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Giang PD, Churchman LR, Buczynski JB, Bell SG, Stok JE, De Voss JJ. CYP108N14: A Monoterpene Monooxygenase from Rhodococcus globerulus. Arch Biochem Biophys 2024; 752:109852. [PMID: 38072297 DOI: 10.1016/j.abb.2023.109852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 12/04/2023] [Accepted: 12/05/2023] [Indexed: 01/29/2024]
Abstract
Rhodococcus globerulus (R. globerulus) was isolated from the soil beneath a Eucalypt tree. Metabolic growth studies revealed that R. globerulus was capable of living on certain monoterpenes, including 1,8-cineole and p-cymene, as sole sources of carbon and energy. Multiple P450 genes were identified in the R. globerulus genome that shared homology to known bacterial, monoterpene hydroxylating P450s. To date, two of these P450s have been expressed and characterised as 1,8-cineole (CYP176A1) and p-cymene (CYP108N12) monooxygenases that are believed to initiate the biodegradation of these terpenes. In this work, another putative P450 gene (CYP108N14) was identified in R. globerulus genome. Given its amino acid sequence identity to other monoterpene hydroxylating P450s it was hypothesised to catalyse monoterpene hydroxylation. These include CYP108A1 from Pseudomonas sp. (47 % identity, 68 % similarity) which hydroxylates α-terpineol, and CYP108N12 also from R. globerulus (62 % identity, 77 % similarity). Also present in the operon containing CYP108N14 were putative ferredoxin and ferredoxin reductase genes, suggesting a typical Class I P450 system. CYP108N14 was successfully over-expressed heterologously and purified, resulting in a good yield of CYP108N14 holoprotein. However, neither the ferredoxin nor ferredoxin reductase could be produced heterologously. Binding studies with CYP108N14 revealed a preference for the monoterpenes p-cymene, (R)-limonene, (S)-limonene, (S)-α-terpineol and (S)-4-terpineol. An active catalytic system was reconstituted with the non-native redox partners cymredoxin (from the CYP108N12 system) and putidaredoxin reductase (from the CYP101A1 system). CYP108N14 when supported by these redox partners was able to catalyse the hydroxylation of the five aforementioned substrates selectively at the methyl benzylic/allylic positions.
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Affiliation(s)
- Peter D Giang
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Brisbane, Australia
| | - Luke R Churchman
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Brisbane, Australia
| | - Julia B Buczynski
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Brisbane, Australia
| | - Stephen G Bell
- Department of Chemistry, University of Adelaide, Adelaide, SA, 5005, Australia
| | - Jeanette E Stok
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Brisbane, Australia
| | - James J De Voss
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Brisbane, Australia.
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Churchman LR, Giang PD, Buczynski JB, Stok JE, Bell SG, De Voss JJ. Synthesis of substituted norcaranes for use as probes of enzyme mechanisms. Org Biomol Chem 2023; 21:9647-9658. [PMID: 38037692 DOI: 10.1039/d3ob01571h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
Norcarane is a mechanistic probe of monooxygenase enzymes that is able to detect the presence of cationic or radical intermediates. The addition of substituents around the bicycloheptane ring of the norcarane scaffold can assist in improving enzyme binding affinity and thus improve the regioselectivity of oxidation. Here we prepare in three-step, diastereoselective syntheses, ten norcaranes monosubstituted α to the cyclopropane as advanced probes. Four of these compounds were examined in enzyme binding experiments to evaluate their potential as probe substrates. Additionally, 19 potential products of enzymatic oxidation were generated via two additional synthetic steps for use as product standards in future studies.
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Affiliation(s)
- Luke R Churchman
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Brisbane, Queensland, 4072, Australia.
| | - Peter D Giang
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Brisbane, Queensland, 4072, Australia.
| | - Julia B Buczynski
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Brisbane, Queensland, 4072, Australia.
| | - Jeanette E Stok
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Brisbane, Queensland, 4072, Australia.
| | - Stephen G Bell
- Department of Chemistry, University of Adelaide, Adelaide, South Australia, 5005, Australia
| | - James J De Voss
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Brisbane, Queensland, 4072, Australia.
