1
|
Bopp C, Bernet NM, Meyer F, Khan R, Robinson SL, Kohler HPE, Buller R, Hofstetter TB. Elucidating the Role of O 2 Uncoupling for the Adaptation of Bacterial Biodegradation Reactions Catalyzed by Rieske Oxygenases. ACS ENVIRONMENTAL AU 2024; 4:204-218. [PMID: 39035869 PMCID: PMC11258757 DOI: 10.1021/acsenvironau.4c00016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 04/26/2024] [Accepted: 04/26/2024] [Indexed: 07/23/2024]
Abstract
Oxygenation of aromatic and aliphatic hydrocarbons by Rieske oxygenases is the initial step of various biodegradation pathways for environmental organic contaminants. Microorganisms carrying Rieske oxygenases are able to quickly adapt their substrate spectra to alternative carbon and energy sources that are structurally related to the original target substrate, yet the molecular events responsible for this rapid adaptation are not well understood. Here, we evaluated the hypothesis that reactive oxygen species (ROS) generated by unproductive activation of O2, the so-called O2 uncoupling, in the presence of the alternative substrate exert a selective pressure on the bacterium for increasing the oxygenation efficiency of Rieske oxygenases. To that end, we studied wild-type 2-nitrotoluene dioxygenase from Acidovorax sp. strain JS42 and five enzyme variants that have evolved from adaptive laboratory evolution experiments with 3- and 4-nitrotoluene as alternative growth substrates. The enzyme variants showed a substantially increased oxygenation efficiency toward the new target substrates concomitant with a reduction of ROS production, while mechanisms and kinetics of enzymatic O2 activation remained unchanged. Structural analyses and docking studies suggest that amino acid substitutions in enzyme variants occurred at residues lining both substrate and O2 transport tunnels, enabling tighter binding of the target substrates in the active site. Increased oxygenation efficiencies measured in vitro for the various enzyme (variant)-substrate combinations correlated linearly with in vivo changes in growth rates for evolved Acidovorax strains expressing the variants. Our data suggest that the selective pressure from oxidative stress toward more efficient oxygenation by Rieske oxygenases was most notable when O2 uncoupling exceeded 60%.
Collapse
Affiliation(s)
- Charlotte
E. Bopp
- Eawag,
Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Institute
of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, 8092 Zürich, Switzerland
| | - Nora M. Bernet
- Eawag,
Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Institute
of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, 8092 Zürich, Switzerland
| | - Fabian Meyer
- Competence
Center for Biocatalysis, Institute of Chemistry and Biotechnology, Zürich University of Applied Sciences, 8820 Wädenswil, Switzerland
| | - Riyaz Khan
- Eawag,
Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Serina L. Robinson
- Eawag,
Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Hans-Peter E. Kohler
- Eawag,
Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Rebecca Buller
- Competence
Center for Biocatalysis, Institute of Chemistry and Biotechnology, Zürich University of Applied Sciences, 8820 Wädenswil, Switzerland
| | - Thomas B. Hofstetter
- Eawag,
Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Institute
of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, 8092 Zürich, Switzerland
| |
Collapse
|
2
|
Zhu W, Wu P, Larson VA, Kumar A, Li XX, Seo MS, Lee YM, Wang B, Lehnert N, Nam W. Electronic Structure and Reactivity of Mononuclear Nonheme Iron-Peroxo Complexes as a Biomimetic Model of Rieske Oxygenases: Ring Size Effects of Macrocyclic Ligands. J Am Chem Soc 2024; 146:250-262. [PMID: 38147793 DOI: 10.1021/jacs.3c08559] [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: 12/28/2023]
Abstract
We report the macrocyclic ring size-electronic structure-electrophilic reactivity correlation of mononuclear nonheme iron(III)-peroxo complexes bearing N-tetramethylated cyclam analogues (n-TMC), [FeIII(O2)(12-TMC)]+ (1), [FeIII(O2)(13-TMC)]+ (2), and [FeIII(O2)(14-TMC)]+ (3), as a model study of Rieske oxygenases. The Fe(III)-peroxo complexes show the same δ and pseudo-σ bonds between iron and the peroxo ligand. However, the strength of these interactions varies depending on the ring size of the n-TMC ligands; the overall Fe-O bond strength and the strength of the Fe-O2 δ bond increase gradually as the ring size of the n-TMC ligands becomes smaller, such as from 14-TMC to 13-TMC to 12-TMC. MCD spectroscopy plays a key role in assigning the characteristic low-energy δ → δ* LMCT band, which provides direct insight into the strength of the Fe-O2 δ bond and which, in turn, is correlated with the superoxo character of the iron-peroxo group. In oxidation reactions, reactivities of 1-3 toward hydrocarbon C-H bond activation are compared, revealing the reactivity order of 1 > 2 > 3; the [FeIII(O2)(n-TMC)]+ complex with a smaller n-TMC ring size, 12-TMC, is much more reactive than that with a larger n-TMC ring size, 14-TMC. DFT analysis shows that the Fe(III)-peroxo complex is not reactive toward C-H bonds, but it is the end-on Fe(II)-superoxo valence tautomer that is responsible for the observed reactivity. The hydrogen atom abstraction (HAA) reactivity of these intermediates is correlated with the overall donicity of the n-TMC ligand, which modulates the energy of the singly occupied π* superoxo frontier orbital that serves as the electron acceptor in the HAA reaction. The implications of these results for the mechanism of Rieske oxygenases are further discussed.
Collapse
Affiliation(s)
- Wenjuan Zhu
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Peng Wu
- State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering, School of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, P. R. China
| | - Virginia A Larson
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Akhilesh Kumar
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Xiao-Xi Li
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
- Institute of Molecular Sciences and Engineering, Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao 266237, P. R. China
| | - Mi Sook Seo
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Yong-Min Lee
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Binju Wang
- 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
| | - Nicolai Lehnert
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Wonwoo Nam
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
- College of Chemistry and Chemical Engineering, Yan'an University, Yan'an, Shaanxi Province 716000, P. R. China
| |
Collapse
|
3
|
Guth FM, Lindner F, Rydzek S, Peil A, Friedrich S, Hauer B, Hahn F. Rieske Oxygenase-Catalyzed Oxidative Late-Stage Functionalization during Complex Antifungal Polyketide Biosynthesis. ACS Chem Biol 2023; 18:2450-2456. [PMID: 37948749 DOI: 10.1021/acschembio.3c00498] [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: 11/12/2023]
Abstract
Rieske oxygenases (ROs) from natural product biosynthetic pathways are a poorly studied group of enzymes with significant potential as oxidative functionalization biocatalysts. A study on the ROs JerL, JerP, and AmbP from the biosynthetic pathways of jerangolid A and ambruticin VS-3 is described. Their activity was successfully reconstituted using whole-cell bioconversion systems coexpressing the ROs and their respective natural flavin-dependent reductase (FDR) partners. Feeding authentic biosynthetic intermediates and synthetic surrogates to these strains confirmed the involvement of the ROs in hydroxymethylpyrone and dihydropyran formation and revealed crucial information about the RO's substrate specificity. The pronounced dependence of JerL and JerP on the presence of a methylenolether allowed the precise temporal assignment of RO catalysis to the ultimate steps of jerangolid biosynthesis. JerP and AmbP stand out among the biosynthetic ROs studied so far for their ability to catalyze clean tetrahydropyran desaturation without further functionalizing the formed electron-rich double bonds. This work highlights the remarkable ability of ROs to highly selectively oxidize complex molecular scaffolds.
Collapse
Affiliation(s)
- Florian M Guth
- Professur für Organische Chemie (Lebensmittelchemie), Fakultät für Biologie, Chemie und Geowissenschaften, Department of Chemistry, Universität Bayreuth, 95447 Bayreuth, Germany
| | - Frederick Lindner
- Professur für Organische Chemie (Lebensmittelchemie), Fakultät für Biologie, Chemie und Geowissenschaften, Department of Chemistry, Universität Bayreuth, 95447 Bayreuth, Germany
| | - Simon Rydzek
- Professur für Organische Chemie (Lebensmittelchemie), Fakultät für Biologie, Chemie und Geowissenschaften, Department of Chemistry, Universität Bayreuth, 95447 Bayreuth, Germany
| | - Andreas Peil
- Professur für Organische Chemie (Lebensmittelchemie), Fakultät für Biologie, Chemie und Geowissenschaften, Department of Chemistry, Universität Bayreuth, 95447 Bayreuth, Germany
| | - Steffen Friedrich
- Professur für Organische Chemie (Lebensmittelchemie), Fakultät für Biologie, Chemie und Geowissenschaften, Department of Chemistry, Universität Bayreuth, 95447 Bayreuth, Germany
| | - Bernhard Hauer
- Institute of Technical Biochemistry, Universität Stuttgart, Allmandring 31, 70569 Stuttgart, Germany
| | - Frank Hahn
- Professur für Organische Chemie (Lebensmittelchemie), Fakultät für Biologie, Chemie und Geowissenschaften, Department of Chemistry, Universität Bayreuth, 95447 Bayreuth, Germany
| |
Collapse
|
4
|
Tian J, Boggs DG, Donnan PH, Barroso GT, Garcia AA, Dowling DP, Buss JA, Bridwell-Rabb J. The NADH recycling enzymes TsaC and TsaD regenerate reducing equivalents for Rieske oxygenase chemistry. J Biol Chem 2023; 299:105222. [PMID: 37673337 PMCID: PMC10579966 DOI: 10.1016/j.jbc.2023.105222] [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: 05/27/2023] [Revised: 08/22/2023] [Accepted: 08/31/2023] [Indexed: 09/08/2023] Open
Abstract
Many microorganisms use both biological and nonbiological molecules as sources of carbon and energy. This resourcefulness means that some microorganisms have mechanisms to assimilate pollutants found in the environment. One such organism is Comamonas testosteroni, which metabolizes 4-methylbenzenesulfonate and 4-methylbenzoate using the TsaMBCD pathway. TsaM is a Rieske oxygenase, which in concert with the reductase TsaB consumes a molar equivalent of NADH. Following this step, the annotated short-chain dehydrogenase/reductase and aldehyde dehydrogenase enzymes TsaC and TsaD each regenerate a molar equivalent of NADH. This co-occurrence ameliorates the need for stoichiometric addition of reducing equivalents and thus represents an attractive strategy for integration of Rieske oxygenase chemistry into biocatalytic applications. Therefore, in this work, to overcome the lack of information regarding NADH recycling enzymes that function in partnership with Rieske non-heme iron oxygenases (Rieske oxygenases), we solved the X-ray crystal structure of TsaC to a resolution of 2.18 Å. Using this structure, a series of substrate analog and protein variant combination reactions, and differential scanning fluorimetry experiments, we identified active site features involved in binding NAD+ and controlling substrate specificity. Further in vitro enzyme cascade experiments demonstrated the efficient TsaC- and TsaD-mediated regeneration of NADH to support Rieske oxygenase chemistry. Finally, through in-depth bioinformatic analyses, we illustrate the widespread co-occurrence of Rieske oxygenases with TsaC-like enzymes. This work thus demonstrates the utility of these NADH recycling enzymes and identifies a library of short-chain dehydrogenase/reductase enzyme prospects that can be used in Rieske oxygenase pathways for in situ regeneration of NADH.
