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Bashiri G. F 420-dependent transformations in biosynthesis of secondary metabolites. Curr Opin Chem Biol 2024; 80:102468. [PMID: 38776765 DOI: 10.1016/j.cbpa.2024.102468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2024] [Revised: 05/01/2024] [Accepted: 05/01/2024] [Indexed: 05/25/2024]
Abstract
Cofactor F420 has been historically known as the "methanogenic redox cofactor". It is now recognised that F420 has essential roles in the primary and secondary metabolism of archaea and bacteria. Recent discoveries highlight the role of F420 as a redox cofactor in the biosynthesis of various natural products, including ribosomally synthesised and post-translationally modified peptides, and a new class of nicotinamide adenine dinucleotide-based secondary metabolites. With the vast availability of (meta)genomic data, the identification of uncharacterised F420-dependent enzymes offers the potential for discovering novel secondary metabolites, presenting valuable prospects for clinical and biotechnological applications.
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Affiliation(s)
- Ghader Bashiri
- Laboratory of Microbial Biochemistry and Biotechnology, School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand.
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2
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Schluchter WM, Babin CH, Liu X, Bieller A, Shen G, Alvey RM, Bryant DA. Loss of Biliverdin Reductase Increases Oxidative Stress in the Cyanobacterium Synechococcus sp. PCC 7002. Microorganisms 2023; 11:2593. [PMID: 37894251 PMCID: PMC10608806 DOI: 10.3390/microorganisms11102593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 10/13/2023] [Accepted: 10/17/2023] [Indexed: 10/29/2023] Open
Abstract
Oxygenic photosynthesis requires metal-rich cofactors and electron-transfer components that can produce reactive oxygen species (ROS) that are highly toxic to cyanobacterial cells. Biliverdin reductase (BvdR) reduces biliverdin IXα to bilirubin, which is a potent scavenger of radicals and ROS. The enzyme is widespread in mammals but is also found in many cyanobacteria. We show that a previously described bvdR mutant of Synechocystis sp. PCC 6803 contained a secondary deletion mutation in the cpcB gene. The bvdR gene from Synechococcus sp. PCC 7002 was expressed in Escherichia coli, and recombinant BvdR was purified and shown to reduce biliverdin to bilirubin. The bvdR gene was successfully inactivated in Synechococcus sp. PCC 7002, a strain that is naturally much more tolerant of high light and ROS than Synechocystis sp. PCC 6803. The bvdR mutant strain, BR2, had lower total phycobiliprotein and chlorophyll levels than wild-type cells. As determined using whole-cell fluorescence at 77 K, the photosystem I levels were also lower than those in wild-type cells. The BR2 mutant had significantly higher ROS levels compared to wild-type cells after exposure to high light for 30 min. Together, these results suggest that bilirubin plays an important role as a scavenger for ROS in Synechococcus sp. PCC 7002. The oxidation of bilirubin by ROS could convert bilirubin to biliverdin IXα, and thus BvdR might be important for regenerating bilirubin. These results further suggest that BvdR is a key component of a scavenging cycle by which cyanobacteria protect themselves from the toxic ROS byproducts generated during oxygenic photosynthesis.
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Affiliation(s)
- Wendy M. Schluchter
- Department of Biological Sciences, University of New Orleans, New Orleans, LA 70148, USA; (C.H.B.); (X.L.); (A.B.)
| | - Courtney H. Babin
- Department of Biological Sciences, University of New Orleans, New Orleans, LA 70148, USA; (C.H.B.); (X.L.); (A.B.)
| | - Xindi Liu
- Department of Biological Sciences, University of New Orleans, New Orleans, LA 70148, USA; (C.H.B.); (X.L.); (A.B.)
| | - Amori Bieller
- Department of Biological Sciences, University of New Orleans, New Orleans, LA 70148, USA; (C.H.B.); (X.L.); (A.B.)
| | - Gaozhong Shen
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA (R.M.A.); (D.A.B.)
| | - Richard M. Alvey
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA (R.M.A.); (D.A.B.)
- Biology Department, Bloomington, Illinois Wesleyan University, Bloomington, IL 61702, USA
| | - Donald A. Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA (R.M.A.); (D.A.B.)
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3
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Perez-Ortiz G, Sidda JD, Peate J, Ciccarelli D, Ding Y, Barry SM. Production of copropophyrin III, biliverdin and bilirubin by the rufomycin producer, Streptomyces atratus. Front Microbiol 2023; 14:1092166. [PMID: 37007481 PMCID: PMC10060970 DOI: 10.3389/fmicb.2023.1092166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 01/31/2023] [Indexed: 03/18/2023] Open
Abstract
Heme is best known for its role as a versatile prosthetic group in prokaryotic and eukaryotic proteins with diverse biological functions including gas and electron transport, as well as a wide array of redox chemistry. However, free heme and related tetrapyrroles also have important roles in the cell. In several bacterial strains, heme biosynthetic precursors and degradation products have been proposed to function as signaling molecules, ion chelators, antioxidants and photoprotectants. While the uptake and degradation of heme by bacterial pathogens is well studied, less is understood about the physiological role of these processes and their products in non-pathogenic bacteria. Streptomyces are slow growing soil bacteria known for their extraordinary capacity to produce complex secondary metabolites, particularly many clinically used antibiotics. Here we report the unambiguous identification of three tetrapyrrole metabolites from heme metabolism, coproporphyrin III, biliverdin and bilirubin, in culture extracts of the rufomycin antibiotic producing Streptomyces atratus DSM41673. We propose that biliverdin and bilirubin may combat oxidative stress induced by nitric oxide production during rufomycin biosynthesis, and indicate the genes involved in their production. This is, to our knowledge, the first report of the production of all three of these tetrapyrroles by a Streptomycete.
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Affiliation(s)
| | | | | | | | | | - Sarah M. Barry
- Department of Chemistry, Faculty of Natural & Mathematical Sciences, King’s College London, London, United Kingdom
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4
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Kang SW, Antoney J, Frkic RL, Lupton DW, Speight R, Scott C, Jackson CJ. Asymmetric Ene-Reduction of α,β-Unsaturated Compounds by F 420-Dependent Oxidoreductases A Enzymes from Mycobacterium smegmatis. Biochemistry 2023; 62:873-891. [PMID: 36637210 DOI: 10.1021/acs.biochem.2c00557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
The stereoselective reduction of alkenes conjugated to electron-withdrawing groups by ene-reductases has been extensively applied to the commercial preparation of fine chemicals. Although several different enzyme families are known to possess ene-reductase activity, the old yellow enzyme (OYE) family has been the most thoroughly investigated. Recently, it was shown that a subset of ene-reductases belonging to the flavin/deazaflavin oxidoreductase (FDOR) superfamily exhibit enantioselectivity that is generally complementary to that seen in the OYE family. These enzymes belong to one of several FDOR subgroups that use the unusual deazaflavin cofactor F420. Here, we explore several enzymes of the FDOR-A subgroup, characterizing their substrate range and enantioselectivity with 20 different compounds, identifying enzymes (MSMEG_2027 and MSMEG_2850) that could reduce a wide range of compounds stereoselectively. For example, MSMEG_2027 catalyzed the complete conversion of both isomers of citral to (R)-citronellal with 99% ee, while MSMEG_2850 catalyzed complete conversion of ketoisophorone to (S)-levodione with 99% ee. Protein crystallography combined with computational docking has allowed the observed stereoselectivity to be mechanistically rationalized for two enzymes. These findings add further support for the FDOR and OYE families of ene-reductases displaying general stereocomplementarity to each other and highlight their potential value in asymmetric ene-reduction.