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Salisbury LJ, Fletcher SJ, Stok JE, Churchman LR, Blanchfield JT, De Voss JJ. Characterization of the cholesterol biosynthetic pathway in Dioscorea transversa. J Biol Chem 2023:104768. [PMID: 37142228 DOI: 10.1016/j.jbc.2023.104768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 04/24/2023] [Accepted: 04/25/2023] [Indexed: 05/06/2023] Open
Abstract
Cholesterol is the precursor of bioactive plant metabolites such as steroidal saponins. An Australian plant, Dioscorea transversa, produces only two steroidal saponins: 1β-hydroxyprotoneogracillin and protoneogracillin. Here, we used D. transversa as a model in which to elucidate the biosynthetic pathway to cholesterol, a precursor to these compounds. Preliminary transcriptomes of D. transversa rhizome and leaves were constructed, annotated, and analyzed. We identified a novel sterol side chain reductase (SSR) as a key initiator of cholesterol biosynthesis in this plant. By complementation in yeast, we determine that this SSR reduces Δ24,28 double bonds required for phytosterol biogenesis, as well as Δ24,25 double bonds. The latter function is believed to initiate cholesterogenesis by reducing cycloartenol to cycloartanol. Through heterologous expression, purification and enzymatic reconstitution we also demonstrate that the D. transversa sterol demethylase (CYP51) effectively demethylates obtusifoliol, an intermediate of phytosterol biosynthesis and 4-desmethyl-24,25-dihydrolanosterol, a postulated downstream intermediate of cholesterol biosynthesis. In summary, we investigated specific steps of the cholesterol biosynthetic pathway, providing further insight into the downstream production of bioactive steroidal saponin metabolites.
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Giang PD, Churchman LR, Stok JE, Bell SG, De Voss JJ. Cymredoxin, a [2Fe-2S] ferredoxin, supports catalytic activity of the p-cymene oxidising P450 enzyme CYP108N12. Arch Biochem Biophys 2023; 737:109549. [PMID: 36801262 DOI: 10.1016/j.abb.2023.109549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 02/07/2023] [Accepted: 02/12/2023] [Indexed: 02/18/2023]
Abstract
Rhodococcus globerulus is a metabolically active organism that has been shown to utilise eucalypt oil as its sole source of carbon and energy. This oil includes 1,8-cineole, p-cymene and limonene. Two identified and characterised cytochromes P450 (P450s) from this organism initiate the biodegradation of the monoterpenes 1,8-cineole (CYP176A1) and p-cymene (CYP108N12). Extensive characterisation has been completed for CYP176A1 and it has been successfully reconstituted with its immediate redox partner, cindoxin, and E. coli flavodoxin reductase. Two putative redox partner genes are encoded in the same operon as CYP108N12 and here the isolation, expression, purification, and characterisation of its specific [2Fe-2S] ferredoxin redox partner, cymredoxin is presented. Reconstitution of CYP108N12 with cymredoxin in place of putidaredoxin, a [2Fe-2S] redox partner of another P450, improves both the rate of electron transfer (from 13 ± 2 to 70 ± 1 μM NADH/min/μM CYP108N12) and the efficiency of NADH utilisation (the so-called coupling efficiency increases from 13% to 90%). Cymredoxin improves the catalytic ability of CYP108N12 in vitro. Aldehyde oxidation products of the previously identified substrates p-cymene (4-isopropylbenzaldehyde) and limonene (perillaldehyde) were observed in addition to major hydroxylation products 4-isopropylbenzyl alcohol and perillyl alcohol respectively. These further oxidation products had not previously been seen with putidaredoxin supported oxidation. Furthermore, when supported by cymredoxin CYP108N12 is able to oxidise a wider range of substrates than previously reported. These include o-xylene, α-terpineol, (-)-carveol and thymol yielding o-tolylmethanol, 7-hydroxyterpineol, (4R)-7-hydroxycarveol and 5-hydroxymethyl-2-isopropylphenol, respectively. Cymredoxin is also capable of supporting CYP108A1 (P450terp) and CYP176A1 activity, allowing them to catalyse the hydroxylation of their native substrates α-terpineol to 7-hydroxyterpineol and 1,8-cineole to 6β-hydroxycineole respectively. These results indicate that cymredoxin not only improves the catalytic capability of CYP108N12 but can also support the activity of other P450s and prove useful for their characterisation.
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Affiliation(s)
- Peter D Giang
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, 4067, Australia
| | - Luke R Churchman
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, 4067, Australia
| | - Jeanette E Stok
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, 4067, Australia
| | - Stephen G Bell
- Department of Chemistry, University of Adelaide, Adelaide, SA, 5005, Australia
| | - James J De Voss
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, 4067, Australia.