Collapse
Affiliation(s)
- Jiayi Tian
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA
| | - David G Boggs
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA
| | - Patrick H Donnan
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA
| | - Gage T Barroso
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA
| | | | - Daniel P Dowling
- Department of Chemistry, University of Massachusetts Boston, Boston, Massachusetts, USA
| | - Joshua A Buss
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA
| | | |
Collapse
|
5
|
Tian J, Liu J, Knapp M, Donnan PH, Boggs DG, Bridwell-Rabb J. Custom tuning of Rieske oxygenase reactivity. Nat Commun 2023; 14:5858. [PMID: 37730711 PMCID: PMC10511449 DOI: 10.1038/s41467-023-41428-x] [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: 11/13/2022] [Accepted: 08/27/2023] [Indexed: 09/22/2023] Open
Abstract
Rieske oxygenases use a Rieske-type [2Fe-2S] cluster and a mononuclear iron center to initiate a range of chemical transformations. However, few details exist regarding how this catalytic scaffold can be predictively tuned to catalyze divergent reactions. Therefore, in this work, using a combination of structural analyses, as well as substrate and rational protein-based engineering campaigns, we elucidate the architectural trends that govern catalytic outcome in the Rieske monooxygenase TsaM. We identify structural features that permit a substrate to be functionalized by TsaM and pinpoint active-site residues that can be targeted to manipulate reactivity. Exploiting these findings allowed for custom tuning of TsaM reactivity: substrates are identified that support divergent TsaM-catalyzed reactions and variants are created that exclusively catalyze dioxygenation or sequential monooxygenation chemistry. Importantly, we further leverage these trends to tune the reactivity of additional monooxygenase and dioxygenase enzymes, and thereby provide strategies to custom tune Rieske oxygenase reaction outcomes.
Collapse
Affiliation(s)
- Jiayi Tian
- Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Jianxin Liu
- Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Madison Knapp
- Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Patrick H Donnan
- Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
| | - David G Boggs
- Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
| | | |
Collapse
|
6
|
Abstract
The ability to site-selectively modify equivalent functional groups in a molecule has the potential to streamline syntheses and increase product yields by lowering step counts. Enzymes catalyze site-selective transformations throughout primary and secondary metabolism, but leveraging this capability for non-native substrates and reactions requires a detailed understanding of the potential and limitations of enzyme catalysis and how these bounds can be extended by protein engineering. In this review, we discuss representative examples of site-selective enzyme catalysis involving functional group manipulation and C-H bond functionalization. We include illustrative examples of native catalysis, but our focus is on cases involving non-native substrates and reactions often using engineered enzymes. We then discuss the use of these enzymes for chemoenzymatic transformations and target-oriented synthesis and conclude with a survey of tools and techniques that could expand the scope of non-native site-selective enzyme catalysis.
Collapse
Affiliation(s)
- Dibyendu Mondal
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Harrison M Snodgrass
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Christian A Gomez
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Jared C Lewis
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| |
Collapse
|
7
|
Runda ME, de Kok NAW, Schmidt S. Rieske Oxygenases and Other Ferredoxin-Dependent Enzymes: Electron Transfer Principles and Catalytic Capabilities. Chembiochem 2023; 24:e202300078. [PMID: 36964978 DOI: 10.1002/cbic.202300078] [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: 01/31/2023] [Revised: 03/24/2023] [Accepted: 03/24/2023] [Indexed: 03/27/2023]
Abstract
Enzymes that depend on sophisticated electron transfer via ferredoxins (Fds) exhibit outstanding catalytic capabilities, but despite decades of research, many of them are still not well understood or exploited for synthetic applications. This review aims to provide a general overview of the most important Fd-dependent enzymes and the electron transfer processes involved. While several examples are discussed, we focus in particular on the family of Rieske non-heme iron-dependent oxygenases (ROs). In addition to illustrating their electron transfer principles and catalytic potential, the current state of knowledge on structure-function relationships and the mode of interaction between the redox partner proteins is reviewed. Moreover, we highlight several key catalyzed transformations, but also take a deeper dive into their engineerability for biocatalytic applications. The overall findings from these case studies highlight the catalytic capabilities of these biocatalysts and could stimulate future interest in developing additional Fd-dependent enzyme classes for synthetic applications.
Collapse
Affiliation(s)
- Michael E Runda
- Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy, University of Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Niels A W de Kok
- Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy, University of Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Sandy Schmidt
- Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy, University of Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| |
Collapse
|
8
|
Tian J, Garcia AA, Donnan PH, Bridwell-Rabb J. Leveraging a Structural Blueprint to Rationally Engineer the Rieske Oxygenase TsaM. Biochemistry 2023. [PMID: 37188334 DOI: 10.1021/acs.biochem.3c00150] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Rieske nonheme iron oxygenases use two metallocenters, a Rieske-type [2Fe-2S] cluster and a mononuclear iron center, to catalyze oxidation reactions on a broad range of substrates. These enzymes are widely used by microorganisms to degrade environmental pollutants and to build complexity in a myriad of biosynthetic pathways that are industrially interesting. However, despite the value of this chemistry, there is a dearth of understanding regarding the structure-function relationships in this enzyme class, which limits our ability to rationally redesign, optimize, and ultimately exploit the chemistry of these enzymes. Therefore, in this work, by leveraging a combination of available structural information and state-of-the-art protein modeling tools, we show that three "hotspot" regions can be targeted to alter the site selectivity, substrate preference, and substrate scope of the Rieske oxygenase p-toluenesulfonate methyl monooxygenase (TsaM). Through mutation of six to 10 residues distributed between three protein regions, TsaM was engineered to behave as either vanillate monooxygenase (VanA) or dicamba monooxygenase (DdmC). This engineering feat means that TsaM was rationally engineered to catalyze an oxidation reaction at the meta and ortho positions of an aromatic substrate, rather than its favored native para position, and that TsaM was redesigned to perform chemistry on dicamba, a substrate that is not natively accepted by the enzyme. This work thus contributes to unlocking our understanding of structure-function relationships in the Rieske oxygenase enzyme class and expands foundational principles for future engineering of these metalloenzymes.
Collapse
Affiliation(s)
- Jiayi Tian
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | | | - Patrick H Donnan
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Jennifer Bridwell-Rabb
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| |
Collapse
|
9
|
Engineering Rieske oxygenase activity one piece at a time. Curr Opin Chem Biol 2023; 72:102227. [PMID: 36410250 PMCID: PMC9939785 DOI: 10.1016/j.cbpa.2022.102227] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/04/2022] [Accepted: 10/11/2022] [Indexed: 11/19/2022]
Abstract
Enzyme engineering plays a central role in the development of biocatalysts for biotechnology, chemical and pharmaceutical manufacturing, and environmental remediation. Rational design of proteins has historically relied on targeting active site residues to confer a protein with desirable catalytic properties. However, additional "hotspots" are also known to exist beyond the active site. Structural elements such as subunit-subunit interactions, entrance tunnels, and flexible loops influence enzyme catalysis and serve as potential "hotspots" for engineering. For the Rieske oxygenases, which use a Rieske cluster and mononuclear iron center to catalyze a challenging set of reactions, these outside of the active site regions are increasingly being shown to drive catalytic outcomes. Therefore, here, we highlight recent work on structurally characterized Rieske oxygenases that implicates architectural pieces inside and outside of the active site as key dictators of catalysis, and we suggest that these features may warrant attention in efforts aimed at Rieske oxygenase engineering.
Collapse
|
10
|
Zhang J, Maggiolo AO, Alfonzo E, Mao R, Porter NJ, Abney N, Arnold FH. Chemodivergent C(sp 3)-H and C(sp 2)-H Cyanomethylation Using Engineered Carbene Transferases. Nat Catal 2023; 6:152-160. [PMID: 36875868 PMCID: PMC9983643 DOI: 10.1038/s41929-022-00908-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 12/09/2022] [Indexed: 01/21/2023]
Abstract
The ubiquity of C-H bonds presents an attractive opportunity to elaborate and build complexity in organic molecules. Methods for selective functionalization, however, often must differentiate among multiple chemically similar and, in some cases indistinguishable, C-H bonds. An advantage of enzymes is that they can be finely tuned using directed evolution to achieve control over divergent C-H functionalization pathways. Here, we demonstrate engineered enzymes that effect a new-to-nature C-H alkylation with unparalleled selectivity: two complementary carbene C-H transferases derived from a cytochrome P450 from Bacillus megaterium deliver an α-cyanocarbene into the α-amino C(sp3)-H bonds or the ortho-arene C(sp2)-H bonds of N-substituted arenes. These two transformations proceed via different mechanisms, yet only minimal changes to the protein scaffold (nine mutations, less than 2% of the sequence) were needed to adjust the enzyme's control over the site-selectivity of cyanomethylation. The X-ray crystal structure of the selective C(sp3)-H alkylase, P411-PFA, reveals an unprecedented helical disruption which alters the shape and electrostatics in the enzyme active site. Overall, this work demonstrates the advantages of enzymes as C-H functionalization catalysts for divergent molecular derivatization.