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Affiliation(s)
- Suk Woo Kang
- Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory2601, Australia.,Natural Products Research Center, Korea Institute of Science and Technology (KIST), Gangneung25451, Republic of Korea
| | - James Antoney
- Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory2601, Australia.,School of Biology and Environmental Sciences, Queensland University of Technology, Brisbane, Queensland4000, Australia.,ARC Centre of Excellence in Synthetic Biology, Queensland University of Technology, Brisbane, Queensland4000, Australia
| | - Rebecca L Frkic
- Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory2601, Australia.,ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory2601, Australia
| | - David W Lupton
- School of Chemistry, Monash University, Melbourne, Victoria3800, Australia
| | - Robert Speight
- School of Biology and Environmental Sciences, Queensland University of Technology, Brisbane, Queensland4000, Australia.,ARC Centre of Excellence in Synthetic Biology, Queensland University of Technology, Brisbane, Queensland4000, Australia
| | - Colin Scott
- Land and Water, Commonwealth Scientific and Industrial Research Organisation, Clayton, Victoria3168, Australia.,CSIRO Synthetic Biology Future Science Platform, GPO Box 1700, Canberra, Australian Capital Territory2601, Australia
| | - Colin J Jackson
- Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory2601, Australia.,ARC Centre of Excellence in Synthetic Biology, Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory2601, Australia.,ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory2601, Australia
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5
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Kang SW, Antoney J, Lupton DW, Speight R, Scott C, Jackson CJ. Asymmetric Ene-Reduction by F 420 -Dependent Oxidoreductases B (FDOR-B) from Mycobacterium smegmatis. Chembiochem 2023; 24:e202200797. [PMID: 36716144 DOI: 10.1002/cbic.202200797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/29/2023] [Accepted: 01/30/2023] [Indexed: 01/31/2023]
Abstract
Asymmetric reduction by ene-reductases has received considerable attention in recent decades. While several enzyme families possess ene-reductase activity, the Old Yellow Enzyme (OYE) family has received the most scientific and industrial attention. However, there is a limited substrate range and few stereocomplementary pairs of current ene-reductases, necessitating the development of a complementary class. Flavin/deazaflavin oxidoreductases (FDORs) that use the uncommon cofactor F420 have recently gained attention as ene-reductases for use in biocatalysis due to their stereocomplementarity with OYEs. Although the enzymes of the FDOR-As sub-group have been characterized in this context and reported to catalyse ene-reductions enantioselectively, enzymes from the similarly large, but more diverse, FDOR-B sub-group have not been investigated in this context. In this study, we investigated the activity of eight FDOR-B enzymes distributed across this sub-group, evaluating their specific activity, kinetic properties, and stereoselectivity against α,β-unsaturated compounds. The stereochemical outcomes of the FDOR-Bs are compared with enzymes of the FDOR-A sub-group and OYE family. Computational modelling and induced-fit docking are used to rationalize the observed catalytic behaviour and proposed a catalytic mechanism.
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Affiliation(s)
- Suk Woo Kang
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia.,Natural Products Research Center, Korea Institute of Science and Technology (KIST), Gangneung, 25451 (Republic of, Korea
| | - James Antoney
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia.,School of Biology and Environmental Sciences, Queensland University of Technology, Brisbane, QLD 4000, Australia.,ARC Centre of Excellence in Synthetic Biology, Queensland University of Technology, Brisbane, Queensland, 4000, Australia
| | - David W Lupton
- School of Chemistry, Monash University, Melbourne, Victoria, 3800, Australia
| | - Robert Speight
- School of Biology and Environmental Sciences, Queensland University of Technology, Brisbane, QLD 4000, Australia.,ARC Centre of Excellence in Synthetic Biology, Queensland University of Technology, Brisbane, Queensland, 4000, Australia
| | - Colin Scott
- Environment, Commonwealth Scientific and Industrial Research Organization, GPO Box 1700, Canberra, ACT 2601, Australia
| | - Colin J Jackson
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia.,ARC Centre of Excellence in Synthetic Biology, Australian National University, Canberra, ACT 2601, Australia.,ARC Centre of Excellence for Innovations in Peptide and Protein Science, Australian National University, Canberra, ACT 2601, Australia
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6
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Petushkov VN, Vavilov MV, Ivanov IA, Ziganshin RH, Rodionova NS, Yampolsky IV, Tsarkova AS, Dubinnyi MA. Deazaflavin cofactor boosts earthworms Henlea bioluminescence. Org Biomol Chem 2023; 21:415-427. [PMID: 36530053 DOI: 10.1039/d2ob01946a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The bioluminescence of Siberian earthworms Henlea sp. was found to be enhanced by two low molecular weight activators, termed ActH and ActS, found in the hot extracts. The fluorescence emission maximum of the activators matches the bioluminescence spectrum that peaks at 464 nm. We purified 4.3 and 8.8 micrograms of ActH and ActS from 200 worms and explored them using orbitrap HRMS with deep fragmentation and 1D/2D NMR equipped with cryoprobes. Their chemical structures were ascertained using chemical shift prediction services, structure elucidation software and database searches. ActH was identified as the riboflavin analoge archaeal cofactor F0, namely 7,8-didemethyl-8-hydroxy-5-deazariboflavin. ActS is a novel compound, namely ActH sulfated at the 3' ribityl hydroxyl. We designed and implemented a new four step synthesis strategy forActH that outperformed previous synthetic approaches. The synthetic ActH was identical to the natural one and activated Henlea sp. bioluminescence. The bioluminescence enhancement factor X was measured at different ActH concentrations and the Michaelis constant Km = 0.22 ± 0.01 μM was obtained by nonlinear regression. At an excess of synthetic ActH, the factor X was saturated at Xmax = 33.3 ± 0.5, thus opening an avenue to further characterisation of the Henlea sp. bioluminescence system. ActH did not produce bioluminescence without the luciferin with an as yet unknown chemical structure. We propose that ActH and the novel sulfated deazariboflavin ActS either emit the light of the Henlea sp. bioluminescence and/or accept hydride(s) donor upon luciferin oxidation.
