002/cbic.202200632] [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: 11/02/2022] [Revised: 11/09/2022] [Indexed: 11/11/2022]
Abstract
Antimicrobial resistance represents a major threat to human health and knowledge of the underlying mechanisms is therefore vital. Here, we report the discovery and characterization of oxidoreductases that inactivate the broad-spectrum antibiotic chloramphenicol via dual oxidation of the C3-hydroxyl group. Accordingly, chloramphenicol oxidation either depends on standalone glucose-methanol-choline (GMC)-type flavoenzymes, or on additional aldehyde dehydrogenases that boost overall turnover. These enzymes also enable the inactivation of the chloramphenicol analogues thiamphenicol and azidamfenicol, but not of the C3-fluorinated florfenicol. Notably, distinct isofunctional enzymes can be found in Gram-positive (e. g., Streptomyces sp.) and Gram-negative (e. g., Sphingobium sp.) bacteria, which presumably evolved their selectivity for chloramphenicol independently based on phylogenetic analyses. Mechanistic and structural studies provide further insights into the catalytic mechanisms of these biotechnologically interesting enzymes, which, in sum, are both a curse and a blessing by contributing to the spread of antibiotic resistance as well as to the bioremediation of chloramphenicol.
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Affiliation(s)
- Lei Zhang
- Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104, Freiburg, Germany
| | - Marina Toplak
- Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104, Freiburg, Germany
| | - Raspudin Saleem-Batcha
- Institute of Pharmaceutical Sciences, University of Freiburg, Albertstrasse 25, 79104, Freiburg, Germany
| | - Lars Höing
- Pharmaceutical Biology, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
| | - Roman Jakob
- Biozentrum, University of Basel, Spitalstrasse 41, 4056, Basel, Switzerland
| | - Nico Jehmlich
- Department of Molecular Systems Biology, Helmholtz-Centre for Environmental Research UFZ GmbH, Leipzig, Germany.,German Centre for Integrative Biodiversity Research, (iDiv) Halle-Jena-Leipzig, Puschstraße 4, 04103, Leipzig, Germany.,University of Leipzig, Faculty of Life Sciences, Institute of Biochemistry, Brüderstraße 34, 04103, Leipzig, Germany
| | - Martin von Bergen
- Department of Molecular Systems Biology, Helmholtz-Centre for Environmental Research UFZ GmbH, Leipzig, Germany.,German Centre for Integrative Biodiversity Research, (iDiv) Halle-Jena-Leipzig, Puschstraße 4, 04103, Leipzig, Germany.,University of Leipzig, Faculty of Life Sciences, Institute of Biochemistry, Brüderstraße 34, 04103, Leipzig, Germany
| | - Timm Maier
- Biozentrum, University of Basel, Spitalstrasse 41, 4056, Basel, Switzerland
| | - Robin Teufel
- Pharmaceutical Biology, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
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18
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Uppu RM, Fronczek FR. 1 H-Benzo[ g]pteridine-2,4-dione. IUCRDATA 2023; 8:x221223. [PMID: 36794048 PMCID: PMC9912317 DOI: 10.1107/s2414314622012238] [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: 12/28/2022] [Accepted: 12/29/2022] [Indexed: 01/09/2023] Open
Abstract
The structure of the title compound, C10H6N4O2, reported by Smalley et al. [(2021). Cryst. Growth Des. 22, 524-534] from powder diffraction data and 15N NMR spectroscopy, is confirmed using low-temperature data from a twinned crystal. The tautomer in the solid state is alloxazine (1H-benzo[g]pteridine-2,4-dione) rather than isoalloxazine (10H-benzo[g]pteridine-2,4-dione). In the extended structure, the mol-ecules form hydrogen-bonded chains propagating in the [01] direction through alternating centrosymmetric R 2 2(8) rings with pairwise N-H⋯O inter-actions and centrosymmetric R 2 2(8) rings with pairwise N-H⋯N inter-actions. The crystal chosen for data collection was found to be a non-merohedral twin (180° rotation about [001]) in a 0.446 (4):0.554 (6) domain ratio.
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Affiliation(s)
- Rao M. Uppu
- Department of Environmental Toxicology, Southern University and A&M College, Baton Rouge, LA 70813, USA,Correspondence e-mail:
| | - Frank R. Fronczek
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA
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19
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Pimviriyakul P, Chaiyen P. Formation and stabilization of C4a-hydroperoxy-FAD by the Arg/Asn pair in HadA monooxygenase. FEBS J 2023; 290:176-195. [PMID: 35942637 DOI: 10.1111/febs.16591] [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: 06/15/2022] [Revised: 07/25/2022] [Accepted: 08/08/2022] [Indexed: 01/14/2023]
Abstract
HadA monooxygenase catalyses the detoxification of halogenated phenols and nitrophenols via dehalogenation and denitration respectively. C4a-hydroperoxy-FAD is a key reactive intermediate wherein its formation, protonation and stabilization reflect enzyme efficiency. Herein, transient kinetics, site-directed mutagenesis and pH-dependent behaviours of HadA reaction were employed to identify key features stabilizing C4a-adducts in HadA. The formation of C4a-hydroperoxy-FAD is pH independent, whereas its decay and protonation of distal oxygen are associated with pKa values of 8.5 and 8.4 respectively. These values are correlated with product formation within a pH range of 7.6-9.1, indicating the importance of adduct stabilization to enzymatic efficiency. We identified Arg101 as a key residue for reduced FAD (FADH- ) binding and C4a-hydroperoxy-FAD formation due to the loss of these abilities as well as enzyme activity in HadAR101A and HadAR101Q . Mutations of the neighbouring Asn447 do not affect the rate of C4a-hydroperoxy-FAD formation; however, they impair FADH- binding. The disruption of Arg101/Asn447 hydrogen bond networking in HadAN447A increases the pKa value of C4a-hydroperoxy-FAD decay to 9.5; however, this pKa was not altered in HadAN447D (pKa of 8.5). Thus, Arg101/Asn447 pair should provide important interactions for FADH- binding and maintain the pKa associated with H2 O2 elimination from C4a-hydroperoxy-FAD in HadA. In the presence of substrate, the formation of C4a-hydroxy-FAD at the hydroxylation step is pH insensitive, and it dehydrates to form the oxidized FAD with pKa of 7.9. This structural feature might help elucidate how the reactive intermediate was stabilized in other flavin-dependent monooxygenases.