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Coleman T, Stok JE, Podgorski MN, Bruning JB, De Voss JJ, Bell SG. Structural insights into the role of the acid-alcohol pair of residues required for dioxygen activation in cytochrome P450 enzymes. J Biol Inorg Chem 2020; 25:583-596. [PMID: 32248305 DOI: 10.1007/s00775-020-01781-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 03/22/2020] [Indexed: 10/24/2022]
Abstract
The cytochrome P450 heme monooxygenases commonly use an acid-alcohol pair of residues, within the I-helix, to activate iron-bound dioxygen. This work aims to clarify conflicting reports on the importance of the alcohol functionality in this process. Mutants of the P450, CYP199A4 (CYP199A4D251N and CYP199A4T252A), were prepared, characterised and their crystal structures were solved. The acid residue of CYP199A4 is not part of a salt bridge network, a key feature of paradigmatic model system P450cam. Instead, there is a direct proton delivery network, via a chain of water molecules, extending to the surface. Nevertheless, CYP199A4D251N dramatically reduced the activity of the enzyme consistent with a role in proton delivery. CYP199A4T252A decreased the coupling efficiency of the enzyme with a concomitant increase in the hydrogen peroxide uncoupling pathway. However, the effect of this mutation was much less pronounced than reported with P450cam. Its crystal structures revealed fewer changes at the I-helix, compared to the P450cam system. The structural changes observed within the I-helix of P450cam during oxygen activation do not seem to be required in this P450. These differences are due to the presence of a second threonine residue at position 253, which is absent in P450cam. This threonine forms part of the hydrogen bonding network, resulting in subtle structural changes and is also present across the majority of the P450 superfamily. Overall, the results suggest that while the acid-alcohol pair is important for dioxygen activation this process and the method of proton delivery can differ across P450s.Graphic abstract.
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Affiliation(s)
- Tom Coleman
- Department of Chemistry, University of Adelaide, Adelaide, SA, 5005, Australia
| | - Jeanette E Stok
- School of Chemistry and Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Matthew N Podgorski
- Department of Chemistry, University of Adelaide, Adelaide, SA, 5005, Australia
| | - John B Bruning
- School of Biological Sciences, University of Adelaide, Adelaide, SA, 5005, Australia
| | - James J De Voss
- School of Chemistry and Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Stephen G Bell
- Department of Chemistry, University of Adelaide, Adelaide, SA, 5005, Australia.
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Podgorski MN, Harbort JS, Coleman T, Stok JE, Yorke JA, Wong LL, Bruning JB, Bernhardt PV, De Voss JJ, Harmer JR, Bell SG. Biophysical Techniques for Distinguishing Ligand Binding Modes in Cytochrome P450 Monooxygenases. Biochemistry 2020; 59:1038-1050. [PMID: 32058707 DOI: 10.1021/acs.biochem.0c00027] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The cytochrome P450 superfamily of heme monooxygenases catalyzes important chemical reactions across nature. The changes in the optical spectra of these enzymes, induced by the addition of substrates or inhibitors, are critical for assessing how these molecules bind to the P450, enhancing or inhibiting the catalytic cycle. Here we use the bacterial CYP199A4 enzyme (Uniprot entry Q2IUO2), from Rhodopseudomonas palustris HaA2, and a range of substituted benzoic acids to investigate different binding modes. 4-Methoxybenzoic acid elicits an archetypal type I spectral response due to a ≥95% switch from the low- to high-spin state with concomitant dissociation of the sixth aqua ligand. 4-(Pyridin-3-yl)- and 4-(pyridin-2-yl)benzoic acid induced different type II ultraviolet-visible (UV-vis) spectral responses in CYP199A4. The former induced a greater red shift in the Soret wavelength (424 nm vs 422 nm) along with a larger overall absorbance change and other differences in the α-, β-, and δ-bands. There were also variations in the ferrous UV-vis spectra of these two substrate-bound forms with a spectrum indicative of Fe-N bond formation with 4-(pyridin-3-yl)benzoic acid. The crystal structures of CYP199A4, with the pyridinyl compounds bound, revealed that while the nitrogen of 4-(pyridin-3-yl)benzoic acid is coordinated to the heme, with 4-(pyridin-2-yl)benzoic acid an aqua ligand remains. Continuous wave and pulse electron paramagnetic resonance data in frozen solution revealed that the substrates are bound in the active site in a form consistent with the crystal structures. The redox potential of each CYP199A4-substrate combination was measured, allowing correlation among binding modes, spectroscopic properties, and the observed biochemical activity.