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Affiliation(s)
- Valentin N Petushkov
- Institute of Biophysics, Krasnoyarsk Research Center, Siberian Branch, Russian Academy of Sciences, Akademgorodok, 660036, Krasnoyarsk, Russia
| | - Matvey V Vavilov
- Shemyakin-Ovchinnikov Institute of bioorganic chemistry, Russian academy of Sciences GSP-7, Miklukho-Maklaya str., 16/10, 117997, Moscow, Russia.
| | - Igor A Ivanov
- Shemyakin-Ovchinnikov Institute of bioorganic chemistry, Russian academy of Sciences GSP-7, Miklukho-Maklaya str., 16/10, 117997, Moscow, Russia.
| | - Rustam H Ziganshin
- Shemyakin-Ovchinnikov Institute of bioorganic chemistry, Russian academy of Sciences GSP-7, Miklukho-Maklaya str., 16/10, 117997, Moscow, Russia.
| | - Natalia S Rodionova
- Institute of Biophysics, Krasnoyarsk Research Center, Siberian Branch, Russian Academy of Sciences, Akademgorodok, 660036, Krasnoyarsk, Russia
| | - Ilia V Yampolsky
- Shemyakin-Ovchinnikov Institute of bioorganic chemistry, Russian academy of Sciences GSP-7, Miklukho-Maklaya str., 16/10, 117997, Moscow, Russia.
| | - Aleksandra S Tsarkova
- Shemyakin-Ovchinnikov Institute of bioorganic chemistry, Russian academy of Sciences GSP-7, Miklukho-Maklaya str., 16/10, 117997, Moscow, Russia. .,Pirogov Russian National Research Medical University, 117997 Moscow, Russia
| | - Maxim A Dubinnyi
- Shemyakin-Ovchinnikov Institute of bioorganic chemistry, Russian academy of Sciences GSP-7, Miklukho-Maklaya str., 16/10, 117997, Moscow, Russia. .,Moscow Institute of Physics and Technology (State University), 9 Institutskiy per., Dolgoprudny, Moscow Region 141700, Russia
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7
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Grinter R, Greening C. Cofactor F420: an expanded view of its distribution, biosynthesis and roles in bacteria and archaea. FEMS Microbiol Rev 2021; 45:fuab021. [PMID: 33851978 PMCID: PMC8498797 DOI: 10.1093/femsre/fuab021] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 04/11/2021] [Indexed: 12/11/2022] Open
Abstract
Many bacteria and archaea produce the redox cofactor F420. F420 is structurally similar to the cofactors FAD and FMN but is catalytically more similar to NAD and NADP. These properties allow F420 to catalyze challenging redox reactions, including key steps in methanogenesis, antibiotic biosynthesis and xenobiotic biodegradation. In the last 5 years, there has been much progress in understanding its distribution, biosynthesis, role and applications. Whereas F420 was previously thought to be confined to Actinobacteria and Euryarchaeota, new evidence indicates it is synthesized across the bacterial and archaeal domains, as a result of extensive horizontal and vertical biosynthetic gene transfer. F420 was thought to be synthesized through one biosynthetic pathway; however, recent advances have revealed variants of this pathway and have resolved their key biosynthetic steps. In parallel, new F420-dependent biosynthetic and metabolic processes have been discovered. These advances have enabled the heterologous production of F420 and identified enantioselective F420H2-dependent reductases for biocatalysis. New research has also helped resolve how microorganisms use F420 to influence human and environmental health, providing opportunities for tuberculosis treatment and methane mitigation. A total of 50 years since its discovery, multiple paradigms associated with F420 have shifted, and new F420-dependent organisms and processes continue to be discovered.
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Affiliation(s)
- Rhys Grinter
- Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - Chris Greening
- Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
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9
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Wang J, Guo Q, Li X, Wang X, Liu L. The Arabidopsis locus AT3G03890 encodes a dimeric β-barrel protein implicated in heme degradation. Biochem J 2020; 477:BCJ20200712. [PMID: 33284325 DOI: 10.1042/bcj20200712] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 12/03/2020] [Accepted: 12/04/2020] [Indexed: 02/24/2024]
Abstract
Plant tetrapyrroles, including heme and bilins, are synthesized in plastids. Heme oxygenase (HO) catalyzes the oxidative cleavage of heme to the linear tetrapyrrole biliverdin as the initial step in bilin biosynthesis. Besides the canonical α-helical HO that is conserved from prokaryotes to human, a subfamily of non-canonical dimeric β-barrel HO has been found in bacteria. In this work, we discovered that the Arabidopsis locus AT3G03890 encodes a dimeric β-barrel protein that is structurally related to the putative non-canonical HO and is located in chloroplasts. The recombinant protein was able to bind and degrade heme in a manner different from known HO proteins. Crystal structure of the heme-protein complex reveals that the heme-binding site is in the interdimer interface and the heme iron is coordinated by a fixed water molecule. Our results identify a new protein that may function additionally in the tetrapyrrole biosynthetic pathway.
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Affiliation(s)
| | - Qi Guo
- Institute of Botany, Chinease Academy of Sciences, Beijing, China
| | - Xiaoyi Li
- Institute of Botany, Chinease Academy of Sciences, Beijing, China
| | | | - Lin Liu
- Anhui University, Hefei, China
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10
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Sugishima M, Wada K, Fukuyama K. Recent Advances in the Understanding of the Reaction Chemistries of the Heme Catabolizing Enzymes HO and BVR Based on High Resolution Protein Structures. Curr Med Chem 2020; 27:3499-3518. [PMID: 30556496 PMCID: PMC7509768 DOI: 10.2174/0929867326666181217142715] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 11/21/2018] [Accepted: 12/11/2018] [Indexed: 01/15/2023]
Abstract
In mammals, catabolism of the heme group is indispensable for life. Heme is first cleaved by the enzyme Heme Oxygenase (HO) to the linear tetrapyrrole Biliverdin IXα (BV), and BV is then converted into bilirubin by Biliverdin Reductase (BVR). HO utilizes three Oxygen molecules (O2) and seven electrons supplied by NADPH-cytochrome P450 oxidoreductase (CPR) to open the heme ring and BVR reduces BV through the use of NAD(P)H. Structural studies of HOs, including substrate-bound, reaction intermediate-bound, and several specific inhibitor-bound forms, reveal details explaining substrate binding to HO and mechanisms underlying-specific HO reaction progression. Cryo-trapped structures and a time-resolved spectroscopic study examining photolysis of the bond between the distal ligand and heme iron demonstrate how CO, produced during the HO reaction, dissociates from the reaction site with a corresponding conformational change in HO. The complex structure containing HO and CPR provides details of how electrons are transferred to the heme-HO complex. Although the tertiary structure of BVR and its complex with NAD+ was determined more than 10 years ago, the catalytic residues and the reaction mechanism of BVR remain unknown. A recent crystallographic study examining cyanobacterial BVR in complex with NADP+ and substrate BV provided some clarification regarding these issues. Two BV molecules are bound to BVR in a stacked manner, and one BV may assist in the reductive catalysis of the other BV. In this review, recent advances illustrated by biochemical, spectroscopic, and crystallographic studies detailing the chemistry underlying the molecular mechanism of HO and BVR reactions are presented.