Collapse
Affiliation(s)
- Juner Zhang
- Division of Chemistry and Chemical Engineering, California Institute of Technology; Pasadena, California, United States
| | - Ailiena O. Maggiolo
- Division of Chemistry and Chemical Engineering, California Institute of Technology; Pasadena, California, United States
| | - Edwin Alfonzo
- Division of Chemistry and Chemical Engineering, California Institute of Technology; Pasadena, California, United States
| | - Runze Mao
- Division of Chemistry and Chemical Engineering, California Institute of Technology; Pasadena, California, United States
| | - Nicholas J. Porter
- Division of Chemistry and Chemical Engineering, California Institute of Technology; Pasadena, California, United States
| | - Nayla Abney
- Division of Chemistry and Chemical Engineering, California Institute of Technology; Pasadena, California, United States
- Present address: Department of Bioengineering, Stanford University; Stanford, California, United States
| | - Frances H. Arnold
- Division of Chemistry and Chemical Engineering, California Institute of Technology; Pasadena, California, United States
- Division of Biology and Bioengineering, California Institute of Technology; Pasadena, California, United States
| |
Collapse
|
11
|
Cho Y, Tsuchiya S, Omura T, Koike K, Konoki K, Oshima Y, Yotsu-Yamashita M. Metabolic inhibitor induces dynamic changes in saxitoxin biosynthesis and metabolism in the dinoflagellate Alexandrium pacificum (Group IV) under in vivo labeling condition. HARMFUL ALGAE 2023; 122:102372. [PMID: 36754461 DOI: 10.1016/j.hal.2022.102372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Revised: 12/14/2022] [Accepted: 12/19/2022] [Indexed: 06/18/2023]
Abstract
In paralytic shellfish toxin-producing dinoflagellates, intracellular levels of saxitoxin and its analogues (STXs) are controlled by a balance between degradation and biosynthesis in response to marine environmental fluctuations and stresses. The purpose of this study was to demonstrate the utility of statistical analysis of in vivo labeling data for the dynamic analysis of variations in toxin production under stress. A toxic strain of the dinoflagellate Alexandrium pacificum (Group IV) was cultured in colchicine-containing 15N-labeled sodium nitrate-medium and metabolite levels were analyzed over time by liquid chromatography-mass spectrometry. Quantitative values of all isotopomers of precursor amino acids, biosynthetic intermediates, and major STXs were subjected to statistical analysis. The decrease of the nitrogen incorporation rates for all compounds suggested that colchicine decreased nitrate assimilation upstream of glutamate biosynthesis. In colchicine-treated cultures, the per-cell content of total STX analogues did not change significantly over time; however, the production rate of each pathway varied greatly. De novo STX biosynthesis was decreased by colchicine until Day 3, while the salvage pathway was not. Subsequently, biosynthesis by both pathways was enhanced. This analysis of dynamic metabolism provides new insights into the complex mechanisms regulating STX metabolism in dinoflagellates.
Collapse
Affiliation(s)
- Yuko Cho
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan.
| | - Shigeki Tsuchiya
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Takuo Omura
- Laboratory of Aquatic Science Consultant Co., LTD. 2-30-17, Higashikamata, Ota-ku, Tokyo 144-0031, Japan
| | - Kazuhiko Koike
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8528, Japan
| | - Keiichi Konoki
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Yasukatsu Oshima
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Mari Yotsu-Yamashita
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| |
Collapse
|
12
|
Rogers MS, Gordon AM, Rappe TM, Goodpaster JD, Lipscomb JD. Contrasting Mechanisms of Aromatic and Aryl-Methyl Substituent Hydroxylation by the Rieske Monooxygenase Salicylate 5-Hydroxylase. Biochemistry 2023; 62:507-523. [PMID: 36583545 PMCID: PMC9854337 DOI: 10.1021/acs.biochem.2c00610] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The hydroxylase component (S5HH) of salicylate-5-hydroxylase catalyzes C5 ring hydroxylation of salicylate but switches to methyl hydroxylation when a C5 methyl substituent is present. The use of 18O2 reveals that both aromatic and aryl-methyl hydroxylations result from monooxygenase chemistry. The functional unit of S5HH comprises a nonheme Fe(II) site located 12 Å across a subunit boundary from a one-electron reduced Rieske-type iron-sulfur cluster. Past studies determined that substrates bind near the Fe(II), followed by O2 binding to the iron to initiate catalysis. Stopped-flow-single-turnover reactions (STOs) demonstrated that the Rieske cluster transfers an electron to the iron site during catalysis. It is shown here that fluorine ring substituents decrease the rate constant for Rieske electron transfer, implying a prior reaction of an Fe(III)-superoxo intermediate with a substrate. We propose that the iron becomes fully oxidized in the resulting Fe(III)-peroxo-substrate-radical intermediate, allowing Rieske electron transfer to occur. STO using 5-CD3-salicylate-d8 occurs with an inverse kinetic isotope effect (KIE). In contrast, STO of a 1:1 mixture of unlabeled and 5-CD3-salicylate-d8 yields a normal product isotope effect. It is proposed that aromatic and aryl-methyl hydroxylation reactions both begin with the Fe(III)-superoxo reaction with a ring carbon, yielding the inverse KIE due to sp2 → sp3 carbon hybridization. After Rieske electron transfer, the resulting Fe(III)-peroxo-salicylate intermediate can continue to aromatic hydroxylation, whereas the equivalent aryl-methyl intermediate formation must be reversible to allow the substrate exchange necessary to yield a normal product isotope effect. The resulting Fe(III)-(hydro)peroxo intermediate may be reactive or evolve through a high-valent iron intermediate to complete the aryl-methyl hydroxylation.
Collapse
Affiliation(s)
- Melanie S. Rogers
- Department of Biochemistry, Molecular Biology, and Biophysics and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Adrian M. Gordon
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Todd M. Rappe
- Minnesota NMR Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Jason D. Goodpaster
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - John D. Lipscomb
- Department of Biochemistry, Molecular Biology, and Biophysics and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
| |
Collapse
|
13
|
Hu WY, Li K, Weitz A, Wen A, Kim H, Murray JC, Cheng R, Chen B, Naowarojna N, Grinstaff MW, Elliott SJ, Chen JS, Liu P. Light-Driven Oxidative Demethylation Reaction Catalyzed by a Rieske-Type Non-heme Iron Enzyme Stc2. ACS Catal 2022; 12:14559-14570. [PMID: 37168530 PMCID: PMC10168674 DOI: 10.1021/acscatal.2c04232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Rieske-type non-heme iron oxygenases/oxidases catalyze a wide range of transformations. Their applications in bioremediation or biocatalysis face two key barriers: the need of expensive NAD(P)H as a reductant and a proper reductase to mediate the electron transfer from NAD(P)H to the oxygenases. To bypass the need of both the reductase and NAD(P)H, using Rieske-type oxygenase (Stc2) catalyzed oxidative demethylation as the model system, we report Stc2 photocatalysis using eosin Y/sulfite as the photosensitizer/sacrificial reagent pair. In a flow-chemistry setting to separate the photo-reduction half-reaction and oxidation half-reaction, Stc2 photo-biocatalysis outperforms the Stc2-NAD(P)H-reductase (GbcB) system. In addition, in a few other selected Rieske enzymes (NdmA, CntA, and GbcA), and a flavin-dependent enzyme (iodotyrosine deiodinase, IYD), the eosin Y/sodium sulfite photo-reduction pair could also serve as the NAD(P)H-reductase surrogate to support catalysis, which implies the potential applicability of this photo-reduction system to other redox enzymes.
Collapse
Affiliation(s)
- Wei-Yao Hu
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai200240, P. R. China
- Department of Chemistry, Boston University, Boston, Massachusetts02215, United States
| | - Kelin Li
- Department of Chemistry, Boston University, Boston, Massachusetts02215, United States
| | - Andrew Weitz
- Department of Chemistry, Boston University, Boston, Massachusetts02215, United States
| | - Aiwen Wen
- Department of Chemistry, Boston University, Boston, Massachusetts02215, United States
| | - Hyomin Kim
- Department of Chemistry, Boston University, Boston, Massachusetts02215, United States
| | - Jessica C. Murray
- Department of Chemistry, Boston University, Boston, Massachusetts02215, United States
| | - Ronghai Cheng
- Department of Chemistry, Boston University, Boston, Massachusetts02215, United States
| | - Baixiong Chen
- Department of Chemistry, Boston University, Boston, Massachusetts02215, United States
| | - Nathchar Naowarojna
- Department of Chemistry, Boston University, Boston, Massachusetts02215, United States
| | - Mark W. Grinstaff
- Department of Chemistry, Boston University, Boston, Massachusetts02215, United States
| | - Sean J. Elliott
- Department of Chemistry, Boston University, Boston, Massachusetts02215, United States
| | - Jie-Sheng Chen
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai200240, P. R. China
| | - Pinghua Liu
- Department of Chemistry, Boston University, Boston, Massachusetts02215, United States
| |
Collapse
|
14
|
Mary L, Quere J, Latimier M, Rovillon GA, Hégaret H, Réveillon D, Le Gac M. Genetic association of toxin production in the dinoflagellate Alexandrium minutum. Microb Genom 2022; 8:mgen000879. [PMID: 36326655 PMCID: PMC9836089 DOI: 10.1099/mgen.0.000879] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 07/25/2022] [Indexed: 11/06/2022] Open
Abstract
Dinoflagellates of the genus Alexandrium are responsible for harmful algal blooms and produce paralytic shellfish toxins (PSTs). Their very large and complex genomes make it challenging to identify the genes responsible for toxin synthesis. A family-based genomic association study was developed to determine the inheritance of toxin production in Alexandrium minutum and identify genomic regions linked to this production. We show that the ability to produce toxins is inheritable in a Mendelian way, while the heritability of the toxin profile is more complex. We developed the first dinoflagellate genetic linkage map. Using this map, several major results were obtained: 1. A genomic region related to the ability to produce toxins was identified. 2. This region does not contain any polymorphic sxt genes, known to be involved in toxin production in cyanobacteria. 3. The sxt genes, known to be present in a single cluster in cyanobacteria, are scattered on different linkage groups in A. minutum. 4. The expression of two sxt genes not assigned to any linkage group, sxtI and sxtG, may be regulated by the genomic region related to the ability to produce toxins. Our results provide new insights into the organization of toxicity-related genes in A. minutum, suggesting a dissociated genetic mechanism for the production of the different analogues and the ability to produce toxins. However, most of the newly identified genes remain unannotated. This study therefore proposes new candidate genes to be further explored to understand how dinoflagellates synthesize their toxins.