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Affiliation(s)
- Matthew N Podgorski
- Department of Chemistry, University of Adelaide, Adelaide, SA 5005, Australia
| | - Joshua S Harbort
- Center for Advanced Imaging, University of Queensland, Brisbane, QLD 4072, Australia
| | - Tom Coleman
- Department of Chemistry, University of Adelaide, Adelaide, SA 5005, Australia
| | - Jeanette E Stok
- School of Chemistry and Molecular Bioscience, University of Queensland, Brisbane, QLD 4072, Australia
| | - Jake A Yorke
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - Luet-Lok Wong
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - John B Bruning
- School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Bioscience, University of Queensland, Brisbane, QLD 4072, Australia
| | - James J De Voss
- School of Chemistry and Molecular Bioscience, University of Queensland, Brisbane, QLD 4072, Australia
| | - Jeffrey R Harmer
- Center for Advanced Imaging, University of Queensland, Brisbane, QLD 4072, Australia
| | - Stephen G Bell
- Department of Chemistry, University of Adelaide, Adelaide, SA 5005, Australia
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Houston SD, Fahrenhorst-Jones T, Xing H, Chalmers BA, Sykes ML, Stok JE, Farfan Soto C, Burns JM, Bernhardt PV, De Voss JJ, Boyle GM, Smith MT, Tsanaktsidis J, Savage GP, Avery VM, Williams CM. The cubane paradigm in bioactive molecule discovery: further scope, limitations and the cyclooctatetraene complement. Org Biomol Chem 2020; 17:6790-6798. [PMID: 31241113 DOI: 10.1039/c9ob01238a] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The cubane phenyl ring bioisostere paradigm was further explored in an extensive study covering a wide range of pharmaceutical and agrochemical templates, which included antibiotics (cefaclor, penicillin G) and antihistamine (diphenhydramine), a smooth muscle relaxant (alverine), an anaesthetic (ketamine), an agrochemical instecticide (triflumuron), an antiparasitic (benznidazole) and an anticancer agent (tamibarotene). This investigation highlights the scope and limitations of incorporating cubane into bioactive molecule discovery, both in terms of synthetic compatibility and physical property matching. Cubane maintained bioisosterism in the case of the Chagas disease antiparasitic benznidazole, although it was less active in the case of the anticancer agent (tamibarotenne). Application of the cyclooctatetraene (COT) (bio)motif complement was found to optimize benznidazole relative to the benzene parent, and augmented anticancer activity relative to the cubane analogue in the case of tamibarotene. Like all bioisosteres, scaffolds and biomotifs, however, there are limitations (e.g. synthetic implementation), and these have been specifically highlighted herein using failed examples. A summary of all templates prepared to date by our group that were biologically evaluated strongly supports the concept that cubane is a valuable tool in bioactive molecule discovery and COT is a viable complement.
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Affiliation(s)
- Sevan D Houston
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD), Australia.
| | - Tyler Fahrenhorst-Jones
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD), Australia.
| | - Hui Xing
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD), Australia.
| | - Benjamin A Chalmers
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD), Australia.
| | - Melissa L Sykes
- Discovery Biology, Griffith Institute for Drug Discovery, Griffith University, Brisbane, QLD 4111, Australia
| | - Jeanette E Stok
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD), Australia.
| | - Clementina Farfan Soto
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD), Australia.
| | - Jed M Burns
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD), Australia.
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD), Australia.
| | - James J De Voss
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD), Australia.
| | - Glen M Boyle
- QIMR Berghofer Medical Research Institute, PO Royal Brisbane Hospital, Brisbane, 4029, QLD, Australia
| | - Maree T Smith
- School of Biomedical Sciences, Faculty of Medicine, UQ, Brisbane, Australia
| | - John Tsanaktsidis
- CSIRO Manufacturing, Ian Wark Laboratory, Melbourne, 3168, Victoria (VIC), Australia
| | - G Paul Savage
- CSIRO Manufacturing, Ian Wark Laboratory, Melbourne, 3168, Victoria (VIC), Australia
| | - Vicky M Avery
- Discovery Biology, Griffith Institute for Drug Discovery, Griffith University, Brisbane, QLD 4111, Australia
| | - Craig M Williams
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD), Australia.