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Affiliation(s)
- Masakazu Sugishima
- Department of Medical Biochemistry, Kurume University School of Medicine, Kurume, Japan
| | - Kei Wada
- Department of Medical Sciences, University of Miyazaki, Miyazaki, Japan
| | - Keiichi Fukuyama
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Japan.,Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Japan
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11
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Chao A, Burley KH, Sieminski PJ, de Miranda R, Chen X, Mobley DL, Goulding CW. Structure of a Mycobacterium tuberculosis Heme-Degrading Protein, MhuD, Variant in Complex with Its Product. Biochemistry 2019; 58:4610-4620. [PMID: 31638374 DOI: 10.1021/acs.biochem.9b00726] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis, requires iron for survival. In Mtb, MhuD is the cytosolic protein that degrades imported heme. MhuD is distinct, in both sequence and structure, from canonical heme oxygenases (HOs) but homologous with IsdG-type proteins. Canonical HO is found mainly in eukaryotes, while IsdG-type proteins are predominantly found in prokaryotes, including pathogens. While there are several published structures of MhuD and other IsdG-type proteins in complex with the heme substrate, no structures of IsdG-type proteins in complex with a product have been reported, unlike the case for HOs. We recently showed that the Mtb variant MhuD-R26S produces biliverdin IXα (αBV) rather than the wild-type mycobilin isomers. Given that mycobilin and other IsdG-type protein products like staphylobilin are difficult to isolate in quantities sufficient for structure determination, here we use the MhuD-R26S variant and its product αBV as a proxy to study the IsdG-type protein-product complex. First, we show that αBV has a nanomolar affinity for MhuD and the R26S variant. Second, we determined the MhuD-R26S-αBV complex structure to 2.5 Å, which reveals two notable features: (1) two αBV molecules bound per active site and (2) a novel α-helix (α3) that was not observed in previous MhuD-heme structures. Finally, through molecular dynamics simulations, we show that α3 is stable with the proximal αBV alone. MhuD's high affinity for the product and the observed structural and electrostatic changes that accompany substrate turnover suggest that there may be an unidentified class of proteins that are responsible for the extraction of products from MhuD and other IsdG-type proteins.
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12
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Cofactor F420-Dependent Enzymes: An Under-Explored Resource for Asymmetric Redox Biocatalysis. Catalysts 2019. [DOI: 10.3390/catal9100868] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The asymmetric reduction of enoates, imines and ketones are among the most important reactions in biocatalysis. These reactions are routinely conducted using enzymes that use nicotinamide cofactors as reductants. The deazaflavin cofactor F420 also has electrochemical properties that make it suitable as an alternative to nicotinamide cofactors for use in asymmetric reduction reactions. However, cofactor F420-dependent enzymes remain under-explored as a resource for biocatalysis. This review considers the cofactor F420-dependent enzyme families with the greatest potential for the discovery of new biocatalysts: the flavin/deazaflavin-dependent oxidoreductases (FDORs) and the luciferase-like hydride transferases (LLHTs). The characterized F420-dependent reductions that have the potential for adaptation for biocatalysis are discussed, and the enzymes best suited for use in the reduction of oxidized cofactor F420 to allow cofactor recycling in situ are considered. Further discussed are the recent advances in the production of cofactor F420 and its functional analog FO-5′-phosphate, which remains an impediment to the adoption of this family of enzymes for industrial biocatalytic processes. Finally, the prospects for the use of this cofactor and dependent enzymes as a resource for industrial biocatalysis are discussed.
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13
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Yi WJ, Han YS, Wei LL, Shi LY, Huang H, Jiang TT, Li ZB, Chen J, Hu YT, Tu HH, Li JC. l-Histidine, arachidonic acid, biliverdin, and l-cysteine-glutathione disulfide as potential biomarkers for cured pulmonary tuberculosis. Biomed Pharmacother 2019; 116:108980. [PMID: 31125821 DOI: 10.1016/j.biopha.2019.108980] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 04/15/2019] [Accepted: 05/08/2019] [Indexed: 11/25/2022] Open
Abstract
Lack of laboratory standards for cured tuberculosis (TB) can lead to early discharge of untreated TB patients from the hospital, resulting in increased risk of TB spread and of developing drug resistant Mycobacterium tuberculosis (Mtb). We used ultra-high performance liquid chromatography coupled with mass spectrometry (LC-MS) to detect heparin anticoagulant in plasma of untreated TB patients, two-month treated TB patients, cured TB subjects, and healthy controls. Screening of differentially expressed metabolites resulted in identification of four differentially expressed metabolites such as, l-Histidine, Arachidonic acid (AA), Biliverdin, and l-Cysteine-glutathione disulfide after 6 months of TB treatment. Among them, l-Cysteine-glutathione disulfide and AA could be identified after 2 months of TB treatment. We established a cured TB model with an area under the curve (AUC) of 0.909 (95% CI, 0.802-0.970), 86.2% sensitivity, and 85.2% specificity. The diagnostic model fitted from the four differential metabolites in combination (l-Histidine, AA, Biliverdin, and l-Cysteine-glutathione disulfide) can be used as potential biomarkers for cured TB. Our study provided laboratory standards for hospital discharge of TB patients, as well as experimental basis for evaluating the efficacy of anti-TB drugs.
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Affiliation(s)
- Wen-Jing Yi
- Institute of Cell Biology, Zhejiang University School of Medicine, Hangzhou, 310058, China.
| | - Yu-Shuai Han
- Institute of Cell Biology, Zhejiang University School of Medicine, Hangzhou, 310058, China.
| | - Li-Liang Wei
- Department of Pneumology, Shaoxing Municipal Hospital, Shaoxing, 312000, China.
| | - Li-Ying Shi
- Department of Clinical Laboratory, Zhejiang Hospital, Hangzhou, 310058, China.
| | - Huai Huang
- School of Medicine, South China University of Technology, Guangzhou, 510000, China.
| | - Ting-Ting Jiang
- School of Medicine, South China University of Technology, Guangzhou, 510000, China.
| | - Zhi-Bin Li
- Institute of Cell Biology, Zhejiang University School of Medicine, Hangzhou, 310058, China.
| | - Jing Chen
- Institute of Cell Biology, Zhejiang University School of Medicine, Hangzhou, 310058, China.
| | - Yu-Ting Hu
- School of Medicine, South China University of Technology, Guangzhou, 510000, China.
| | - Hui-Hui Tu
- Institute of Cell Biology, Zhejiang University School of Medicine, Hangzhou, 310058, China.
| | - Ji-Cheng Li
- Institute of Cell Biology, Zhejiang University School of Medicine, Hangzhou, 310058, China.