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Affiliation(s)
- Panu Pimviriyakul
- Department of Biochemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Pimchai Chaiyen
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
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20
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Lyons NS, Bogner AN, Tanner JJ, Sobrado P. Kinetic and Structural Characterization of a Flavin-Dependent Putrescine N-Hydroxylase from Acinetobacter baumannii. Biochemistry 2022; 61:2607-2620. [DOI: 10.1021/acs.biochem.2c00493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Noah S. Lyons
- Department of Biochemistry and Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Alexandra N. Bogner
- Department of Biochemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - John J. Tanner
- Department of Biochemistry, University of Missouri, Columbia, Missouri 65211, United States
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Pablo Sobrado
- Department of Biochemistry and Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia 24061, United States
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21
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Ernst S, Mährlein A, Ritzmann NH, Drees SL, Fetzner S. A comparative study of
N
‐hydroxylating flavoprotein monooxygenases reveals differences in kinetics and cofactor binding. FEBS J 2022; 289:5637-5655. [DOI: 10.1111/febs.16444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 02/21/2022] [Accepted: 03/18/2022] [Indexed: 12/01/2022]
Affiliation(s)
- Simon Ernst
- Institute of Molecular Microbiology and Biotechnology University of Münster Germany
| | - Almuth Mährlein
- Institute of Molecular Microbiology and Biotechnology University of Münster Germany
| | - Niklas H. Ritzmann
- Institute of Molecular Microbiology and Biotechnology University of Münster Germany
| | - Steffen L. Drees
- Institute of Molecular Microbiology and Biotechnology University of Münster Germany
| | - Susanne Fetzner
- Institute of Molecular Microbiology and Biotechnology University of Münster Germany
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22
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Partipilo M, Yang G, Mascotti ML, Wijma HJ, Slotboom DJ, Fraaije MW. A conserved sequence motif in the E. coli soluble FAD-containing pyridine nucleotide transhydrogenase is important for reaction efficiency. J Biol Chem 2022; 298:102304. [PMID: 35933012 PMCID: PMC9460512 DOI: 10.1016/j.jbc.2022.102304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 07/20/2022] [Accepted: 07/21/2022] [Indexed: 11/06/2022] Open
Abstract
Soluble pyridine nucleotide transhydrogenases (STHs) are flavoenzymes involved in the redox homeostasis of the essential cofactors NAD(H) and NADP(H). They catalyze the reversible transfer of reducing equivalents between the two nicotinamide cofactors. The soluble transhydrogenase from Escherichia coli (SthA) has found wide use in both in vivo and in vitro applications to steer reducing equivalents toward NADPH-requiring reactions. However, mechanistic insight into SthA function is still lacking. In this work, we present a biochemical characterization of SthA, focusing for the first time on the reactivity of the flavoenzyme with molecular oxygen. We report on oxidase activity of SthA that takes place both during transhydrogenation and in the absence of an oxidized nicotinamide cofactor as an electron acceptor. We find that this reaction produces the reactive oxygen species hydrogen peroxide and superoxide anion. Furthermore, we explore the evolutionary significance of the well-conserved CXXXXT motif that distinguishes STHs from the related family of flavoprotein disulfide reductases in which a CXXXXC motif is conserved. Our mutational analysis revealed the cysteine and threonine combination in SthA leads to better coupling efficiency of transhydrogenation and reduced reactive oxygen species release compared to enzyme variants with mutated motifs. These results expand our mechanistic understanding of SthA by highlighting reactivity with molecular oxygen and the importance of the evolutionarily conserved sequence motif.
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Affiliation(s)
- Michele Partipilo
- Membrane Enzymology Group, Groningen Institute of Biomolecular Sciences & Biotechnology, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Guang Yang
- Molecular Enzymology Group, Groningen Institute of Biomolecular Sciences & Biotechnology, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Maria Laura Mascotti
- Molecular Enzymology Group, Groningen Institute of Biomolecular Sciences & Biotechnology, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands; IMIBIO-SL CONICET, Facultad de Química Bioquímica y Farmacia, Universidad Nacional de San Luis, Ejercito de los Andes 950, D5700HHW, San Luis, Argentina
| | - Hein J Wijma
- Molecular Enzymology Group, Groningen Institute of Biomolecular Sciences & Biotechnology, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Dirk Jan Slotboom
- Membrane Enzymology Group, Groningen Institute of Biomolecular Sciences & Biotechnology, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
| | - Marco W Fraaije
- Molecular Enzymology Group, Groningen Institute of Biomolecular Sciences & Biotechnology, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
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23
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Choudhary V, Wu K, Zhang Z, Dulchavsky M, Barkman T, Bardwell JCA, Stull F. The enzyme pseudooxynicotine amine oxidase from Pseudomonas putida S16 is not an oxidase, but a dehydrogenase. J Biol Chem 2022; 298:102251. [PMID: 35835223 PMCID: PMC9396064 DOI: 10.1016/j.jbc.2022.102251] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 07/07/2022] [Accepted: 07/08/2022] [Indexed: 11/16/2022] Open
Abstract
The soil-dwelling bacterium Pseudomonas putida S16 can survive on nicotine as its sole carbon and nitrogen source. The enzymes nicotine oxidoreductase (NicA2) and pseudooxynicotine amine oxidase (Pnao), both members of the flavin containing amine oxidase family, catalyze the first two steps in the nicotine catabolism pathway. Our laboratory has previously shown that, contrary to other members of its enzyme family, NicA2 is actually a dehydrogenase that uses a cytochrome c protein (CycN) as its electron acceptor. The natural electron acceptor for Pnao is unknown; however, within the P. putida S16 genome, pnao forms an operon with cycN and nicA2, leading us to hypothesize that Pnao may also be a dehydrogenase that uses CycN as its electron acceptor. Here we characterized the kinetic properties of Pnao and show that Pnao is poorly oxidized by O2, but can be rapidly oxidized by CycN, indicating that Pnao indeed acts as a dehydrogenase that uses CycN as its oxidant. Comparing steady-state kinetics with transient kinetic experiments revealed that product release primarily limits turnover by Pnao. We also resolved the crystal structure of Pnao at 2.60 Å, which shows that Pnao has a similar structural fold as NicA2. Furthermore, rigid-body docking of the structure of CycN with Pnao and NicA2 identified a potential conserved binding site for CycN on these two enzymes. Taken together, our results demonstrate that although Pnao and NicA2 show a high degree of similarity to flavin containing amine oxidases that use dioxygen directly, both enzymes are actually dehydrogenases.
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Affiliation(s)
- Vishakha Choudhary
- Department of Chemistry, Western Michigan University, Kalamazoo, Michigan, USA
| | - Kevin Wu
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, Michigan, USA; Department of Biophysics, University of Michigan, Ann Arbor, Michigan, USA
| | - Zhiyao Zhang
- Department of Chemistry, Western Michigan University, Kalamazoo, Michigan, USA
| | - Mark Dulchavsky
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, Michigan, USA; Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan, USA
| | - Todd Barkman
- Department of Biological Sciences, Western Michigan University, Kalamazoo, Michigan, USA
| | - James C A Bardwell
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, Michigan, USA; Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Frederick Stull
- Department of Chemistry, Western Michigan University, Kalamazoo, Michigan, USA.