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Greule A, Stok JE, De Voss JJ, Cryle MJ. Unrivalled diversity: the many roles and reactions of bacterial cytochromes P450 in secondary metabolism. Nat Prod Rep 2019; 35:757-791. [PMID: 29667657 DOI: 10.1039/c7np00063d] [Citation(s) in RCA: 137] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Covering: 2000 up to 2018 The cytochromes P450 (P450s) are a superfamily of heme-containing monooxygenases that perform diverse catalytic roles in many species, including bacteria. The P450 superfamily is widely known for the hydroxylation of unactivated C-H bonds, but the diversity of reactions that P450s can perform vastly exceeds this undoubtedly impressive chemical transformation. Within bacteria, P450s play important roles in many biosynthetic and biodegradative processes that span a wide range of secondary metabolite pathways and present diverse chemical transformations. In this review, we aim to provide an overview of the range of chemical transformations that P450 enzymes can catalyse within bacterial secondary metabolism, with the intention to provide an important resource to aid in understanding of the potential roles of P450 enzymes within newly identified bacterial biosynthetic pathways.
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Affiliation(s)
- Anja Greule
- The Monash Biomedicine Discovery Institute, Department of Biochemistry and Molecular Biology, ARC Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia. and EMBL Australia, Monash University, Clayton, Victoria 3800, Australia
| | - Jeanette E Stok
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia.
| | - James J De Voss
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia.
| | - Max J Cryle
- The Monash Biomedicine Discovery Institute, Department of Biochemistry and Molecular Biology, ARC Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia. and EMBL Australia, Monash University, Clayton, Victoria 3800, Australia and Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany.
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Stok JE, Giang PD, Wong SH, De Voss JJ. Exploring the substrate specificity of Cytochrome P450 cin. Arch Biochem Biophys 2019; 672:108060. [PMID: 31356780 DOI: 10.1016/j.abb.2019.07.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 07/25/2019] [Accepted: 07/25/2019] [Indexed: 11/25/2022]
Abstract
Cytochromes P450 are enzymes that catalyse the oxidation of a wide variety of compounds that range from small volatile compounds, such as monoterpenes to larger compounds like steroids. These enzymes can be modified to selectively oxidise substrates of interest, thereby making them attractive for applications in the biotechnology industry. In this study, we screened a small library of terpenes and terpenoid compounds against P450cin and two P450cin mutants, N242A and N242T, that have previously been shown to affect selectivity. Initial screening indicated that P450cin could catalyse the oxidation of most of the monoterpenes tested; however, sesquiterpenes were not substrates for this enzyme or the N242A mutant. Additionally, both P450cin mutants were found to be able to oxidise other bicyclic monoterpenes. For example, the oxidation of (R)- and (S)-camphor by N242T favoured the production of 5-endo-hydroxycamphor (65-77% of the total products, dependent on the enantiomer), which was similar to that previously observed for (R)-camphor with N242A (73%). Selectivity was also observed for both (R)- and (S)-limonene where N242A predominantly produced the cis-limonene 1,2-epoxide (80% of the products following (R)-limonene oxidation) as compared to P450cin (23% of the total products with (R)-limonene). Of the three enzymes screened, only P450cin was observed to catalyse the oxidation of the aromatic terpene p-cymene. All six possible hydroxylation products were generated from an in vivo expression system catalysing the oxidation of p-cymene and were assigned based on 1H NMR and GC-MS fragmentation patterns. Overall, these results have provided the foundation for pursuing new P450cin mutants that can selectively oxidise various monoterpenes for biocatalytic applications.
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Affiliation(s)
- Jeanette E Stok
- School of Chemistry and Molecular Biosciences, The University of Queensland, Australia
| | - Peter D Giang
- School of Chemistry and Molecular Biosciences, The University of Queensland, Australia
| | - Siew Hoon Wong
- School of Chemistry and Molecular Biosciences, The University of Queensland, Australia
| | - James J De Voss
- School of Chemistry and Molecular Biosciences, The University of Queensland, Australia.