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14
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Benini S, Haouz A, Proux F, Alzari P, Wilson K. The crystal structure of Rv2991 from Mycobacterium tuberculosis: An F 420 binding protein with unknown function. J Struct Biol 2019; 206:216-224. [PMID: 30890426 DOI: 10.1016/j.jsb.2019.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 03/13/2019] [Accepted: 03/14/2019] [Indexed: 11/25/2022]
Abstract
The crystal structure of the conserved hypothetical protein Rv2991 from Mycobacterium tuberculosis has been solved by SAD using seleno-methionine substituted protein. The dimeric biological assembly and the sequence and fold conservation are typical of F420 cofactor binding enzymes. Despite Rv2991 still being of unknown function, sequence and structural comparison with similar proteins enable a role to be proposed for its C-terminal stretch of residues in recognizing and orienting the substrate. In addition, the C-terminus is involved in both protein folding and determining the size of the active site cavity.
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Affiliation(s)
- Stefano Benini
- Bioorganic Chemistry and Bio-Crystallography Laboratory (B(2)Cl), Faculty of Science and Technology, Free University of Bolzano, Piazza Università 5, Bolzano 39100, Italy.
| | - Ahmed Haouz
- C2RT-Plateforme de cristallographie, Institut Pasteur, CNRS UMR 3528, 75724 Paris Cedex 15, France
| | - Florence Proux
- C2RT-Plateforme de cristallographie, Institut Pasteur, CNRS UMR 3528, 75724 Paris Cedex 15, France
| | - Pedro Alzari
- Unité de Microbiologie Structurale, Institut Pasteur, CNRS UMR 3528, Université Paris Diderot, Sorbonne Paris Cité, 75724 Paris Cedex 15, France
| | - Keith Wilson
- York Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5DD, UK
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15
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Richard KL, Kelley BR, Johnson JG. Heme Uptake and Utilization by Gram-Negative Bacterial Pathogens. Front Cell Infect Microbiol 2019; 9:81. [PMID: 30984629 PMCID: PMC6449446 DOI: 10.3389/fcimb.2019.00081] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 03/08/2019] [Indexed: 02/06/2023] Open
Abstract
Iron is a transition metal utilized by nearly all forms of life for essential cellular processes, such as DNA synthesis and cellular respiration. During infection by bacterial pathogens, the host utilizes various strategies to sequester iron in a process termed, nutritional immunity. To circumvent these defenses, Gram-negative pathogens have evolved numerous mechanisms to obtain iron from heme. In this review we outline the systems that exist in several Gram-negative pathogens that are associated with heme transport and utilization, beginning with hemolysis and concluding with heme degradation. In addition, Gram-negative pathogens must also closely regulate the intracellular concentrations of iron and heme, since high levels of iron can lead to the generation of toxic reactive oxygen species. As such, we also provide several examples of regulatory pathways that control heme utilization, showing that co-regulation with other cellular processes is complex and often not completely understood.
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Affiliation(s)
- Kaylie L Richard
- Department of Microbiology, University of Tennessee, Knoxville, TN, United States
| | - Brittni R Kelley
- Department of Microbiology, University of Tennessee, Knoxville, TN, United States
| | - Jeremiah G Johnson
- Department of Microbiology, University of Tennessee, Knoxville, TN, United States
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16
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Harold LK, Antoney J, Ahmed FH, Hards K, Carr PD, Rapson T, Greening C, Jackson CJ, Cook GM. FAD-sequestering proteins protect mycobacteria against hypoxic and oxidative stress. J Biol Chem 2018; 294:2903-2912. [PMID: 30567740 DOI: 10.1074/jbc.ra118.006237] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 12/14/2018] [Indexed: 12/13/2022] Open
Abstract
The ability to persist in the absence of growth triggered by low oxygen levels is a critical process for the survival of mycobacterial species in many environmental niches. MSMEG_5243 (fsq), a gene of unknown function in Mycobacterium smegmatis, is up-regulated in response to hypoxia and regulated by DosRDosS/DosT, an oxygen- and redox-sensing two-component system that is highly conserved in mycobacteria. In this communication, we demonstrate that MSMEG_5243 is a flavin-sequestering protein and henceforth refer to it as Fsq. Using an array of biochemical and structural analyses, we show that Fsq is a member of the diverse superfamily of flavin- and deazaflavin-dependent oxidoreductases (FDORs) and is widely distributed in mycobacterial species. We created a markerless deletion mutant of fsq and demonstrate that fsq is required for cell survival during hypoxia. Using fsq deletion and overexpression, we found that fsq enhances cellular resistance to hydrogen peroxide treatment. The X-ray crystal structure of Fsq, solved to 2.7 Å, revealed a homodimeric organization with FAD bound noncovalently. The Fsq structure also uncovered no potential substrate-binding cavities, as the FAD is fully enclosed, and electrochemical studies indicated that the Fsq:FAD complex is relatively inert and does not share common properties with electron-transfer proteins. Taken together, our results suggest that Fsq reduces the formation of reactive oxygen species (ROS) by sequestering free FAD during recovery from hypoxia, thereby protecting the cofactor from undergoing autoxidation to produce ROS. This finding represents a new paradigm in mycobacterial adaptation to hypoxia.