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Pompe N, Illarionov B, Fischer M, Bacher A, Weber S. Completing the Picture: Determination of 13C Hyperfine Coupling Constants of Flavin Semiquinone Radicals by Photochemically Induced Dynamic Nuclear Polarization Spectroscopy. J Phys Chem Lett 2022; 13:5160-5167. [PMID: 35658481 DOI: 10.1021/acs.jpclett.2c00919] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
We investigate the electronic structure of flavin semiquinone radicals in terms of their 13C hyperfine coupling constants. Photochemically induced dynamic nuclear polarization (photo-CIDNP) spectroscopy was used to study both the neutral and anionic radical species of flavin mononucleotide (FMN) in bulk aqueous solution. Apart from universally 13C-labeled FMN, partially labeled isotopologues are used to increase sensitivity for nuclei exhibiting very small hyperfine couplings and to cope with spectral overlap. In addition, experimental findings are supported by quantum chemical calculations, and implications for the spin density distribution in free flavin radicals are discussed.
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Affiliation(s)
- Nils Pompe
- Institute of Physical Chemistry, University of Freiburg, 79104 Freiburg im Breisgau, Germany
| | - Boris Illarionov
- Hamburg School of Food Science, University of Hamburg, 20146 Hamburg, Germany
| | - Markus Fischer
- Hamburg School of Food Science, University of Hamburg, 20146 Hamburg, Germany
| | - Adelbert Bacher
- Department of Chemistry, Technical University of Munich, 85748 Garching, Germany
| | - Stefan Weber
- Institute of Physical Chemistry, University of Freiburg, 79104 Freiburg im Breisgau, Germany
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25
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Structural enzymology of cholesterol biosynthesis and storage. Curr Opin Struct Biol 2022; 74:102369. [DOI: 10.1016/j.sbi.2022.102369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 02/02/2022] [Accepted: 03/01/2022] [Indexed: 11/15/2022]
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26
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Gueskine V, Vagin M, Berggren M, Crispin X, Zozoulenko I. Oxygen reduction reaction at conducting polymer electrodes in a wider context: Insights from modelling concerning outer and inner sphere mechanisms. ELECTROCHEMICAL SCIENCE ADVANCES 2022. [DOI: 10.1002/elsa.202100191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Viktor Gueskine
- Laboratory of Organic Electronics Department of Science and Technology Linköping University Norrköping 601 74 Sweden
| | - Mikhail Vagin
- Laboratory of Organic Electronics Department of Science and Technology Linköping University Norrköping 601 74 Sweden
| | - Magnus Berggren
- Laboratory of Organic Electronics Department of Science and Technology Linköping University Norrköping 601 74 Sweden
| | - Xavier Crispin
- Laboratory of Organic Electronics Department of Science and Technology Linköping University Norrköping 601 74 Sweden
| | - Igor Zozoulenko
- Laboratory of Organic Electronics Department of Science and Technology Linköping University Norrköping 601 74 Sweden
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27
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Properties and Mechanisms of Flavin-Dependent Monooxygenases and Their Applications in Natural Product Synthesis. Int J Mol Sci 2022; 23:ijms23052622. [PMID: 35269764 PMCID: PMC8910399 DOI: 10.3390/ijms23052622] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/21/2022] [Accepted: 02/25/2022] [Indexed: 11/17/2022] Open
Abstract
Natural products are usually highly complicated organic molecules with special scaffolds, and they are an important resource in medicine. Natural products with complicated structures are produced by enzymes, and this is still a challenging research field, its mechanisms requiring detailed methods for elucidation. Flavin adenine dinucleotide (FAD)-dependent monooxygenases (FMOs) catalyze many oxidation reactions with chemo-, regio-, and stereo-selectivity, and they are involved in the synthesis of many natural products. In this review, we introduce the mechanisms for different FMOs, with the classical FAD (C4a)-hydroperoxide as the major oxidant. We also summarize the difference between FMOs and cytochrome P450 (CYP450) monooxygenases emphasizing the advantages of FMOs and their specificity for substrates. Finally, we present examples of FMO-catalyzed synthesis of natural products. Based on these explanations, this review will expand our knowledge of FMOs as powerful enzymes, as well as implementation of the FMOs as effective tools for biosynthesis.
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Lawan N, Tinikul R, Surawatanawong P, Mulholland AJ, Chaiyen P. QM/MM Molecular Modeling Reveals Mechanism Insights into Flavin Peroxide Formation in Bacterial Luciferase. J Chem Inf Model 2022; 62:399-411. [PMID: 34989561 DOI: 10.1021/acs.jcim.1c01187] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Bacterial luciferase (Lux) catalyzes oxidation of reduced flavin mononucleotide (FMN) and aldehyde to form oxidized FMN and carboxylic acid via molecular oxygen with concomitant light generation. The enzyme is useful for various detection applications in biomedical experiments. Upon reacting with oxygen, the reduced FMN generates C4a-peroxy-FMN (FMNH-C4a-OO-) as a reactive intermediate, which is required for light generation. However, the mechanism and control of FMNH-C4a-OO- formation are not clear. This work investigated the reaction of FMNH-C4a-OO- formation in Lux using QM/MM methods. The B3LYP/6-31G*/CHARMM27 calculations indicate that Lux controls the formation of FMNH-C4a-OO- via the conserved His44 residue. The steps in intermediate formation are found to be as follows: (i) H+ reacts with O2 to generate +OOH. (ii) +OOH attacks C4a of FMNH- to generate FMNH-C4a-OOH. (iii) H+ is transferred from FMNH-C4a-OOH to His44 to generate FMNH-C4a-OO- while His44 stabilizes FMNH-C4a-OO- by forming a hydrogen bond to an oxygen atom. This controlling key mechanism for driving the change from FMNH-C4a-OOH to the FMNH-C4a-OO- adduct is confirmed because FMNH-C4a-OO- is more stable than FMNH-C4a-OOH in the luciferase active site.
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Affiliation(s)
- Narin Lawan
- Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Ruchanok Tinikul
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Panida Surawatanawong
- Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Adrian J Mulholland
- Centre for Computational Chemistry, School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom
| | - Pimchai Chaiyen
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Rayong 21210, Thailand
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30
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Zadeh-Haghighi H, Simon C. Radical pairs can explain magnetic field and lithium effects on the circadian clock. Sci Rep 2022; 12:269. [PMID: 34997158 PMCID: PMC8742017 DOI: 10.1038/s41598-021-04334-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 12/14/2021] [Indexed: 12/21/2022] Open
Abstract
Drosophila's circadian clock can be perturbed by magnetic fields, as well as by lithium administration. Cryptochromes are critical for the circadian clock. Further, the radical pairs in cryptochrome also can explain magnetoreception in animals. Based on a simple radical pair mechanism model of the animal magnetic compass, we show that both magnetic fields and lithium can influence the spin dynamics of the naturally occurring radical pairs and hence modulate the circadian clock's rhythms. Using a simple chemical oscillator model for the circadian clock, we show that the spin dynamics influence a rate in the chemical oscillator model, which translates into a change in the circadian period. Our model can reproduce the results of two independent experiments, magnetic field and lithium effects on the circadian clock. Our model predicts that stronger magnetic fields would shorten the clock's period. We also predict that lithium influences the clock in an isotope-dependent manner. Furthermore, our model also predicts that magnetic fields and hyperfine interactions modulate oxidative stress. The findings of this work suggest that the quantum nature of radical pairs might play roles in the brain, as another piece of evidence in addition to recent results on xenon anesthesia and lithium effects on hyperactivity.