Collapse
Affiliation(s)
- Lou Mary
- Ifremer, DYNECO PELAGOS, 29280 Plouzané, France
- Ifremer, PHYTOX, Laboratoire METALG, F-44000 Nantes, France
- Laboratoire des Sciences de l’Environnement Marin (LEMAR), UMR 6539 CNRS UBO IRD IFREMER - Institut Universitaire Européen de la Mer, 29280 Plouzané, France
| | | | | | | | - Hélène Hégaret
- Laboratoire des Sciences de l’Environnement Marin (LEMAR), UMR 6539 CNRS UBO IRD IFREMER - Institut Universitaire Européen de la Mer, 29280 Plouzané, France
| | | | | |
Collapse
|
15
|
Liu J, Knapp M, Jo M, Dill Z, Bridwell-Rabb J. Rieske Oxygenase Catalyzed C-H Bond Functionalization Reactions in Chlorophyll b Biosynthesis. ACS CENTRAL SCIENCE 2022; 8:1393-1403. [PMID: 36313167 PMCID: PMC9615114 DOI: 10.1021/acscentsci.2c00058] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Indexed: 05/03/2023]
Abstract
Rieske oxygenases perform precise C-H bond functionalization reactions in anabolic and catabolic pathways. These reactions are typically characterized as monooxygenation or dioxygenation reactions, but other divergent reactions are also catalyzed by Rieske oxygenases. Chlorophyll(ide) a oxygenase (CAO), for example is proposed to catalyze two monooxygenation reactions to transform a methyl-group into the formyl-group of Chlorophyll b. This formyl group, like the formyl groups found in other chlorophyll pigments, tunes the absorption spectra of chlorophyllb and supports the ability of several photosynthetic organisms to adapt to environmental light. Despite the importance of this reaction, CAO has never been studied in vitro with purified protein, leaving many open questions regarding whether CAO can facilitate both oxygenation reactions using just the Rieske oxygenase machinery. In this study, we demonstrated that four CAO homologues in partnership with a non-native reductase convert a Chlorophyll a precursor, chlorophyllidea, into chlorophyllideb in vitro. Analysis of this reaction confirmed the existence of the proposed intermediate, highlighted the stereospecificity of the reaction, and revealed the potential of CAO as a tool for synthesizing custom-tuned natural and unnatural chlorophyll pigments. This work thus adds to our fundamental understanding of chlorophyll biosynthesis and Rieske oxygenase chemistry.
Collapse
|
16
|
Pati SG, Bopp CE, Kohler HPE, Hofstetter TB. Substrate-Specific Coupling of O 2 Activation to Hydroxylations of Aromatic Compounds by Rieske Non-heme Iron Dioxygenases. ACS Catal 2022; 12:6444-6456. [PMID: 35692249 PMCID: PMC9171724 DOI: 10.1021/acscatal.2c00383] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 04/09/2022] [Indexed: 02/07/2023]
Abstract
![]()
Rieske dioxygenases
catalyze the initial steps in the hydroxylation
of aromatic compounds and are critical for the metabolism of xenobiotic
substances. Because substrates do not bind to the mononuclear non-heme
FeII center, elementary steps leading to O2 activation
and substrate hydroxylation are difficult to delineate, thus making
it challenging to rationalize divergent observations on enzyme mechanisms,
reactivity, and substrate specificity. Here, we show for nitrobenzene
dioxygenase, a Rieske dioxygenase capable of transforming nitroarenes
to nitrite and substituted catechols, that unproductive O2 activation with the release of the unreacted substrate and reactive
oxygen species represents an important path in the catalytic cycle.
Through correlation of O2 uncoupling for a series of substituted
nitroaromatic compounds with 18O and 13C kinetic
isotope effects of dissolved O2 and aromatic substrates,
respectively, we show that O2 uncoupling occurs after the
rate-limiting formation of FeIII-(hydro)peroxo species
from which substrates are hydroxylated. Substituent effects on the
extent of O2 uncoupling suggest that the positioning of
the substrate in the active site rather than the susceptibility of
the substrate for attack by electrophilic oxygen species is responsible
for unproductive O2 uncoupling. The proposed catalytic
cycle provides a mechanistic basis for assessing the very different
efficiencies of substrate hydroxylation vs unproductive O2 activation and generation of reactive oxygen species in reactions
catalyzed by Rieske dioxygenases.
Collapse
Affiliation(s)
- Sarah G. Pati
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, 8092 Zürich, Switzerland
| | - Charlotte E. Bopp
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, 8092 Zürich, Switzerland
| | - Hans-Peter E. Kohler
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Thomas B. Hofstetter
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, 8092 Zürich, Switzerland
| |
Collapse
|
17
|
First Identification of 12β-Deoxygonyautoxin 5 (12α-Gonyautoxinol 5) in the Cyanobacterium Dolichospermum circinale (TA04) and 12β-Deoxysaxitoxin (12α-Saxitoxinol) in D. circinale (TA04) and the Dinoflagellate Alexandrium pacificum (Group IV) (120518KureAC). Mar Drugs 2022; 20:md20030166. [PMID: 35323466 PMCID: PMC8954441 DOI: 10.3390/md20030166] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 02/20/2022] [Accepted: 02/22/2022] [Indexed: 02/01/2023] Open
Abstract
Saxitoxin and its analogues, paralytic shellfish toxins (PSTs), are potent and specific voltage-gated sodium channel blockers. These toxins are produced by some species of freshwater cyanobacteria and marine dinoflagellates. We previously identified several biosynthetic intermediates of PSTs, as well as new analogues, from such organisms and proposed the biosynthetic and metabolic pathways of PSTs. In this study, 12β-deoxygonyautoxin 5 (12α-gonyautoxinol 5 = gonyautoxin 5-12(R)-ol) was identified in the freshwater cyanobacterium, Dolichospermum circinale (TA04), and 12β-deoxysaxitoxin (12α-saxitoxinol = saxitoxin-12(R)-ol) was identified in the same cyanobacterium and in the marine dinoflagellate Alexandrium pacificum (Group IV) (120518KureAC) for the first time from natural sources. The authentic standards of these compounds and 12α-deoxygonyautoxin 5 (12β-gonyautoxinol 5 = gonyautoxin 5-12(S)-ol) were prepared by chemical derivatization from the major PSTs, C1/C2, produced in D. circinale (TA04). These standards were used to identify the deoxy analogues by comparing the retention times and MS/MS spectra using high-resolution LC-MS/MS. Biosynthetic or metabolic pathways for these analogues have also been proposed based on their structures. The identification of these compounds supports the α-oriented stereoselective oxidation at C12 in the biosynthetic pathway towards PSTs.
Collapse
|
18
|
Abstract
This review deals with the synthesis of naturally occurring alkaloids containing partially or completely saturated pyrimidine nuclei. The interest in these compounds is associated with their structural diversity, high biological activity and toxicity. The review is divided into four parts, each of which describes a number of synthetic methodologies toward structurally different naturally occurring alkaloids containing saturated cyclic six-membered amidine, guanidine, aminal and urea (thiourea) moieties, respectively. The development of various synthetic strategies for the preparation of these compounds has remarkably increased during the past few decades. This is primarily due to the fact that some of these compounds are isolated only in limited quantities, which makes it practically impossible to study their full structural characteristics and biological activity.
Collapse
|
19
|
Design principles for site-selective hydroxylation by a Rieske oxygenase. Nat Commun 2022; 13:255. [PMID: 35017498 PMCID: PMC8752792 DOI: 10.1038/s41467-021-27822-3] [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: 08/07/2021] [Accepted: 12/15/2021] [Indexed: 01/12/2023] Open
Abstract
Rieske oxygenases exploit the reactivity of iron to perform chemically challenging C–H bond functionalization reactions. Thus far, only a handful of Rieske oxygenases have been structurally characterized and remarkably little information exists regarding how these enzymes use a common architecture and set of metallocenters to facilitate a diverse range of reactions. Herein, we detail how two Rieske oxygenases SxtT and GxtA use different protein regions to influence the site-selectivity of their catalyzed monohydroxylation reactions. We present high resolution crystal structures of SxtT and GxtA with the native β-saxitoxinol and saxitoxin substrates bound in addition to a Xenon-pressurized structure of GxtA that reveals the location of a substrate access tunnel to the active site. Ultimately, this structural information allowed for the identification of six residues distributed between three regions of SxtT that together control the selectivity of the C–H hydroxylation event. Substitution of these residues produces a SxtT variant that is fully adapted to exhibit the non-native site-selectivity and substrate scope of GxtA. Importantly, we also found that these selectivity regions are conserved in other structurally characterized Rieske oxygenases, providing a framework for predictively repurposing and manipulating Rieske oxygenases as biocatalysts. SxtT and GxtA are Rieske oxygenases that are involved in paralytic shellfish toxin biosynthesis and catalyze monohydroxylation reactions at different positions on the toxin scaffold. Here, the authors present crystal structures of SxtT and GxtA with the native substrates β-saxitoxinol and saxitoxin as well as a Xenon-pressurized structure of GxtA, which reveal a substrate access tunnel to the active site. Through structure-based mutagenesis studies the authors identify six residues in three different protein regions that determine the substrate specificity and site selectivity of SxtT and GxtA. These findings will aid the rational engineering of other Rieske oxygenases.