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Affiliation(s)
- Liam K Harold
- From the Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Private Bag 92019, Auckland 1042, New Zealand
| | - James Antoney
- Research School of Chemistry, The Australian National University, Canberra, Australia.,The Commonwealth Scientific and Industrial Research Organisation, Land and Water Flagship, Canberra, Australian Capital Territory, Australia, and
| | - F Hafna Ahmed
- Research School of Chemistry, The Australian National University, Canberra, Australia.,The Commonwealth Scientific and Industrial Research Organisation, Land and Water Flagship, Canberra, Australian Capital Territory, Australia, and
| | - Kiel Hards
- From the Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Paul D Carr
- Research School of Chemistry, The Australian National University, Canberra, Australia
| | - Trevor Rapson
- The Commonwealth Scientific and Industrial Research Organisation, Land and Water Flagship, Canberra, Australian Capital Territory, Australia, and
| | - Chris Greening
- The Commonwealth Scientific and Industrial Research Organisation, Land and Water Flagship, Canberra, Australian Capital Territory, Australia, and .,School of Biological Sciences, Monash University, Melbourne, Australia
| | - Colin J Jackson
- Research School of Chemistry, The Australian National University, Canberra, Australia,
| | - Gregory M Cook
- From the Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand, .,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Private Bag 92019, Auckland 1042, New Zealand
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17
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Ichikawa H, Bashiri G, Kelly WL. Biosynthesis of the Thiopeptins and Identification of an F 420H 2-Dependent Dehydropiperidine Reductase. J Am Chem Soc 2018; 140:10749-10756. [PMID: 30118217 PMCID: PMC6193465 DOI: 10.1021/jacs.8b04238] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Thiopeptins are highly decorated thiopeptide antibiotics similar in structure to thiostrepton A and harbor two unusual features. All thiopeptins contain a thioamide, a rare moiety among natural products, and a subset of thiopeptins present with a piperidine in the core macrocycle rather than the more oxidated dehydropiperidine or pyridine rings typically observed in the thiopeptides. Here, we report the identification of the thiopeptin biosynthetic gene ( tpn) cluster in Streptomyces tateyamensis and the gene product, TpnL, which shows sequence similarity to (deaza)flavin-dependent oxidoreductases. Heterologous expression of TpnL in the thiostrepton A producer Streptomyces laurentii led to the production of a piperidine-containing analogue. Binding studies revealed that TpnL preferentially binds the deazaflavin cofactor coenzyme F420, and in vitro reconstitution of TpnL activity confirmed that this enzyme is an F420H2-dependent dehydropiperidine reductase. The identification of TpnL and its activity establishes the basis for the piperidine-containing series a thiopeptides, one of the five main structural groups of this diverse family of antibiotics.
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Affiliation(s)
- Hiro Ichikawa
- School of Chemistry and Biochemistry and the Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Ghader Bashiri
- Laboratory of Structural Biology and Maurice Wilkins Center for Molecular Biodiscovery, School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand
| | - Wendy L. Kelly
- School of Chemistry and Biochemistry and the Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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18
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Ney B, Carere CR, Sparling R, Jirapanjawat T, Stott MB, Jackson CJ, Oakeshott JG, Warden AC, Greening C. Cofactor Tail Length Modulates Catalysis of Bacterial F 420-Dependent Oxidoreductases. Front Microbiol 2017; 8:1902. [PMID: 29021791 PMCID: PMC5623714 DOI: 10.3389/fmicb.2017.01902] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 09/15/2017] [Indexed: 11/13/2022] Open
Abstract
F420 is a microbial cofactor that mediates a wide range of physiologically important and industrially relevant redox reactions, including in methanogenesis and tetracycline biosynthesis. This deazaflavin comprises a redox-active isoalloxazine headgroup conjugated to a lactyloligoglutamyl tail. Here we studied the catalytic significance of the oligoglutamate chain, which differs in length between bacteria and archaea. We purified short-chain F420 (two glutamates) from a methanogen isolate and long-chain F420 (five to eight glutamates) from a recombinant mycobacterium, confirming their different chain lengths by HPLC and LC/MS analysis. F420 purified from both sources was catalytically compatible with purified enzymes from the three major bacterial families of F420-dependent oxidoreductases. However, long-chain F420 bound to these enzymes with a six- to ten-fold higher affinity than short-chain F420. The cofactor side chain also significantly modulated the kinetics of the enzymes, with long-chain F420 increasing the substrate affinity (lower Km) but reducing the turnover rate (lower kcat) of the enzymes. Molecular dynamics simulations and comparative structural analysis suggest that the oligoglutamate chain of F420 makes dynamic electrostatic interactions with conserved surface residues of the oxidoreductases while the headgroup binds the catalytic site. In conjunction with the kinetic data, this suggests that electrostatic interactions made by the oligoglutamate tail result in higher-affinity, lower-turnover catalysis. Physiologically, we propose that bacteria have selected for long-chain F420 to better control cellular redox reactions despite tradeoffs in catalytic rate. Conversely, this suggests that industrial use of shorter-length F420 will greatly increase the rates of bioremediation and biocatalysis processes relying on purified F420-dependent oxidoreductases.
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Affiliation(s)
- Blair Ney
- School of Biological Sciences, Monash University, Clayton, VIC, Australia.,Land and Water Flagship, The Commonwealth Scientific and Industrial Research Organisation, Acton, ACT, Australia
| | - Carlo R Carere
- GNS Science, Wairakei Research Centre, Lower Hutt, New Zealand
| | - Richard Sparling
- GNS Science, Wairakei Research Centre, Lower Hutt, New Zealand.,Department of Microbiology, University of Manitoba, Winnipeg, MB, Canada
| | | | - Matthew B Stott
- GNS Science, Wairakei Research Centre, Lower Hutt, New Zealand
| | - Colin J Jackson
- Research School of Chemistry, Australian National University, Acton, ACT, Australia
| | - John G Oakeshott
- Land and Water Flagship, The Commonwealth Scientific and Industrial Research Organisation, Acton, ACT, Australia
| | - Andrew C Warden
- Land and Water Flagship, The Commonwealth Scientific and Industrial Research Organisation, Acton, ACT, Australia
| | - Chris Greening
- School of Biological Sciences, Monash University, Clayton, VIC, Australia.,Land and Water Flagship, The Commonwealth Scientific and Industrial Research Organisation, Acton, ACT, Australia
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19
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Gerlt JA. Genomic Enzymology: Web Tools for Leveraging Protein Family Sequence-Function Space and Genome Context to Discover Novel Functions. Biochemistry 2017; 56:4293-4308. [PMID: 28826221 PMCID: PMC5569362 DOI: 10.1021/acs.biochem.7b00614] [Citation(s) in RCA: 136] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
![]()
The exponentially increasing number
of protein and nucleic acid
sequences provides opportunities to discover novel enzymes, metabolic
pathways, and metabolites/natural products, thereby adding to our
knowledge of biochemistry and biology. The challenge has evolved from
generating sequence information to mining the databases to integrating
and leveraging the available information, i.e., the availability of
“genomic enzymology” web tools. Web tools that allow
identification of biosynthetic gene clusters are widely used by the
natural products/synthetic biology community, thereby facilitating
the discovery of novel natural products and the enzymes responsible
for their biosynthesis. However, many novel enzymes with interesting
mechanisms participate in uncharacterized small-molecule metabolic
pathways; their discovery and functional characterization also can
be accomplished by leveraging information in protein and nucleic acid
databases. This Perspective focuses on two genomic enzymology web
tools that assist the discovery novel metabolic pathways: (1) Enzyme
Function Initiative-Enzyme Similarity Tool (EFI-EST) for generating
sequence similarity networks to visualize and analyze sequence–function
space in protein families and (2) Enzyme Function Initiative-Genome
Neighborhood Tool (EFI-GNT) for generating genome neighborhood networks
to visualize and analyze the genome context in microbial and fungal
genomes. Both tools have been adapted to other applications to facilitate
target selection for enzyme discovery and functional characterization.