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Affiliation(s)
- Hadi Zadeh-Haghighi
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Institute for Quantum Science and Technology, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 1N4, Canada.
| | - Christoph Simon
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Institute for Quantum Science and Technology, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 1N4, Canada.
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31
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Toplak M, Saleem-Batcha R, Piel J, Teufel R. Catalytic Control of Spiroketal Formation in Rubromycin Polyketide Biosynthesis. Angew Chem Int Ed Engl 2021; 60:26960-26970. [PMID: 34652045 PMCID: PMC9299503 DOI: 10.1002/anie.202109384] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 10/07/2021] [Indexed: 12/14/2022]
Abstract
The medically important bacterial aromatic polyketide natural products typically feature a planar, polycyclic core structure. An exception is found for the rubromycins, whose backbones are disrupted by a bisbenzannulated [5,6]‐spiroketal pharmacophore that was recently shown to be assembled by flavin‐dependent enzymes. In particular, a flavoprotein monooxygenase proved critical for the drastic oxidative rearrangement of a pentangular precursor and the installment of an intermediate [6,6]‐spiroketal moiety. Here we provide structural and mechanistic insights into the control of catalysis by this spiroketal synthase, which fulfills several important functions as reductase, monooxygenase, and presumably oxidase. The enzyme hereby tightly controls the redox state of the substrate to counteract shunt product formation, while also steering the cleavage of three carbon‐carbon bonds. Our work illustrates an exceptional strategy for the biosynthesis of stable chroman spiroketals.
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Affiliation(s)
- Marina Toplak
- Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104, Freiburg, Germany
| | - Raspudin Saleem-Batcha
- Institute of Pharmaceutical Sciences, University of Freiburg, Albertstr. 25, 79104, Freiburg, Germany
| | - Jörn Piel
- Institute of Microbiology, Eidgenössische Technische Hochschule (ETH) Zürich, 8093, Zürich, Switzerland
| | - Robin Teufel
- Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104, Freiburg, Germany
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32
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Toplak M, Saleem‐Batcha R, Piel J, Teufel R. Catalytic Control of Spiroketal Formation in Rubromycin Polyketide Biosynthesis. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202109384] [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)
- Marina Toplak
- Faculty of Biology University of Freiburg Schänzlestrasse 1 79104 Freiburg Germany
| | - Raspudin Saleem‐Batcha
- Institute of Pharmaceutical Sciences University of Freiburg Albertstr. 25 79104 Freiburg Germany
| | - Jörn Piel
- Institute of Microbiology Eidgenössische Technische Hochschule (ETH) Zürich 8093 Zürich Switzerland
| | - Robin Teufel
- Faculty of Biology University of Freiburg Schänzlestrasse 1 79104 Freiburg Germany
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33
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Alvigini L, Gran-Scheuch A, Guo Y, Trajkovic M, Saifuddin M, Fraaije MW, Mattevi A. Discovery, Biocatalytic Exploration and Structural Analysis of a 4-Ethylphenol Oxidase from Gulosibacter chungangensis. Chembiochem 2021; 22:3225-3233. [PMID: 34523783 PMCID: PMC9293466 DOI: 10.1002/cbic.202100457] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 09/14/2021] [Indexed: 11/21/2022]
Abstract
The vanillyl‐alcohol oxidase (VAO) family is a rich source of biocatalysts for the oxidative bioconversion of phenolic compounds. Through genome mining and sequence comparisons, we found that several family members lack a generally conserved catalytic aspartate. This finding led us to study a VAO‐homolog featuring a glutamate residue in place of the common aspartate. This 4‐ethylphenol oxidase from Gulosibacter chungangensis (Gc4EO) shares 42 % sequence identity with VAO from Penicillium simplicissimum, contains the same 8α‐N3‐histidyl‐bound FAD and uses oxygen as electron acceptor. However, Gc4EO features a distinct substrate scope and product specificity as it is primarily effective in the dehydrogenation of para‐substituted phenols with little generation of hydroxylated products. The three‐dimensional structure shows that the characteristic glutamate side chain creates a closely packed environment that may limit water accessibility and thereby protect from hydroxylation. With its high thermal stability, well defined structural properties and high expression yields, Gc4EO may become a catalyst of choice for the specific dehydrogenation of phenolic compounds bearing small substituents.
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Affiliation(s)
- Laura Alvigini
- Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Via Ferrata 9, 27100, Pavia, Italy
| | - Alejandro Gran-Scheuch
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Yiming Guo
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Milos Trajkovic
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Mohammad Saifuddin
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Marco W Fraaije
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Andrea Mattevi
- Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Via Ferrata 9, 27100, Pavia, Italy
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34
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A shared mechanistic pathway for pyridoxal phosphate-dependent arginine oxidases. Proc Natl Acad Sci U S A 2021; 118:2012591118. [PMID: 34580201 DOI: 10.1073/pnas.2012591118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/21/2021] [Indexed: 01/02/2023] Open
Abstract
The mechanism by which molecular oxygen is activated by the organic cofactor pyridoxal phosphate (PLP) for oxidation reactions remains poorly understood. Recent work has identified arginine oxidases that catalyze desaturation or hydroxylation reactions. Here, we investigate a desaturase from the Pseudoalteromonas luteoviolacea indolmycin pathway. Our work, combining X-ray crystallographic, biochemical, spectroscopic, and computational studies, supports a shared mechanism with arginine hydroxylases, involving two rounds of single-electron transfer to oxygen and superoxide rebound at the 4' carbon of the PLP cofactor. The precise positioning of a water molecule in the active site is proposed to control the final reaction outcome. This proposed mechanism provides a unified framework to understand how oxygen can be activated by PLP-dependent enzymes for oxidation of arginine and elucidates a shared mechanistic pathway and intertwined evolutionary history for arginine desaturases and hydroxylases.