Collapse
|
20
|
Costas M. Site and Enantioselective Aliphatic C-H Oxidation with Bioinspired Chiral Complexes. CHEM REC 2021; 21:4000-4014. [PMID: 34609780 DOI: 10.1002/tcr.202100227] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/17/2021] [Accepted: 09/17/2021] [Indexed: 12/12/2022]
Abstract
Selective oxidation of aliphatic C-H bonds stands as an unsolved problem in organic synthesis, with the potential to offer novel paths for preparing molecules of biological interest. The quest for reagents that can perform this class of reactions finds oxygenases and their mechanisms of action as inspiration motifs. Among the numerous families of synthetic catalysts that have been explored, complexes with linear tetraazadentate ligands combining two aliphatic amines and two aromatic amine heterocycles display a structural versatility proven instrumental in the design of C-H oxidation reactions showing site and enantioselectivities, not accessible by conventional oxidants. This manuscript makes a review of recent advances in the field.
Collapse
Affiliation(s)
- Miquel Costas
- Department of Chemistry and Institut de Química Computacional I Catàlisi (IQCC), Universitat de Girona Facultat de Ciències, Campus de Montilivi, 17003, Girona, Spain
| |
Collapse
|
21
|
Numano S, Kudo Y, Cho Y, Konoki K, Kaga Y, Nagasawa K, Yotsu-Yamashita M. Two new skeletal analogues of saxitoxin found in the scallop, Patinopecten yessoensis, as possible metabolites of paralytic shellfish toxins. CHEMOSPHERE 2021; 278:130224. [PMID: 33813339 DOI: 10.1016/j.chemosphere.2021.130224] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 03/09/2021] [Accepted: 03/10/2021] [Indexed: 06/12/2023]
Abstract
The scallop, Patinopecten yessoensis, was screened for new saxitoxin analogues to study the metabolism of paralytic shellfish toxins (PSTs), and this resulted in the discovery of two new analogues: M5-hemiaminal (HA) and M6-HA. M5-HA was isolated and its structure was determined by using NMR spectroscopy. It contains hydrogen at C-4 with opposite stereochemistry to that in saxitoxin, and a hemiaminal was formed between 9-NH2 and the hydrated ketone at C-12 in α-orientation. This is the first reported structural feature in a natural saxitoxin analogue, whereas the same ring system has previously been reported in a synthetic saxitoxin analogue, FD-saxitoxin. Acid hydrolysis of the carbamoyl N-sulfate in M5-HA produced M6-HA which was also identified in P. yessoensis by using LC-MSMS. M5-HA was not synthetically produced from M1 (11-hydroxy gonyautoxin-5) and M3 (11,11-dihydroxy gonyautoxin-5) through incubation in aqueous buffers. Furthermore, PSTs in the hepatopancreas of P. yessoensis, cultured in a bay located in northeastern Japan, were chronologically analyzed in 2018. The highest concentrations of M1/M3/M5-HA were observed two weeks after C-toxins had reached their highest concentrations, which provides evidence that M1/M3/M5-HA are metabolites of C-toxins. The voltage-gated sodium channel blockage activity of M6-HA was not detected at the concentration of 140 nM by using the Neuro-2A veratridine/ouabain assay.
Collapse
Affiliation(s)
- Satoshi Numano
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi, 980-8572, Japan; Iwate Prefectural Research Institute for Environmental Sciences and Public Health, 1-11-16 Kita-Iioka, Morioka, Iwate, 020-0857, Japan
| | - Yuta Kudo
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi, 980-8572, Japan; Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi, 980-8578, Japan
| | - Yuko Cho
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi, 980-8572, Japan
| | - Keiichi Konoki
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi, 980-8572, Japan
| | - Yoshimasa Kaga
- Iwate Prefectural Inland Fisheries Technology Center, Yoriki, Matsuo, Iwate, 028-7302, Japan
| | - Kazuo Nagasawa
- Department of Biotechnology and Life Science, Faculty of Technology, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Mari Yotsu-Yamashita
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi, 980-8572, Japan.
| |
Collapse
|
22
|
Pyser J, Chakrabarty S, Romero EO, Narayan ARH. State-of-the-Art Biocatalysis. ACS CENTRAL SCIENCE 2021; 7:1105-1116. [PMID: 34345663 PMCID: PMC8323117 DOI: 10.1021/acscentsci.1c00273] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Indexed: 05/03/2023]
Abstract
The use of enzyme-mediated reactions has transcended ancient food production to the laboratory synthesis of complex molecules. This evolution has been accelerated by developments in sequencing and DNA synthesis technology, bioinformatic and protein engineering tools, and the increasingly interdisciplinary nature of scientific research. Biocatalysis has become an indispensable tool applied in academic and industrial spheres, enabling synthetic strategies that leverage the exquisite selectivity of enzymes to access target molecules. In this Outlook, we outline the technological advances that have led to the field's current state. Integration of biocatalysis into mainstream synthetic chemistry hinges on increased access to well-characterized enzymes and the permeation of biocatalysis into retrosynthetic logic. Ultimately, we anticipate that biocatalysis is poised to enable the synthesis of increasingly complex molecules at new levels of efficiency and throughput.
Collapse
Affiliation(s)
- Joshua
B. Pyser
- Department
of Chemistry, Life Sciences Institute, and Program in Chemical Biology, University of Michigan, , 210 Washtenaw Avenue, Ann Arbor, Michigan 48109, United
States
| | - Suman Chakrabarty
- Department
of Chemistry, Life Sciences Institute, and Program in Chemical Biology, University of Michigan, , 210 Washtenaw Avenue, Ann Arbor, Michigan 48109, United
States
| | - Evan O. Romero
- Department
of Chemistry, Life Sciences Institute, and Program in Chemical Biology, University of Michigan, , 210 Washtenaw Avenue, Ann Arbor, Michigan 48109, United
States
| | - Alison R. H. Narayan
- Department
of Chemistry, Life Sciences Institute, and Program in Chemical Biology, University of Michigan, , 210 Washtenaw Avenue, Ann Arbor, Michigan 48109, United
States
| |
Collapse
|
23
|
Romero E, Jones BS, Hogg BN, Rué Casamajo A, Hayes MA, Flitsch SL, Turner NJ, Schnepel C. Enzymkatalysierte späte Modifizierungen: Besser spät als nie. ANGEWANDTE CHEMIE (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 133:16962-16993. [PMID: 38505660 PMCID: PMC10946893 DOI: 10.1002/ange.202014931] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 01/15/2021] [Indexed: 03/21/2024]
Abstract
AbstractDie Enzymkatalyse gewinnt zunehmend an Bedeutung in der Synthesechemie. Die durch Bioinformatik und Enzym‐Engineering stetig wachsende Zahl von Biokatalysatoren eröffnet eine große Vielfalt selektiver Reaktionen. Insbesondere für späte Funktionalisierungsreaktionen ist die Biokatalyse ein geeignetes Werkzeug, das oftmals der konventionellen De‐novo‐Synthese überlegen ist. Enzyme haben sich als nützlich erwiesen, um funktionelle Gruppen direkt in komplexe Molekülgerüste einzuführen sowie für die rasche Diversifizierung von Substanzbibliotheken. Biokatalytische Oxyfunktionalisierungen, Halogenierungen, Methylierungen, Reduktionen und Amidierungen sind von besonderem Interesse, da diese Strukturmotive häufig in Pharmazeutika vertreten sind. Dieser Aufsatz gibt einen Überblick über die Stärken und Schwächen der enzymkatalysierten späten Modifizierungen durch native und optimierte Enzyme in der Synthesechemie. Ebenso werden wichtige Beispiele in der Wirkstoffentwicklung hervorgehoben.
Collapse
Affiliation(s)
- Elvira Romero
- Compound Synthesis and ManagementDiscovery Sciences, BioPharmaceuticals R&DAstraZenecaGötheborgSchweden
| | - Bethan S. Jones
- School of ChemistryThe University of ManchesterManchester Institute of Biotechnology131 Princess StreetManchesterM1 7DNVereinigtes Königreich
| | - Bethany N. Hogg
- School of ChemistryThe University of ManchesterManchester Institute of Biotechnology131 Princess StreetManchesterM1 7DNVereinigtes Königreich
| | - Arnau Rué Casamajo
- School of ChemistryThe University of ManchesterManchester Institute of Biotechnology131 Princess StreetManchesterM1 7DNVereinigtes Königreich
| | - Martin A. Hayes
- Compound Synthesis and ManagementDiscovery Sciences, BioPharmaceuticals R&DAstraZenecaGötheborgSchweden
| | - Sabine L. Flitsch
- School of ChemistryThe University of ManchesterManchester Institute of Biotechnology131 Princess StreetManchesterM1 7DNVereinigtes Königreich
| | - Nicholas J. Turner
- School of ChemistryThe University of ManchesterManchester Institute of Biotechnology131 Princess StreetManchesterM1 7DNVereinigtes Königreich
| | - Christian Schnepel
- School of ChemistryThe University of ManchesterManchester Institute of Biotechnology131 Princess StreetManchesterM1 7DNVereinigtes Königreich
| |
Collapse
|
24
|
Romero E, Jones BS, Hogg BN, Rué Casamajo A, Hayes MA, Flitsch SL, Turner NJ, Schnepel C. Enzymatic Late-Stage Modifications: Better Late Than Never. Angew Chem Int Ed Engl 2021; 60:16824-16855. [PMID: 33453143 PMCID: PMC8359417 DOI: 10.1002/anie.202014931] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 01/15/2021] [Indexed: 12/16/2022]
Abstract
Enzyme catalysis is gaining increasing importance in synthetic chemistry. Nowadays, the growing number of biocatalysts accessible by means of bioinformatics and enzyme engineering opens up an immense variety of selective reactions. Biocatalysis especially provides excellent opportunities for late-stage modification often superior to conventional de novo synthesis. Enzymes have proven to be useful for direct introduction of functional groups into complex scaffolds, as well as for rapid diversification of compound libraries. Particularly important and highly topical are enzyme-catalysed oxyfunctionalisations, halogenations, methylations, reductions, and amide bond formations due to the high prevalence of these motifs in pharmaceuticals. This Review gives an overview of the strengths and limitations of enzymatic late-stage modifications using native and engineered enzymes in synthesis while focusing on important examples in drug development.