As the natural products community has demonstrated, the enzymology
community needs to embrace the essential role of web tools that allow
the protein and genome sequence databases to be leveraged for novel
insights into enzymological problems.
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Affiliation(s)
- John A Gerlt
- Departments of Biochemistry and Chemistry, Institute for Genomic Biology, University of Illinois , Urbana-Champaign Urbana, Illinois 61801, United States
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20
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Greening C, Jirapanjawat T, Afroze S, Ney B, Scott C, Pandey G, Lee BM, Russell RJ, Jackson CJ, Oakeshott JG, Taylor MC, Warden AC. Mycobacterial F 420H 2-Dependent Reductases Promiscuously Reduce Diverse Compounds through a Common Mechanism. Front Microbiol 2017; 8:1000. [PMID: 28620367 PMCID: PMC5449967 DOI: 10.3389/fmicb.2017.01000] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 05/18/2017] [Indexed: 01/24/2023] Open
Abstract
An unusual aspect of actinobacterial metabolism is the use of the redox cofactor F420. Studies have shown that actinobacterial F420H2-dependent reductases promiscuously hydrogenate diverse organic compounds in biodegradative and biosynthetic processes. These enzymes therefore represent promising candidates for next-generation industrial biocatalysts. In this work, we undertook the first broad survey of these enzymes as potential industrial biocatalysts by exploring the extent, as well as mechanistic and structural bases, of their substrate promiscuity. We expressed and purified 11 enzymes from seven subgroups of the flavin/deazaflavin oxidoreductase (FDOR) superfamily (A1, A2, A3, B1, B2, B3, B4) from the model soil actinobacterium Mycobacterium smegmatis. These enzymes reduced compounds from six chemical classes, including fundamental monocycles such as a cyclohexenone, a dihydropyran, and pyrones, as well as more complex quinone, coumarin, and arylmethane compounds. Substrate range and reduction rates varied between the enzymes, with the A1, A3, and B1 groups exhibiting greatest promiscuity. Molecular docking studies suggested that structurally diverse compounds are accommodated in the large substrate-binding pocket of the most promiscuous FDOR through hydrophobic interactions with conserved aromatic residues and the isoalloxazine headgroup of F420H2. Liquid chromatography-mass spectrometry (LC/MS) and gas chromatography-mass spectrometry (GC/MS) analysis of derivatized reaction products showed reduction occurred through a common mechanism involving hydride transfer from F420H- to the electron-deficient alkene groups of substrates. Reduction occurs when the hydride donor (C5 of F420H-) is proximal to the acceptor (electrophilic alkene of the substrate). These findings suggest that engineered actinobacterial F420H2-dependent reductases are promising novel biocatalysts for the facile transformation of a wide range of α,β-unsaturated compounds.
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Affiliation(s)
- Chris Greening
- Land and Water Flagship, The Commonwealth Scientific and Industrial Research Organisation, ActonACT, Australia.,School of Biological Sciences, Monash University, ClaytonVIC, Australia
| | - Thanavit Jirapanjawat
- Land and Water Flagship, The Commonwealth Scientific and Industrial Research Organisation, ActonACT, Australia.,School of Biological Sciences, Monash University, ClaytonVIC, Australia.,Research School of Chemistry, Australian National University, ActonACT, Australia
| | - Shahana Afroze
- Land and Water Flagship, The Commonwealth Scientific and Industrial Research Organisation, ActonACT, Australia.,Research School of Chemistry, Australian National University, ActonACT, Australia
| | - Blair Ney
- Land and Water Flagship, The Commonwealth Scientific and Industrial Research Organisation, ActonACT, Australia.,School of Biological Sciences, Monash University, ClaytonVIC, Australia.,Research School of Chemistry, Australian National University, ActonACT, Australia
| | - Colin Scott
- Land and Water Flagship, The Commonwealth Scientific and Industrial Research Organisation, ActonACT, Australia
| | - Gunjan Pandey
- Land and Water Flagship, The Commonwealth Scientific and Industrial Research Organisation, ActonACT, Australia
| | - Brendon M Lee
- Land and Water Flagship, The Commonwealth Scientific and Industrial Research Organisation, ActonACT, Australia.,Research School of Chemistry, Australian National University, ActonACT, Australia
| | - Robyn J Russell
- Land and Water Flagship, The Commonwealth Scientific and Industrial Research Organisation, ActonACT, Australia
| | - Colin J Jackson
- Research School of Chemistry, Australian National University, ActonACT, Australia
| | - John G Oakeshott
- Land and Water Flagship, The Commonwealth Scientific and Industrial Research Organisation, ActonACT, Australia
| | - Matthew C Taylor
- Land and Water Flagship, The Commonwealth Scientific and Industrial Research Organisation, ActonACT, Australia
| | - Andrew C Warden
- Land and Water Flagship, The Commonwealth Scientific and Industrial Research Organisation, ActonACT, Australia
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21
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Chu WT, Nesbitt NM, Gnatenko DV, Li Z, Zhang B, Seeliger MA, Browne S, Mantle TJ, Bahou WF, Wang J. Enzymatic Activity and Thermodynamic Stability of Biliverdin IXβ Reductase Are Maintained by an Active Site Serine. Chemistry 2017; 23:1891-1900. [PMID: 27897348 DOI: 10.1002/chem.201604517] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Indexed: 11/10/2022]
Abstract
Biliverdin reductase IXβ (BLVRB) is a crucial enzyme in heme metabolism. Recent studies in humans have identified a loss-of-function mutation (Ser111Leu) that unmasks a fundamentally important role in hematopoiesis. We have undertaken experimental and thermodynamic modeling studies to provide further insight into the role of the cofactor in substrate accessibility and protein folding properties regulating BLVRB catalytic mechanisms. Site-directed mutagenesis with molecular dynamic (MD) simulations establish the critical role of NAD(P)H-dependent conformational changes on substrate accessibility by forming the "hydrophobic pocket", along with identification of a single key residue (Arg35) modulating NADPH/NADH selectivity. Loop80 and Loop120 block the hydrophobic substrate binding pocket in apo BLVRB (open), whereas movement of these structures after cofactor binding results in the "closed" (catalytically active) conformation. Both enzymatic activity and thermodynamic stability are affected by mutation(s) involving Ser111, which is located in the core of the BLVRB active site. This work 1) elucidates the crucial role of Ser111 in enzymatic catalysis and thermodynamic stability by active site hydrogen bond network; 2) defines a dynamic model for apo BLVRB extending beyond the crystal structure of the binary BLVRB/NADP+ complex; 3) provides a structural basis for the "encounter" and "equilibrium" states of the binary complex, which are regulated by NAD(P)H.