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35
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MdaB and NfrA, two novel reductases important in the survival and persistence of the major enteropathogen Campylobacter jejuni. J Bacteriol 2021; 204:e0042121. [PMID: 34606373 PMCID: PMC8765430 DOI: 10.1128/jb.00421-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The paralogues RrpA and RrpB, which are members of the MarR family of DNA binding proteins, are important for the survival of the global bacterial foodborne pathogen Campylobacter jejuni under redox stress. We report that RrpA is a positive regulator of mdaB, encoding a flavin-dependent quinone reductase that contributes to the protection from redox stress mediated by structurally diverse quinones, while RrpB negatively regulates the expression of cj1555c (renamed nfrA for NADPH-flavin reductase A), encoding a flavin reductase. NfrA reduces riboflavin at a greater rate than its derivatives, suggesting that exogenous free flavins are the natural substrate. MdaB and NfrA both prefer NADPH as an electron donor. Cysteine substitution and posttranslational modification analyses indicated that RrpA and RrpB employ a cysteine-based redox switch. Complete genome sequence analyses revealed that mdaB is frequently found in Campylobacter and related Helicobacter spp., while nfrA is predominant in C. jejuni strains. Quinones and flavins are redox cycling agents secreted by a wide range of cell types that can form damaging superoxide by one-electron reactions. We propose a model for stress adaptation where MdaB and NfrA facilitate a two-electron reduction mechanism to the less toxic hydroquinones, thus aiding survival and persistence of this major pathogen. IMPORTANCE Changes in cellular redox potential result in alteration in the oxidation state of intracellular metabolites and enzymes; consequently, cells make adjustments that favor growth and survival. The work we present here answers some of the many questions that have remained elusive over the years of investigation into the enigmatic microaerophile bacterium Campylobacter jejuni. We employed molecular approaches to understand the regulation mechanisms and functional analyses to reveal the roles of two novel quinone and flavin reductases; both serve as major pools of cellular redox-active molecules. This work extends our knowledge on bacterial redox sensing mechanisms and the significance of hemostasis.
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36
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37
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Matthews A, Schönfelder J, Lagies S, Schleicher E, Kammerer B, Ellis HR, Stull F, Teufel R. Bacterial flavoprotein monooxygenase YxeK salvages toxic S-(2-succino)-adducts via oxygenolytic C-S bond cleavage. FEBS J 2021; 289:787-807. [PMID: 34510734 DOI: 10.1111/febs.16193] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 08/18/2021] [Accepted: 09/09/2021] [Indexed: 01/23/2023]
Abstract
Thiol-containing nucleophiles such as cysteine react spontaneously with the citric acid cycle intermediate fumarate to form S-(2-succino)-adducts. In Bacillus subtilis, a salvaging pathway encoded by the yxe operon has recently been identified for the detoxification and exploitation of these compounds as sulfur sources. This route involves acetylation of S-(2-succino)cysteine to N-acetyl-2-succinocysteine, which is presumably converted to oxaloacetate and N-acetylcysteine, before a final deacetylation step affords cysteine. The critical oxidative cleavage of the C-S bond of N-acetyl-S-(2-succino)cysteine was proposed to depend on the predicted flavoprotein monooxygenase YxeK. Here, we characterize YxeK and verify its role in S-(2-succino)-adduct detoxification and sulfur metabolism. Detailed biochemical and mechanistic investigation of YxeK including 18 O-isotope-labeling experiments, homology modeling, substrate specificity tests, site-directed mutagenesis, and (pre-)steady-state kinetics provides insight into the enzyme's mechanism of action, which may involve a noncanonical flavin-N5-peroxide species for C-S bond oxygenolysis.
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Affiliation(s)
| | | | - Simon Lagies
- Institute of Organic Chemistry, University of Freiburg, Germany
| | - Erik Schleicher
- Institute of Physical Chemistry, University of Freiburg, Germany
| | - Bernd Kammerer
- Institute of Organic Chemistry, University of Freiburg, Germany.,BIOSS Center for Biological Signaling Studies, University of Freiburg, Germany
| | - Holly R Ellis
- Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - Frederick Stull
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, USA
| | - Robin Teufel
- Faculty of Biology, University of Freiburg, Germany
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38
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Duan Y, Toplak M, Hou A, Brock NL, Dickschat JS, Teufel R. A Flavoprotein Dioxygenase Steers Bacterial Tropone Biosynthesis via Coenzyme A-Ester Oxygenolysis and Ring Epoxidation. J Am Chem Soc 2021; 143:10413-10421. [PMID: 34196542 PMCID: PMC8283759 DOI: 10.1021/jacs.1c04996] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
![]()
Bacterial tropone
natural products such as tropolone, tropodithietic
acid, or the roseobacticides play crucial roles in various terrestrial
and marine symbiotic interactions as virulence factors, antibiotics,
algaecides, or quorum sensing signals. We now show that their poorly
understood biosynthesis depends on a shunt product from aerobic CoA-dependent
phenylacetic acid catabolism that is salvaged by the dedicated acyl-CoA
dehydrogenase-like flavoenzyme TdaE. Further characterization of TdaE
revealed an unanticipated complex catalysis, comprising substrate
dehydrogenation, noncanonical CoA-ester oxygenolysis, and final ring
epoxidation. The enzyme thereby functions as an archetypal flavoprotein
dioxygenase that incorporates both oxygen atoms from O2 into the substrate, most likely involving flavin-N5-peroxide and
flavin-N5-oxide species for consecutive CoA-ester cleavage and epoxidation,
respectively. The subsequent spontaneous decarboxylation of the reactive
enzyme product yields tropolone, which serves as a key virulence factor
in rice panicle blight caused by pathogenic edaphic Burkholderia
plantarii. Alternatively, the TdaE product is most likely
converted to more complex sulfur-containing secondary metabolites
such as tropodithietic acid from predominant marine Rhodobacteraceae (e.g., Phaeobacter inhibens).