Collapse
Affiliation(s)
- Elvira Romero
- Compound Synthesis and ManagementDiscovery Sciences, BioPharmaceuticals R&DAstraZenecaGothenburgSweden
| | - Bethan S. Jones
- School of ChemistryThe University of ManchesterManchester Institute of Biotechnology131 Princess StreetManchesterM1 7DNUnited Kingdom
| | - Bethany N. Hogg
- School of ChemistryThe University of ManchesterManchester Institute of Biotechnology131 Princess StreetManchesterM1 7DNUnited Kingdom
| | - Arnau Rué Casamajo
- School of ChemistryThe University of ManchesterManchester Institute of Biotechnology131 Princess StreetManchesterM1 7DNUnited Kingdom
| | - Martin A. Hayes
- Compound Synthesis and ManagementDiscovery Sciences, BioPharmaceuticals R&DAstraZenecaGothenburgSweden
| | - Sabine L. Flitsch
- School of ChemistryThe University of ManchesterManchester Institute of Biotechnology131 Princess StreetManchesterM1 7DNUnited Kingdom
| | - Nicholas J. Turner
- School of ChemistryThe University of ManchesterManchester Institute of Biotechnology131 Princess StreetManchesterM1 7DNUnited Kingdom
| | - Christian Schnepel
- School of ChemistryThe University of ManchesterManchester Institute of Biotechnology131 Princess StreetManchesterM1 7DNUnited Kingdom
| |
Collapse
|
25
|
Affiliation(s)
- Judith Münch
- Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120, Halle, Saale, Germany
| | - Pascal Püllmann
- Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120, Halle, Saale, Germany
| | - Wuyuan Zhang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West seventh Avenue, Tianjin 300308, China
- National Technology Innovation Center of Synthetic Biology, 32 West seventh Avenue, Tianjin 300308, China
| | - Martin J. Weissenborn
- Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120, Halle, Saale, Germany
- Institute of Chemistry, MartinLuther-University Halle-Wittenberg, Kurt-Mothes-Strasse 2, 06120, Halle, Saale, Germany
| |
Collapse
|
26
|
Li B, Steindel P, Haddad N, Elliott SJ. Maximizing (Electro)catalytic CO 2 Reduction with a Ferredoxin-Based Reduction Potential Gradient. ACS Catal 2021. [DOI: 10.1021/acscatal.1c00092] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Bin Li
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Phillip Steindel
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Narmien Haddad
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Sean J. Elliott
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| |
Collapse
|
27
|
Chakrabarty S, Romero EO, Pyser JB, Yazarians JA, Narayan ARH. Chemoenzymatic Total Synthesis of Natural Products. Acc Chem Res 2021; 54:1374-1384. [PMID: 33600149 PMCID: PMC8210581 DOI: 10.1021/acs.accounts.0c00810] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The total synthesis of structurally complex natural products has challenged and inspired generations of chemists and remains an exciting area of active research. Despite their history as privileged bioactivity-rich scaffolds, the use of natural products in drug discovery has waned. This shift is driven by their relatively low abundance hindering isolation from natural sources and the challenges presented by their synthesis. Recent developments in biocatalysis have resulted in the application of enzymes for the construction of complex molecules. From the inception of the Narayan lab in 2015, we have focused on harnessing the exquisite selectivity of enzymes alongside contemporary small molecule-based approaches to enable concise chemoenzymatic routes to natural products.We have focused on enzymes from various families that perform selective oxidation reactions. For example, we have targeted xyloketal natural products through a strategy that relies on a chemo- and site-selective biocatalytic hydroxylation. Members of the xyloketal family are characterized by polycyclic ketal cores and demonstrate potent neurological activity. We envisioned assembling a representative xyloketal natural product (xyloketal D) involving a biocatalytically generated ortho-quinone methide intermediate. The non-heme iron (NHI) dependent monooxygenase ClaD was used to perform the benzylic hydroxylation of a resorcinol precursor, the product of which can undergo spontaneous loss of water to form an ortho-quinone methide under mild conditions. This intermediate was trapped using a chiral dienophile to complete the total synthesis of xyloketal D.A second class of biocatalytic oxidation that we have employed in synthesis is the hydroxylative dearomatization of resorcinol compounds using flavin-dependent monooxygenases (FDMOs). We anticipated that the catalyst-controlled site- and stereoselectivity of FDMOs would enable the total synthesis of azaphilone natural products. Azaphilones are bioactive compounds characterized by a pyranoquinone bicyclic core and a fully substituted chiral carbon atom. We leveraged the stereodivergent reactivity of FDMOs AzaH and AfoD to achieve the enantioselective synthesis of trichoflectin enantiomers, deflectin 1a, and lunatoic acid. We also leveraged FDMOs to construct tropolone and sorbicillinoid natural products. Tropolones are a structurally diverse class of bioactive molecules characterized by an aromatic cycloheptatriene core bearing an α-hydroxyketone moiety. We developed a two-step biocatalytic cascade to the tropolone natural product stipitatic aldehyde using the FDMO TropB and a NHI monooxygenase TropC. The FDMO SorbC obtained from the sorbicillin biosynthetic pathway was used in the concise total synthesis of a urea sorbicillinoid natural product.Our long-standing interest in using enzymes to carry out C-H hydroxylation reactions has also been channeled for the late-stage diversification of complex scaffolds. For example, we have used Rieske oxygenases to hydroxylate the tricyclic core common to paralytic shellfish toxins. The systemic toxicity of these compounds can be reduced by adding hydroxyl and sulfate groups, which improves their properties and potential as therapeutic agents. The enzymes SxtT, GxtA, SxtN, and SxtSUL were used to carry out selective C-H hydroxylation and O-sulfation in saxitoxin and related structures. We conclude this Account with a discussion of existing challenges in biocatalysis and ways we can currently address them.
Collapse
Affiliation(s)
- Suman Chakrabarty
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Evan O. Romero
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Joshua B. Pyser
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Jessica A. Yazarians
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Alison R. H. Narayan
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| |
Collapse
|
28
|
Cho Y, Hidema S, Omura T, Koike K, Koike K, Oikawa H, Konoki K, Oshima Y, Yotsu-Yamashita M. SxtA localizes to chloroplasts and changes to its 3'UTR may reduce toxin biosynthesis in non-toxic Alexandrium catenella (Group I) ✰. HARMFUL ALGAE 2021; 101:101972. [PMID: 33526188 DOI: 10.1016/j.hal.2020.101972] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 12/14/2020] [Accepted: 12/19/2020] [Indexed: 06/12/2023]
Abstract
SxtA is the enzyme that catalyses the first step of saxitoxin biosynthesis. We developed an immunofluorescent method to detect SxtA using antibodies against SxtA peptides. Confocal microscopy revealed the presence of abundant, sub-cellularly localized signal in cells of toxic species and its absence in non-toxic species. Co-localization of SxtA with Rubisco II and ultra-structural observation by transmission electron microscopy strongly suggested the association of SxtA with chloroplasts. We also characterized a non-toxic sub-clone of Alexandrium catenella (Group I) to elucidate the mutation responsible for its loss of toxicity. Although sxtA4 gene copy number was indistinguishable in toxic and non-toxic sub-clones, mRNA and protein expression were significantly reduced in the non-toxic sub-clone and we uncovered sequence variation at the 3' untranslated region (3'UTR) of sxtA4 mRNA. We propose that differences in the sxtA4 mRNA 3'UTR lead to down-regulation of STX biosynthesis post-transcriptionally, thereby explaining the differences in toxicity amongst different A. catenella (Group I) sub-clones.
Collapse
Affiliation(s)
- Yuko Cho
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan.
| | - Shizu Hidema
- Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University, 1 Hikariga-oka, Fukushima 960-1295, Japan
| | - Takuo Omura
- Laboratory of Aquatic Science Consultant Co., Ltd. 2-30-17, Higashikamata, Ota-ku, Tokyo 144-0031, Japan
| | - Kazuhiko Koike
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8528, Japan
| | - Kanae Koike
- Natural Science Center for Basic Research and Development, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8528, Japan
| | - Hiroshi Oikawa
- Japan Fisheries Research and Education Agency, Fisheries Technology Institute, 2-12-4 Fukuura, Kanazawa, Yokohama, Kanagawa 236-8648, Japan
| | - Keiichi Konoki
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Yasukatsu Oshima
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Mari Yotsu-Yamashita
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| |
Collapse
|
29
|
Renata H. Exploration of Iron- and a-Ketoglutarate-Dependent Dioxygenases as Practical Biocatalysts in Natural Product Synthesis. Synlett 2021; 32:775-784. [PMID: 34413574 PMCID: PMC8372184 DOI: 10.1055/s-0040-1707320] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Catalytic C─H oxidation is a powerful transformation with enormous promise to streamline access to complex molecules. In recent years, biocatalytic C─H oxidation strategies have received tremendous attention due to their potential to address unmet regio- and stereoselectivity challenges that are often encountered with the use of small-molecule-based catalysts. This Account provides an overview of recent contributions from our laboratory in this area, specifically in the use of iron- and α-ketoglutarate-dependent dioxygenases in the chemoenzymatic synthesis of complex natural products.