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Affiliation(s)
- Wen-Ting Chu
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, 130022, P. R. China
| | - Natasha M Nesbitt
- Department of Medicine, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Dmitri V Gnatenko
- Department of Medicine, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Zongdong Li
- Department of Medicine, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Beibei Zhang
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Markus A Seeliger
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Seamus Browne
- Department of Biochemistry, Trinity College, Dublin 2, Ireland
| | | | - Wadie F Bahou
- Department of Medicine, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Jin Wang
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, 130022, P. R. China.,Department of Chemistry and Physics, Stony Brook University, Stony Brook, NY, 11794, USA
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22
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Mohamed AE, Condic-Jurkic K, Ahmed FH, Yuan P, O'Mara ML, Jackson CJ, Coote ML. Hydrophobic Shielding Drives Catalysis of Hydride Transfer in a Family of F 420H 2-Dependent Enzymes. Biochemistry 2016; 55:6908-6918. [PMID: 27951661 DOI: 10.1021/acs.biochem.6b00683] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A family of flavin/deazaflavin-dependent oxidoreductases (FDORs) from mycobacteria has been recently characterized and found to play a variety of catalytic roles, including the activation of prodrugs such as the candidate anti-tuberculosis drug pretomanid (PA-824). However, our understanding of the catalytic mechanism used by these enzymes is relatively limited. To address this, we have used a combination of quantum mechanics and molecular dynamics calculations to study the catalytic mechanism of the activation of pretomanid by the deazaflavin-dependent nitroreductase (Ddn) from Mycobacterium tuberculosis. The preferred pathway involves an initial hydride transfer step from the deprotonated cofactor (i.e., F420H-), with subsequent protonation, before a series of spontaneous intramolecular reactions to form the final reactive nitrogen species. The most likely proton source is a hydroxonium ion within the solvent accessible active site. Intriguingly, catalysis of the rate-determining hydride transfer step is aided by three tyrosine residues that form a hydrophobic barrier around the active site that, upon reaction, is then disrupted to allow increased water accessibility to facilitate the subsequent proton transfer step. The catalytic mechanism we propose is consistent with previous experimental observations of the Ddn enzyme and will inform the design of improved prodrugs in the future.
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Affiliation(s)
- A Elaaf Mohamed
- Research School of Chemistry, Australian National University , Canberra, ACT 2601, Australia
| | - Karmen Condic-Jurkic
- Research School of Chemistry, Australian National University , Canberra, ACT 2601, Australia
| | - F Hafna Ahmed
- Research School of Chemistry, Australian National University , Canberra, ACT 2601, Australia
| | - Peng Yuan
- Research School of Chemistry, Australian National University , Canberra, ACT 2601, Australia
| | - Megan L O'Mara
- Research School of Chemistry, Australian National University , Canberra, ACT 2601, Australia
| | - Colin J Jackson
- Research School of Chemistry, Australian National University , Canberra, ACT 2601, Australia
| | - Michelle L Coote
- ARC Centre of Excellence for Electromaterials Science, Research School of Chemistry, Australian National University , Canberra, ACT 2601, Australia
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23
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Recent advancements in the development of anti-tuberculosis drugs. Bioorg Med Chem Lett 2016; 27:370-386. [PMID: 28017531 DOI: 10.1016/j.bmcl.2016.11.084] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 11/16/2016] [Accepted: 11/27/2016] [Indexed: 01/09/2023]
Abstract
Modern chemotherapy has significantly improved patient outcomes against drug-sensitive tuberculosis. However, the rapid emergence of drug-resistant tuberculosis, together with the bacterium's ability to persist and remain latent present a major public health challenge. To overcome this problem, research into novel anti-tuberculosis targets and drug candidates is thus of paramount importance. This review article provides an overview of tuberculosis highlighting the recent advances and tools that are employed in the field of anti-tuberculosis drug discovery. The predominant focus is on anti-tuberculosis agents that are currently in the pipeline, i.e. clinical trials.
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24
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The Redox Cofactor F 420 Protects Mycobacteria from Diverse Antimicrobial Compounds and Mediates a Reductive Detoxification System. Appl Environ Microbiol 2016; 82:6810-6818. [PMID: 27637879 DOI: 10.1128/aem.02500-16] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 09/06/2016] [Indexed: 01/25/2023] Open
Abstract
A defining feature of mycobacterial redox metabolism is the use of an unusual deazaflavin cofactor, F420 This cofactor enhances the persistence of environmental and pathogenic mycobacteria, including after antimicrobial treatment, although the molecular basis for this remains to be understood. In this work, we explored our hypothesis that F420 enhances persistence by serving as a cofactor in antimicrobial-detoxifying enzymes. To test this, we performed a series of phenotypic, biochemical, and analytical chemistry studies in relation to the model soil bacterium Mycobacterium smegmatis Mutant strains unable to synthesize or reduce F420 were found to be more susceptible to a wide range of antibiotic and xenobiotic compounds. Compounds from three classes of antimicrobial compounds traditionally resisted by mycobacteria inhibited the growth of F420 mutant strains at subnanomolar concentrations, namely, furanocoumarins (e.g., methoxsalen), arylmethanes (e.g., malachite green), and quinone analogues (e.g., menadione). We demonstrated that promiscuous F420H2-dependent reductases directly reduce these compounds by a mechanism consistent with hydride transfer. Moreover, M. smegmatis strains unable to make F420H2 lost the capacity to reduce and detoxify representatives of the furanocoumarin and arylmethane compound classes in whole-cell assays. In contrast, mutant strains were only slightly more susceptible to clinical antimycobacterials, and this appeared to be due to indirect effects of F420 loss of function (e.g., redox imbalance) rather than loss of a detoxification system. Together, these data show that F420 enhances antimicrobial resistance in mycobacteria and suggest that one function of the F420H2-dependent reductases is to broaden the range of natural products that mycobacteria and possibly other environmental actinobacteria can reductively detoxify.IMPORTANCE This study reveals that a unique microbial cofactor, F420, is critical for antimicrobial resistance in the environmental actinobacterium Mycobacterium smegmatis We show that a superfamily of redox enzymes, the F420H2-dependent reductases, can reduce diverse antimicrobials in vitro and in vivoM. smegmatis strains unable to make or reduce F420 become sensitive to inhibition by these antimicrobial compounds. This suggests that mycobacteria have harnessed the unique properties of F420 to reduce structurally diverse antimicrobials as part of the antibiotic arms race. The F420H2-dependent reductases that facilitate this process represent a new class of antimicrobial-detoxifying enzymes with potential applications in bioremediation and biocatalysis.
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