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Slessor KE, Stok JE, Chow S, De Voss JJ. Significance of Protein–Substrate Hydrogen Bonding for the Selectivity of P450‐Catalysed Oxidations. Chemistry 2019; 25:4149-4155. [DOI: 10.1002/chem.201805705] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Indexed: 11/08/2022]
Affiliation(s)
- Kate E. Slessor
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane 4072 Australia
| | - Jeanette E. Stok
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane 4072 Australia
| | - Sharon Chow
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane 4072 Australia
| | - James J. De Voss
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane 4072 Australia
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Chalmers BA, Xing H, Houston S, Clark C, Ghassabian S, Kuo A, Cao B, Reitsma A, Murray CP, Stok JE, Boyle GM, Pierce CJ, Littler SW, Winkler DA, Bernhardt PV, Pasay C, De Voss JJ, McCarthy J, Parsons PG, Walter GH, Smith MT, Cooper HM, Nilsson SK, Tsanaktsidis J, Savage GP, Williams CM. Corrigendum: Validating Eaton's Hypothesis: Cubane as a Benzene Bioisostere. Angew Chem Int Ed Engl 2018; 57:8359. [DOI: 10.1002/anie.201711161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Chalmers BA, Xing H, Houston S, Clark C, Ghassabian S, Kuo A, Cao B, Reitsma A, Murray CP, Stok JE, Boyle GM, Pierce CJ, Littler SW, Winkler DA, Bernhardt PV, Pasay C, De Voss JJ, McCarthy J, Parsons PG, Walter GH, Smith MT, Cooper HM, Nilsson SK, Tsanaktsidis J, Savage GP, Williams CM. Berichtigung: Validating Eaton's Hypothesis: Cubane as a Benzene Bioisostere. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201711161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Stok JE, Hall EA, Stone IS, Noble MC, Wong SH, Bell SG, De Voss JJ. In vivo and in vitro hydroxylation of cineole and camphor by cytochromes P450CYP101A1, CYP101B1 and N242A CYP176A1. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.molcatb.2016.03.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Chalmers BA, Xing H, Houston S, Clark C, Ghassabian S, Kuo A, Cao B, Reitsma A, Murray CEP, Stok JE, Boyle GM, Pierce CJ, Littler SW, Winkler DA, Bernhardt PV, Pasay C, De Voss JJ, McCarthy J, Parsons PG, Walter GH, Smith MT, Cooper HM, Nilsson SK, Tsanaktsidis J, Savage GP, Williams CM. Frontispiece: Validating Eaton's Hypothesis: Cubane as a Benzene Bioisostere. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/anie.201681161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Benjamin A. Chalmers
- School of Chemistry and Molecular Biosciences; University of Queensland (UQ); Brisbane 4072 Queensland (QLD Australia
| | - Hui Xing
- School of Chemistry and Molecular Biosciences; University of Queensland (UQ); Brisbane 4072 Queensland (QLD Australia
| | - Sevan Houston
- School of Chemistry and Molecular Biosciences; University of Queensland (UQ); Brisbane 4072 Queensland (QLD Australia
| | | | | | - Andy Kuo
- Centre for Integrated Preclinical Drug Development, UQ; Australia
| | - Benjamin Cao
- CISRO Manufacturing; Ian Wark Laboratory; Melbourne 3168 Victoria (VIC Australia
- Australian Regenerative Medicine Institute; Monash University (MU); Melbourne 3168 VIC Australia
| | - Andrea Reitsma
- CISRO Manufacturing; Ian Wark Laboratory; Melbourne 3168 Victoria (VIC Australia
- Australian Regenerative Medicine Institute; Monash University (MU); Melbourne 3168 VIC Australia
| | | | - Jeanette E. Stok
- School of Chemistry and Molecular Biosciences; University of Queensland (UQ); Brisbane 4072 Queensland (QLD Australia
| | - Glen M. Boyle
- QIMR Berghofer Medical Research Institute; PO Royal Brisbane Hospital Brisbane 4029 QLD Australia
| | - Carly J. Pierce
- QIMR Berghofer Medical Research Institute; PO Royal Brisbane Hospital Brisbane 4029 QLD Australia
| | - Stuart W. Littler