Collapse
Affiliation(s)
- Hans Renata
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL, 33458, USA
| |
Collapse
|
30
|
Biosynthesis of marine toxins. Curr Opin Chem Biol 2020; 59:119-129. [DOI: 10.1016/j.cbpa.2020.06.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/21/2020] [Accepted: 06/23/2020] [Indexed: 12/18/2022]
|
31
|
Chakrabarty S, Wang Y, Perkins JC, Narayan ARH. Scalable biocatalytic C-H oxyfunctionalization reactions. Chem Soc Rev 2020; 49:8137-8155. [PMID: 32701110 PMCID: PMC8177087 DOI: 10.1039/d0cs00440e] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Catalytic C-H oxyfunctionalization reactions have garnered significant attention in recent years with their ability to streamline synthetic routes toward complex molecules. Consequently, there have been significant strides in the design and development of catalysts that enable diversification through C-H functionalization reactions. Enzymatic C-H oxygenation reactions are often complementary to small molecule based synthetic approaches, providing a powerful tool when deployable on preparative-scale. This review highlights key advances in scalable biocatalytic C-H oxyfunctionalization reactions developed within the past decade.
Collapse
Affiliation(s)
- Suman Chakrabarty
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA.
| | | | | | | |
Collapse
|
32
|
Berlinck RGS, Bernardi DI, Fill T, Fernandes AAG, Jurberg ID. The chemistry and biology of guanidine secondary metabolites. Nat Prod Rep 2020; 38:586-667. [PMID: 33021301 DOI: 10.1039/d0np00051e] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Covering: 2017-2019Guanidine natural products isolated from microorganisms, marine invertebrates and terrestrial plants, amphibians and spiders, represented by non-ribosomal peptides, guanidine-bearing polyketides, alkaloids, terpenoids and shikimic acid derived, are the subject of this review. The topics include the discovery of new metabolites, total synthesis of natural guanidine compounds, biological activity and mechanism-of-action, biosynthesis and ecological functions.
Collapse
Affiliation(s)
- Roberto G S Berlinck
- Instituto de Química de São Carlos, Universidade de São Paulo, CP 780, CEP 13560-970, São Carlos, SP, Brazil.
| | | | | | | | | |
Collapse
|
33
|
Structural basis for divergent C-H hydroxylation selectivity in two Rieske oxygenases. Nat Commun 2020; 11:2991. [PMID: 32532989 PMCID: PMC7293229 DOI: 10.1038/s41467-020-16729-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 05/15/2020] [Indexed: 12/05/2022] Open
Abstract
Biocatalysts that perform C–H hydroxylation exhibit exceptional substrate specificity and site-selectivity, often through the use of high valent oxidants to activate these inert bonds. Rieske oxygenases are examples of enzymes with the ability to perform precise mono- or dioxygenation reactions on a variety of substrates. Understanding the structural features of Rieske oxygenases responsible for control over selectivity is essential to enable the development of this class of enzymes for biocatalytic applications. Decades of research has illuminated the critical features common to Rieske oxygenases, however, structural information for enzymes that functionalize diverse scaffolds is limited. Here, we report the structures of two Rieske monooxygenases involved in the biosynthesis of paralytic shellfish toxins (PSTs), SxtT and GxtA, adding to the short list of structurally characterized Rieske oxygenases. Based on these structures, substrate-bound structures, and mutagenesis experiments, we implicate specific residues in substrate positioning and the divergent reaction selectivity observed in these two enzymes. Rieske oxygenases are iron-dependent enzymes that catalyse C–H mono- and dihydroxylation reactions. Here, the authors characterise two cyanobacterial Rieske oxygenases, SxtT and GxtA that are involved in the biosynthesis of paralytic shellfish toxins and determine their substrate free and saxitoxin analog-bound crystal structures and by using mutagenesis experiments identify residues, which are important for substrate positioning and reaction selectivity.
Collapse
|
34
|
Raposo MIC, Gomes MTSR, Botelho MJ, Rudnitskaya A. Paralytic Shellfish Toxins (PST)-Transforming Enzymes: A Review. Toxins (Basel) 2020; 12:E344. [PMID: 32456077 PMCID: PMC7290730 DOI: 10.3390/toxins12050344] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 05/16/2020] [Accepted: 05/20/2020] [Indexed: 01/13/2023] Open
Abstract
Paralytic shellfish toxins (PSTs) are a group of toxins that cause paralytic shellfish poisoning through blockage of voltage-gated sodium channels. PSTs are produced by prokaryotic freshwater cyanobacteria and eukaryotic marine dinoflagellates. Proliferation of toxic algae species can lead to harmful algal blooms, during which seafood accumulate high levels of PSTs, posing a health threat to consumers. The existence of PST-transforming enzymes was first remarked due to the divergence of PST profiles and concentrations between contaminated bivalves and toxigenic organisms. Later, several enzymes involved in PST transformation, synthesis and elimination have been identified. The knowledge of PST-transforming enzymes is necessary for understanding the processes of toxin accumulation and depuration in mollusk bivalves. Furthermore, PST-transforming enzymes facilitate the obtainment of pure analogues of toxins as in natural sources they are present in a mixture. Pure compounds are of interest for the development of drug candidates and as analytical reference materials. PST-transforming enzymes can also be employed for the development of analytical tools for toxin detection. This review summarizes the PST-transforming enzymes identified so far in living organisms from bacteria to humans, with special emphasis on bivalves, cyanobacteria and dinoflagellates, and discusses enzymes' biological functions and potential practical applications.
Collapse
Affiliation(s)
- Mariana I. C. Raposo
- CESAM and Chemistry Department, University of Aveiro, 3810-193 Aveiro, Portugal; (M.I.C.R.); (M.T.S.R.G.)
| | - Maria Teresa S. R. Gomes
- CESAM and Chemistry Department, University of Aveiro, 3810-193 Aveiro, Portugal; (M.I.C.R.); (M.T.S.R.G.)
| | - Maria João Botelho
- Portuguese Institute for the Sea and Atmosphere, 1449-006 Lisbon, Portugal;
- Interdisciplinary Centre of Marine and Environmental Research, University of Porto, 4050-123 Porto, Portugal
| | - Alisa Rudnitskaya
- CESAM and Chemistry Department, University of Aveiro, 3810-193 Aveiro, Portugal; (M.I.C.R.); (M.T.S.R.G.)
| |
Collapse
|
35
|
Lukowski AL, Mallik L, Hinze ME, Carlson BM, Ellinwood DC, Pyser JB, Koutmos M, Narayan ARH. Substrate Promiscuity of a Paralytic Shellfish Toxin Amidinotransferase. ACS Chem Biol 2020; 15:626-631. [PMID: 32058687 DOI: 10.1021/acschembio.9b00964] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Secondary metabolites are assembled by enzymes that often perform reactions with high selectivity and specificity. Many of these enzymes also tolerate variations in substrate structure, exhibiting promiscuity that enables various applications of a given biocatalyst. However, initial enzyme characterization studies frequently do not explore beyond the native substrates. This limited assessment of substrate scope contributes to the difficulty of identifying appropriate enzymes for specific synthetic applications. Here, we report the natural function of cyanobacterial SxtG, an amidinotransferase involved in the biosynthesis of paralytic shellfish toxins, and demonstrate its ability to modify a breadth of non-native substrates. In addition, we report the first X-ray crystal structure of SxtG, which provides rationale for this enzyme's substrate scope. Taken together, these data confirm the function of SxtG and exemplify its potential utility in biocatalytic synthesis.
Collapse
|
36
|
Ganley JG, Derbyshire ER. Linking Genes to Molecules in Eukaryotic Sources: An Endeavor to Expand Our Biosynthetic Repertoire. Molecules 2020; 25:E625. [PMID: 32023950 PMCID: PMC7036892 DOI: 10.3390/molecules25030625] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 01/23/2020] [Accepted: 01/30/2020] [Indexed: 02/06/2023] Open
Abstract
The discovery of natural products continues to interest chemists and biologists for their utility in medicine as well as facilitating our understanding of signaling, pathogenesis, and evolution. Despite an attenuation in the discovery rate of new molecules, the current genomics and transcriptomics revolution has illuminated the untapped biosynthetic potential of many diverse organisms. Today, natural product discovery can be driven by biosynthetic gene cluster (BGC) analysis, which is capable of predicting enzymes that catalyze novel reactions and organisms that synthesize new chemical structures. This approach has been particularly effective in mining bacterial and fungal genomes where it has facilitated the discovery of new molecules, increased the understanding of metabolite assembly, and in some instances uncovered enzymes with intriguing synthetic utility. While relatively less is known about the biosynthetic potential of non-fungal eukaryotes, there is compelling evidence to suggest many encode biosynthetic enzymes that produce molecules with unique bioactivities. In this review, we highlight how the advances in genomics and transcriptomics have aided natural product discovery in sources from eukaryotic lineages. We summarize work that has successfully connected genes to previously identified molecules and how advancing these techniques can lead to genetics-guided discovery of novel chemical structures and reactions distributed throughout the tree of life. Ultimately, we discuss the advantage of increasing the known biosynthetic space to ease access to complex natural and non-natural small molecules.