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Affiliation(s)
- Ying Duan
- Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Marina Toplak
- Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Anwei Hou
- Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany
| | - Nelson L Brock
- Institute of Organic Chemistry, TU Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
| | - Jeroen S Dickschat
- Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany.,Institute of Organic Chemistry, TU Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
| | - Robin Teufel
- Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany
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39
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Pimviriyakul P, Jaruwat A, Chitnumsub P, Chaiyen P. Structural insights into a flavin-dependent dehalogenase HadA explain catalysis and substrate inhibition via quadruple π-stacking. J Biol Chem 2021; 297:100952. [PMID: 34252455 PMCID: PMC8342789 DOI: 10.1016/j.jbc.2021.100952] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 06/24/2021] [Accepted: 07/08/2021] [Indexed: 12/20/2022] Open
Abstract
HadA is a flavin-dependent monooxygenase catalyzing hydroxylation plus dehalogenation/denitration, which is useful for biodetoxification and biodetection. In this study, the X-ray structure of wild-type HadA (HadAWT) co-complexed with reduced FAD (FADH–) and 4-nitrophenol (4NP) (HadAWT−FADH–−4NP) was solved at 2.3-Å resolution, providing the first full package (with flavin and substrate bound) structure of a monooxygenase of this type. Residues Arg101, Gln158, Arg161, Thr193, Asp254, Arg233, and Arg439 constitute a flavin-binding pocket, whereas the 4NP-binding pocket contains the aromatic side chain of Phe206, which provides π-π stacking and also is a part of the hydrophobic pocket formed by Phe155, Phe286, Thr449, and Leu457. Based on site-directed mutagenesis and stopped-flow experiments, Thr193, Asp254, and His290 are important for C4a-hydroperoxyflavin formation with His290, also serving as a catalytic base for hydroxylation. We also identified a novel structural motif of quadruple π-stacking (π-π-π-π) provided by two 4NP and two Phe441 from two subunits. This motif promotes 4NP binding in a nonproductive dead-end complex, which prevents C4a-hydroperoxy-FAD formation when HadA is premixed with aromatic substrates. We also solved the structure of the HadAPhe441Val−FADH–−4NP complex at 2.3-Å resolution. Although 4NP can still bind to this variant, the quadruple π-stacking motif was disrupted. All HadAPhe441 variants lack substrate inhibition behavior, confirming that quadruple π-stacking is a main cause of dead-end complex formation. Moreover, the activities of these HadAPhe441 variants were improved by ⁓20%, suggesting that insights gained from the flavin-dependent monooxygenases illustrated here should be useful for future improvement of HadA’s biocatalytic applications.
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Affiliation(s)
- Panu Pimviriyakul
- Department of Biochemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Aritsara Jaruwat
- National Center for Genetic Engineering and Biotechnology, Pathumthani, Thailand
| | - Penchit Chitnumsub
- National Center for Genetic Engineering and Biotechnology, Pathumthani, Thailand.
| | - Pimchai Chaiyen
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand.
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40
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Smolyarova DD, Podgorny OV, Bilan DS, Belousov VV. A guide to genetically encoded tools for the study of H 2 O 2. FEBS J 2021; 289:5382-5395. [PMID: 34173331 DOI: 10.1111/febs.16088] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 04/23/2021] [Accepted: 06/24/2021] [Indexed: 01/09/2023]
Abstract
Cell metabolism heavily relies on the redox reactions that inevitably generate reactive oxygen species (ROS). It is now well established that ROS fluctuations near basal levels coordinate numerous physiological processes in living organisms, thus exhibiting regulatory functions. Hydrogen peroxide, the most long-lived ROS, is a key contributor to ROS-dependent signal transduction in the cell. H2 O2 is known to impact various targets in the cell; therefore, the question of how H2 O2 modulates physiological processes in a highly specific manner is central in redox biology. To resolve this question, novel genetic tools have recently been created for detecting H2 O2 and emulating its generation in living organisms with unmatched spatiotemporal resolution. Here, we review H2 O2 -sensitive genetically encoded fluorescent sensors and opto- and chemogenetic tools for controlled H2 O2 generation.
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Affiliation(s)
- Daria D Smolyarova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia.,Faculty of Biology, Lomonosov Moscow State University, Russia
| | - Oleg V Podgorny
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia.,Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, Moscow, Russia.,Laboratory of Experimental Oncology, Pirogov Russian National Research Medical University, Moscow, Russia
| | - Dmitry S Bilan
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia.,Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, Moscow, Russia.,Laboratory of Experimental Oncology, Pirogov Russian National Research Medical University, Moscow, Russia
| | - Vsevolod V Belousov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia.,Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, Moscow, Russia.,Laboratory of Experimental Oncology, Pirogov Russian National Research Medical University, Moscow, Russia.,Federal Center of Brain Research and Neurotechnologies of the Federal Medical Biological Agency, Moscow, Russia.,Institute for Cardiovascular Physiology, Georg August University Göttingen, Germany
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41
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Zadeh-Haghighi H, Simon C. Entangled radicals may explain lithium effects on hyperactivity. Sci Rep 2021; 11:12121. [PMID: 34108537 PMCID: PMC8190433 DOI: 10.1038/s41598-021-91388-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 05/26/2021] [Indexed: 02/05/2023] Open
Abstract
It is known that bipolar disorder and its lithium treatment involve the modulation of oxidative stress. Moreover, it has been observed that lithium's effects are isotope-dependent. Based on these findings, here we propose that lithium exerts its effects by influencing the recombination dynamics of a naturally occurring radical pair involving oxygen. We develop a simple model inspired by the radical-pair mechanism in cryptochrome in the context of avian magnetoreception and xenon-induced anesthesia. Our model reproduces the observed isotopic dependence in the lithium treatment of hyperactivity in rats. It predicts a magnetic-field dependence of the effectiveness of lithium, which provides one potential experimental test of our hypothesis. Our findings show that Nature might harness quantum entanglement for the brain's cognitive processes.
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Affiliation(s)
- Hadi Zadeh-Haghighi
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Institute for Quantum Science and Technology, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Quantum Alberta, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 1N4, Canada.
| | - Christoph Simon
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Institute for Quantum Science and Technology, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Quantum Alberta, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 1N4, Canada.
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42
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Vanoni MA. Iron-sulfur flavoenzymes: the added value of making the most ancient redox cofactors and the versatile flavins work together. Open Biol 2021; 11:210010. [PMID: 33947244 PMCID: PMC8097209 DOI: 10.1098/rsob.210010] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Iron-sulfur (Fe-S) flavoproteins form a broad and growing class of complex, multi-domain and often multi-subunit proteins coupling the most ancient cofactors (the Fe-S clusters) and the most versatile coenzymes (the flavin coenzymes, FMN and FAD). These enzymes catalyse oxidoreduction reactions usually acting as switches between donors of electron pairs and acceptors of single electrons, and vice versa. Through selected examples, the enzymes' structure−function relationships with respect to rate and directionality of the electron transfer steps, the role of the apoprotein and its dynamics in modulating the electron transfer process will be discussed.
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Affiliation(s)
- Maria Antonietta Vanoni
- Dipartimento di Bioscienze, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy
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43
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Ortega P, Gil-Guerrero S, Veselinova A, Zanchet A, González-Sánchez L, Jambrina PG, Sanz-Sanz C. Multi- and single-reference methods for the analysis of multi-state peroxidation of enolates. J Chem Phys 2021; 154:144303. [PMID: 33858147 DOI: 10.1063/5.0046906] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In spite of being spin-forbidden, some enzymes are capable of catalyzing the incorporation of O2(Σg-3) to organic substrates without needing any cofactor. It has been established that the process followed by these enzymes starts with the deprotonation of the substrate forming an enolate. In a second stage, the peroxidation of the enolate formation occurs, a process in which the system changes its spin multiplicity from a triplet state to a singlet state. In this article, we study the addition of O2 to enolates using state-of-the-art multi-reference and single-reference methods. Our results confirm that intersystem crossing is promoted by stabilization of the singlet state along the reaction path. When multi-reference methods are used, large active spaces are required, and in this situation, semistochastic heat-bath configuration interaction emerges as a powerful method to study these multi-configurational systems and is in good agreement with PNO-LCCSD(T) when the system is well-represented by a single-configuration.
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Affiliation(s)
- P Ortega
- Departamento de Química-Física, University of Salamanca, Salamanca 37008, Spain
| | - S Gil-Guerrero
- Departamento de Química-Física, University of Salamanca, Salamanca 37008, Spain
| | - A Veselinova
- Departamento de Química-Física, University of Salamanca, Salamanca 37008, Spain
| | - A Zanchet
- Instituto de Física Fundamental (CSIC), Madrid 28006, Spain
| | - L González-Sánchez
- Departamento de Química-Física, University of Salamanca, Salamanca 37008, Spain
| | - P G Jambrina
- Departamento de Química-Física, University of Salamanca, Salamanca 37008, Spain
| | - C Sanz-Sanz
- Departamento de Química Física Aplicada. Universidad Autónoma de Madrid, Madrid 28049, Spain
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44
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Lahham M, Jha S, Goj D, Macheroux P, Wallner S. The family of sarcosine oxidases: Same reaction, different products. Arch Biochem Biophys 2021; 704:108868. [PMID: 33812916 DOI: 10.1016/j.abb.2021.108868] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/26/2021] [Accepted: 03/27/2021] [Indexed: 12/11/2022]
Abstract
The subfamily of sarcosine oxidase is a set of enzymes within the larger family of amine oxidases. It is ubiquitously distributed among different kingdoms of life. The member enzymes catalyze the oxidization of an N-methyl amine bond of amino acids to yield unstable imine species that undergo subsequent spontaneous non-enzymatic reactions, forming an array of different products. These products range from demethylated simple species to complex alkaloids. The enzymes belonging to the sarcosine oxidase family, namely, monomeric and heterotetrameric sarcosine oxidase, l-pipecolate oxidase, N-methyltryptophan oxidase, NikD, l-proline dehydrogenase, FsqB, fructosamine oxidase and saccharopine oxidase have unique features differentiating them from other amine oxidases. This review highlights the key attributes of the sarcosine oxidase family enzymes, in terms of their substrate binding motif, type of oxidation reaction mediated and FAD regeneration, to define the boundaries of this group and demarcate these enzymes from other amine oxidase families.
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Affiliation(s)
- Majd Lahham
- Institute of Biochemistry, Graz University of Technology, NAWI Graz, Graz, Austria; Department of Biochemistry and Microbiology, Aljazeera Private University, Ghabagheb, Syria
| | - Shalinee Jha
- Institute of Biochemistry, Graz University of Technology, NAWI Graz, Graz, Austria
| | - Dominic Goj
- Institute of Biochemistry, Graz University of Technology, NAWI Graz, Graz, Austria
| | - Peter Macheroux
- Institute of Biochemistry, Graz University of Technology, NAWI Graz, Graz, Austria
| | - Silvia Wallner
- Institute of Biochemistry, Graz University of Technology, NAWI Graz, Graz, Austria.
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45
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Dulchavsky M, Clark CT, Bardwell JCA, Stull F. A cytochrome c is the natural electron acceptor for nicotine oxidoreductase. Nat Chem Biol 2021; 17:344-350. [PMID: 33432238 PMCID: PMC7904663 DOI: 10.1038/s41589-020-00712-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 11/02/2020] [Accepted: 11/17/2020] [Indexed: 01/28/2023]
Abstract
Nicotine oxidoreductase (NicA2), a member of the flavin-containing amine oxidase family, is of medical relevance as it shows potential as a therapeutic to aid cessation of smoking due to its ability to oxidize nicotine into a non-psychoactive metabolite. However, the use of NicA2 in this capacity is stymied by its dismal O2-dependent activity. Unlike other enzymes in the amine oxidase family, NicA2 reacts very slowly with O2, severely limiting its nicotine-degrading activity. Instead of using O2 as an oxidant, we discovered that NicA2 donates electrons to a cytochrome c, which means that NicA2 is actually a dehydrogenase. This is surprising, as enzymes of the flavin-containing amine oxidase family were invariably thought to use O2 as an electron acceptor. Our findings establish new perspectives for engineering this potentially useful therapeutic and prompt a reconsideration of the term 'oxidase' in referring to members of the flavin-containing amine 'oxidase' family.
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Affiliation(s)
- Mark Dulchavsky
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA.,Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, USA
| | | | - James C. A. Bardwell
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA.,Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA., or
| | - Frederick Stull
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, USA., or
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46
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Reis RAG, Li H, Johnson M, Sobrado P. New frontiers in flavin-dependent monooxygenases. Arch Biochem Biophys 2021; 699:108765. [PMID: 33460580 DOI: 10.1016/j.abb.2021.108765] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 01/08/2021] [Accepted: 01/11/2021] [Indexed: 12/15/2022]
Abstract
Flavin-dependent monooxygenases catalyze a wide variety of redox reactions in important biological processes and are responsible for the synthesis of highly complex natural products. Although much has been learned about FMO chemistry in the last ~80 years of research, several aspects of the reactions catalyzed by these enzymes remain unknown. In this review, we summarize recent advancements in the flavin-dependent monooxygenase field including aspects of flavin dynamics, formation and stabilization of reactive species, and the hydroxylation mechanism. Novel catalysis of flavin-dependent N-oxidases involving consecutive oxidations of amines to generate oximes or nitrones is presented and the biological relevance of the products is discussed. In addition, the activity of some FMOs have been shown to be essential for the virulence of several human pathogens. We also discuss the biomedical relevance of FMOs in antibiotic resistance and the efforts to identify inhibitors against some members of this important and growing family enzymes.
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Affiliation(s)
| | - Hao Li
- Department of Biochemistry, Blacksburg, VA, 24061, USA
| | - Maxim Johnson
- Department of Biochemistry, Blacksburg, VA, 24061, USA
| | - Pablo Sobrado
- Department of Biochemistry, Blacksburg, VA, 24061, USA; Center for Drug Discovery, Virginia Tech, Blacksburg, VA, 24061, USA.
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47
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Naramittanakul A, Buttranon S, Petchsuk A, Chaiyen P, Weeranoppanant N. Development of a continuous-flow system with immobilized biocatalysts towards sustainable bioprocessing. REACT CHEM ENG 2021. [DOI: 10.1039/d1re00189b] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Implementing immobilized biocatalysts in continuous-flow systems can enable a sustainable process through enhanced enzyme stability, better transport and process continuity as well as simplified recycle and downstream processing.