Collapse
Affiliation(s)
- Jack G Ganley
- Department of Chemistry, Duke University, 124 Science Drive, Durham, NC 27708-0346, USA
| | - Emily R Derbyshire
- Department of Chemistry, Duke University, 124 Science Drive, Durham, NC 27708-0346, USA
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, 213 Research Drive, Durham, NC 27710, USA
| |
Collapse
|
37
|
Rogers MS, Lipscomb JD. Salicylate 5-Hydroxylase: Intermediates in Aromatic Hydroxylation by a Rieske Monooxygenase. Biochemistry 2019; 58:5305-5319. [PMID: 31066545 PMCID: PMC6856394 DOI: 10.1021/acs.biochem.9b00292] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Rieske oxygenases (ROs) catalyze a large range of oxidative chemistry. We have shown that cis-dihydrodiol-forming Rieske dioxygenases first react with their aromatic substrates via an active site nonheme Fe(III)-superoxide; electron transfer from the Rieske cluster then completes the product-forming reaction. Alternatively, two-electron-reduced Fe(III)-peroxo or hydroxo-Fe(V)-oxo activated oxygen intermediates are possible and may be utilized by other ROs to expand the catalytic range. Here, the reaction of a Rieske monooxygenase, salicylate 5-hydroxylase, that does not form a cis-dihydrodiol is examined. Single-turnover kinetic studies show fast binding of salicylate and O2. Transfer of the Rieske electron required to form the gentisate product occurs through bonds over ∼12 Å and must also be very fast. However, the observed rate constant for this reaction is much slower than expected and sensitive to substrate type. This suggests that initial reaction with salicylate occurs using the same Fe(III)-superoxo-level intermediate as Rieske dioxygenases and that this reaction limits the observed rate of electron transfer. A transient intermediate (λmax = 700 nm) with an electron paramagnetic resonance (EPR) at g = 4.3 is observed after the product is formed in the active site. The use of 17O2 (I = 5/2) results in hyperfine broadening of the g = 4.3 signal, showing that gentisate binds to the mononuclear iron via its C5-OH in the intermediate. The chromophore and EPR signal allow study of product release in the catalytic cycle. Comparison of the kinetics of single- and multiple-turnover reactions shows that re-reduction of the metal centers accelerates product release ∼300-fold, providing insight into the regulatory mechanism of ROs.
Collapse
Affiliation(s)
- Melanie S. Rogers
- Department of Biochemistry, Molecular Biology, and Biophysics and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - John D. Lipscomb
- Department of Biochemistry, Molecular Biology, and Biophysics and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
| |
Collapse
|
38
|
|
39
|
Identification of a Novel Saxitoxin Analogue, 12β-Deoxygonyautoxin 3, in the Cyanobacterium, Anabaena circinalis (TA04). Toxins (Basel) 2019; 11:toxins11090539. [PMID: 31527551 PMCID: PMC6784053 DOI: 10.3390/toxins11090539] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/09/2019] [Accepted: 09/10/2019] [Indexed: 12/11/2022] Open
Abstract
Saxitoxin (STX) and its analogues, the potent voltage-gated sodium channel blockers, are biosynthesized by freshwater cyanobacteria and marine dinoflagellates. We previously identified several biosynthetic intermediates in the extract of the cyanobacterium, Anabaena circinalis (TA04), that are primarily produced during the early and middle stages in the biosynthetic pathway to produce STX. These findings allowed us to propose a putative biosynthetic pathway responsible for STX production based on the structures of these intermediates. In the present study, we identified 12β-deoxygonyautoxin 3 (12β-deoxyGTX3), a novel STX analogue produced by A. circinalis (TA04), by comparing the retention time and MS/MS fragmentation pattern with those of synthetic standards using LC-MS. The presence of this compound in A. circinalis (TA04) is consistent with stereoselective enzymatic oxidations at C11 and C12, and 11-O-sulfation, during the late stage of STX biosynthesis, as proposed in previous studies.
Collapse
|
40
|
Lukowski AL, Denomme N, Hinze ME, Hall S, Isom LL, Narayan ARH. Biocatalytic Detoxification of Paralytic Shellfish Toxins. ACS Chem Biol 2019; 14:941-948. [PMID: 30983320 PMCID: PMC6528162 DOI: 10.1021/acschembio.9b00123] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
![]()
Small molecules that bind to voltage-gated
sodium channels (VGSCs)
are promising leads in the treatment of numerous neurodegenerative
diseases and pain. Nature is a highly skilled medicinal chemist in
this regard, designing potent VGSC ligands capable of binding to and
blocking the channel, thereby offering compounds of potential therapeutic
interest. Paralytic shellfish toxins (PSTs), produced by cyanobacteria
and marine dinoflagellates, are examples of these naturally occurring
small molecule VGSC blockers that can potentially be leveraged to
solve human health concerns. Unfortunately, the remarkable potency
of these natural products results in equally exceptional toxicity,
presenting a significant challenge for the therapeutic application
of these compounds. Identifying less potent analogs and convenient
methods for accessing them therefore provides an attractive approach
to developing molecules with enhanced therapeutic potential. Fortunately,
Nature has evolved tools to modulate the toxicity of PSTs through
selective hydroxylation, sulfation, and desulfation of the core scaffold.
Here, we demonstrate the function of enzymes encoded in cyanobacterial
PST biosynthetic gene clusters that have evolved specifically for
the sulfation of highly functionalized PSTs, the substrate scope of
these enzymes, and elucidate the biosynthetic route from saxitoxin
to monosulfated gonyautoxins and disulfated C-toxins. Finally, the
binding affinities of the nonsulfated, monosulfated, and disulfated
products of these enzymatic reactions have been evaluated for VGSC
binding affinity using mouse whole brain membrane preparations to
provide an assessment of relative toxicity. These data demonstrate
the unique detoxification effect of sulfotransferases in PST biosynthesis,
providing a potential mechanism for the development of more attractive
PST-derived therapeutic analogs.
Collapse
Affiliation(s)
| | | | | | - Sherwood Hall
- United States Food and Drug Administration, College Park, Maryland 20740, United States
| | | | | |
Collapse
|
41
|
Lukowski AL, Narayan ARH. Natural Voltage-Gated Sodium Channel Ligands: Biosynthesis and Biology. Chembiochem 2019; 20:1231-1241. [PMID: 30605564 PMCID: PMC6579537 DOI: 10.1002/cbic.201800754] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Indexed: 12/18/2022]
Abstract
Natural product biosynthetic pathways are composed of enzymes that use powerful chemistry to assemble complex molecules. Small molecule neurotoxins are examples of natural products with intricate scaffolds which often have high affinities for their biological targets. The focus of this Minireview is small molecule neurotoxins targeting voltage-gated sodium channels (VGSCs) and the state of knowledge on their associated biosynthetic pathways. There are three small molecule neurotoxin receptor sites on VGSCs associated with three different classes of molecules: guanidinium toxins, alkaloid toxins, and ladder polyethers. Each of these types of toxins have unique structural features which are assembled by biosynthetic enzymes and the extent of information known about these enzymes varies among each class. The biosynthetic enzymes involved in the formation of these toxins have the potential to become useful tools in the efficient synthesis of VGSC probes.
Collapse
Affiliation(s)
- April L Lukowski
- Program in Chemical Biology, University of Michigan, 210 Washtenaw Ave., Ann Arbor, MI, 48109, USA
| | - Alison R H Narayan
- Life Sciences Institute, University of Michigan, 210 Washtenaw Ave., Ann Arbor, MI, 48109, USA
- Department of Chemistry, University of Michigan, 930 N University Ave., Ann Arbor, MI, 48109, USA
- Program in Chemical Biology, University of Michigan, 210 Washtenaw Ave., Ann Arbor, MI, 48109, USA
| |
Collapse
|
42
|
D'Agostino PM, Boundy MJ, Harwood TD, Carmichael WW, Neilan BA, Wood SA. Re-evaluation of paralytic shellfish toxin profiles in cyanobacteria using hydrophilic interaction liquid chromatography-tandem mass spectrometry. Toxicon 2019; 158:1-7. [DOI: 10.1016/j.toxicon.2018.11.301] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 10/12/2018] [Accepted: 11/18/2018] [Indexed: 10/27/2022]
|
43
|
Cullen A, Pearson LA, Mazmouz R, Liu T, Soeriyadi AH, Ongley SE, Neilan BA. Heterologous expression and biochemical characterisation of cyanotoxin biosynthesis pathways. Nat Prod Rep 2019; 36:1117-1136. [DOI: 10.1039/c8np00063h] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This review discusses cyanotoxin biosynthetic pathways and highlights the heterologous expression and biochemical studies used to characterise them.
Collapse
Affiliation(s)
- Alescia Cullen
- School of Environmental and Life Sciences
- University of Newcastle
- Callaghan 2308
- Australia
| | - Leanne A. Pearson
- School of Environmental and Life Sciences
- University of Newcastle
- Callaghan 2308
- Australia
| | - Rabia Mazmouz
- School of Environmental and Life Sciences
- University of Newcastle
- Callaghan 2308
- Australia
| | - Tianzhe Liu
- School of Biotechnology and Biomolecular Sciences
- The University of New South Wales
- Sydney 2052
- Australia
| | - Angela H. Soeriyadi
- School of Biotechnology and Biomolecular Sciences
- The University of New South Wales
- Sydney 2052
- Australia
| | - Sarah E. Ongley
- School of Environmental and Life Sciences
- University of Newcastle
- Callaghan 2308
- Australia
| | - Brett A. Neilan
- School of Environmental and Life Sciences
- University of Newcastle
- Callaghan 2308
- Australia
| |
Collapse
|
44
|
Abstract
A personal selection of 32 recent papers is presented covering various aspects of current developments in bioorganic chemistry and novel natural products such as kadsuraol A from Kadsura longipedunculata.
Collapse
Affiliation(s)
- Robert A Hill
- School of Chemistry, Glasgow University, Glasgow, G12 8QQ, UK.
| | | |
Collapse
|