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Affiliation(s)
- Apisit Naramittanakul
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong 21210, Thailand
| | - Supacha Buttranon
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong 21210, Thailand
| | - Atitsa Petchsuk
- National Metal and Materials Technology Center (MTEC), Pathum Thani 12120, Thailand
| | - Pimchai Chaiyen
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong 21210, Thailand
| | - Nopphon Weeranoppanant
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong 21210, Thailand
- Department of Chemical Engineering, Faculty of Engineering, Burapha University, Chonburi 20131, Thailand
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48
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Toplak M, Matthews A, Teufel R. The devil is in the details: The chemical basis and mechanistic versatility of flavoprotein monooxygenases. Arch Biochem Biophys 2020; 698:108732. [PMID: 33358998 DOI: 10.1016/j.abb.2020.108732] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 12/15/2020] [Accepted: 12/19/2020] [Indexed: 02/07/2023]
Abstract
The ubiquitous flavoenzymes commonly catalyze redox chemistry such as the monooxygenation of organic substrates and are both widely utilized in nature (e.g., in primary and secondary metabolism) and of significant industrial interest. In this work, we highlight the structural and mechanistic characteristics of the distinct types of flavoprotein monooxygenases (FPMOs). We thereby illustrate the chemical basis of FPMO catalysis, which enables reactions such as (aromatic) hydroxylation, epoxidation, (de)halogenation, heteroatom oxygenation, Baeyer-Villiger oxidation, α-hydroxylation of ketones, or non-oxidative carbon-hetero bond cleavage. This seemingly unmatched versatility in oxygenation chemistry results from extensive fine-tuning and regiospecific functionalization of the flavin cofactor that is tightly controlled by the surrounding protein matrix. Accordingly, FPMOs steer the formation of covalent flavin-oxygen adducts for oxygen transfer in the form of the classical flavin-C4a-(hydro)peroxide or the recently discovered N5-functionalized flavins (i.e. the flavin-N5-oxide and the flavin-N5-peroxide), while in rare cases covalent oxygen adduct formation may be foregone entirely. Finally, we speculate about hitherto undiscovered flavin-mediated oxygenation reactions and compare FPMOs to cytochrome P450 monooxygenases, before addressing open questions and challenges for the future investigation of FPMOs.
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Affiliation(s)
- Marina Toplak
- Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | - Arne Matthews
- Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | - Robin Teufel
- Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany.
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49
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Tinikul R, Lawan N, Akeratchatapan N, Pimviriyakul P, Chinantuya W, Suadee C, Sucharitakul J, Chenprakhon P, Ballou DP, Entsch B, Chaiyen P. Protonation status and control mechanism of flavin-oxygen intermediates in the reaction of bacterial luciferase. FEBS J 2020; 288:3246-3260. [PMID: 33289305 DOI: 10.1111/febs.15653] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 11/15/2020] [Accepted: 11/30/2020] [Indexed: 12/14/2022]
Abstract
Bacterial luciferase catalyzes a bioluminescent reaction by oxidizing long-chain aldehydes to acids using reduced FMN and oxygen as co-substrates. Although a flavin C4a-peroxide anion is postulated to be the intermediate reacting with aldehyde prior to light liberation, no clear identification of the protonation status of this intermediate has been reported. Here, transient kinetics, pH variation, and site-directed mutagenesis were employed to probe the protonation state of the flavin C4a-hydroperoxide in bacterial luciferase. The first observed intermediate, with a λmax of 385 nm, transformed to an intermediate with a λmax of 375 nm. Spectra of the first observed intermediate were pH-dependent, with a λmax of 385 nm at pH < 8.5 and 375 at pH > 9, correlating with a pKa of 7.7-8.1. These data are consistent with the first observed flavin C4a intermediate at pH < 8.5 being the protonated flavin C4a-hydroperoxide, which loses a proton to become an active flavin C4a-peroxide. Stopped-flow studies of His44Ala, His44Asp, and His44Asn variants showed only a single intermediate with a λmax of 385 nm at all pH values, and none of these variants generate light. These data indicate that His44 variants only form a flavin C4a-hydroperoxide, but not an active flavin C4a-peroxide, indicating an essential role for His44 in deprotonating the flavin C4a-hydroperoxide and initiating chemical catalysis. We also investigated the function of the adjacent His45; stopped-flow data and molecular dynamics simulations identify the role of this residue in binding reduced FMN.
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Affiliation(s)
- Ruchanok Tinikul
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Narin Lawan
- Department of Chemistry, Faculty of Science, Chiangmai University, Thailand
| | - Nattanon Akeratchatapan
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Panu Pimviriyakul
- Department of Biochemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Wachirawit Chinantuya
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Chutintorn Suadee
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Jeerus Sucharitakul
- Department of Biochemistry, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - Pirom Chenprakhon
- Institute for Innovative Learning, Mahidol University, Nakhon Pathom, Thailand
| | - David P Ballou
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Barrie Entsch
- School of Science and Technology, University of New England, Armidale, NSW, Australia
| | - Pimchai Chaiyen
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand.,School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
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50
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Abstract
Many flavin-dependent phenolic hydroxylases (monooxygenases) have been extensively investigated. Their crystal structures and reaction mechanisms are well understood. These enzymes belong to groups A and D of the flavin-dependent monooxygenases and can be classified as single-component and two-component flavin-dependent monooxygenases. The insertion of molecular oxygen into the substrates catalyzed by these enzymes is beneficial for modifying the biological properties of phenolic compounds and their derivatives. This chapter provides an in-depth discussion of the structural features of single-component and two-component flavin-dependent phenolic hydroxylases. The reaction mechanisms of selected enzymes, including 3-hydroxy-benzoate 4-hydroxylase (PHBH) and 3-hydroxy-benzoate 6-hydroxylase as representatives of single-component enzymes and 3-hydroxyphenylacetate 4-hydroxylase (HPAH) as a representative of two-component enzymes, are discussed in detail. This chapter comprises the following four main parts: general reaction, structures, reaction mechanisms, and enzyme engineering for biocatalytic applications. Enzymes belonging to the same group catalyze similar reactions but have different unique structural features to control their reactivity to substrates and the formation and stabilization of C4a-hydroperoxyflavin. Protein engineering has been employed to improve the ability to use these enzymes to synthesize valuable compounds. A thorough understanding of the structural and mechanistic features controlling enzyme reactivity is useful for enzyme redesign and enzyme engineering for future biocatalytic applications.
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Affiliation(s)
- Pirom Chenprakhon
- Institute for Innovative Learning, Mahidol University, Nakhon Pathom, Thailand.
| | - Panu Pimviriyakul
- Department of Biochemistry, Faculty of Science, Kasetsart University, Chatuchak, Bangkok, Thailand; Department of Biotechnology, Faculty of Engineering and Industrial Technology, Silpakorn University, Nakhon Pathom, Thailand
| | - Chanakan Tongsook
- Department of Chemistry, Faculty of Science, Silpakorn University, Nakhon Pathom, Thailand
| | - Pimchai Chaiyen
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Rayong, Thailand
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