- CISRO Manufacturing; Ian Wark Laboratory; Melbourne 3168 Victoria (VIC Australia
| | - David A. Winkler
- CISRO Manufacturing; Ian Wark Laboratory; Melbourne 3168 Victoria (VIC Australia
- Monash Institute of Pharmaceutical Sciences; Parkville 3052 MU Australia
| | - Paul V. Bernhardt
- School of Chemistry and Molecular Biosciences; University of Queensland (UQ); Brisbane 4072 Queensland (QLD Australia
| | - Cielo Pasay
- QIMR Berghofer Medical Research Institute; PO Royal Brisbane Hospital Brisbane 4029 QLD Australia
| | - James J. De Voss
- School of Chemistry and Molecular Biosciences; University of Queensland (UQ); Brisbane 4072 Queensland (QLD Australia
| | - James McCarthy
- QIMR Berghofer Medical Research Institute; PO Royal Brisbane Hospital Brisbane 4029 QLD Australia
- Australian Centre for International and Tropical Health, UQ; Australia
| | - Peter G. Parsons
- QIMR Berghofer Medical Research Institute; PO Royal Brisbane Hospital Brisbane 4029 QLD Australia
| | | | - Maree T. Smith
- Centre for Integrated Preclinical Drug Development, UQ; Australia
| | | | - Susan K. Nilsson
- CISRO Manufacturing; Ian Wark Laboratory; Melbourne 3168 Victoria (VIC Australia
- Australian Regenerative Medicine Institute; Monash University (MU); Melbourne 3168 VIC Australia
| | - John Tsanaktsidis
- CISRO Manufacturing; Ian Wark Laboratory; Melbourne 3168 Victoria (VIC Australia
| | - G. Paul Savage
- CISRO Manufacturing; Ian Wark Laboratory; Melbourne 3168 Victoria (VIC Australia
| | - Craig M. Williams
- School of Chemistry and Molecular Biosciences; University of Queensland (UQ); Brisbane 4072 Queensland (QLD Australia
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15
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Chalmers BA, Xing H, Houston S, Clark C, Ghassabian S, Kuo A, Cao B, Reitsma A, Murray CEP, Stok JE, Boyle GM, Pierce CJ, Littler SW, Winkler DA, Bernhardt PV, Pasay C, De Voss JJ, McCarthy J, Parsons PG, Walter GH, Smith MT, Cooper HM, Nilsson SK, Tsanaktsidis J, Savage GP, Williams CM. Frontispiz: Validating Eaton's Hypothesis: Cubane as a Benzene Bioisostere. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201681161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Benjamin A. Chalmers
- School of Chemistry and Molecular Biosciences; University of Queensland (UQ); Brisbane 4072 Queensland (QLD Australia
| | - Hui Xing
- School of Chemistry and Molecular Biosciences; University of Queensland (UQ); Brisbane 4072 Queensland (QLD Australia
| | - Sevan Houston
- School of Chemistry and Molecular Biosciences; University of Queensland (UQ); Brisbane 4072 Queensland (QLD Australia
| | | | | | - Andy Kuo
- Centre for Integrated Preclinical Drug Development, UQ; Australia
| | - Benjamin Cao
- CISRO Manufacturing; Ian Wark Laboratory; Melbourne 3168 Victoria (VIC Australia
- Australian Regenerative Medicine Institute; Monash University (MU); Melbourne 3168 VIC Australia
| | - Andrea Reitsma
- CISRO Manufacturing; Ian Wark Laboratory; Melbourne 3168 Victoria (VIC Australia
- Australian Regenerative Medicine Institute; Monash University (MU); Melbourne 3168 VIC Australia
| | | | - Jeanette E. Stok
- School of Chemistry and Molecular Biosciences; University of Queensland (UQ); Brisbane 4072 Queensland (QLD Australia
| | - Glen M. Boyle
- QIMR Berghofer Medical Research Institute; PO Royal Brisbane Hospital Brisbane 4029 QLD Australia
| | - Carly J. Pierce
- QIMR Berghofer Medical Research Institute; PO Royal Brisbane Hospital Brisbane 4029 QLD Australia
| | - Stuart W. Littler
- CISRO Manufacturing; Ian Wark Laboratory; Melbourne 3168 Victoria (VIC Australia
| | - David A. Winkler
- CISRO Manufacturing; Ian Wark Laboratory; Melbourne 3168 Victoria (VIC Australia
- Monash Institute of Pharmaceutical Sciences; Parkville 3052 MU Australia
| | - Paul V. Bernhardt
- School of Chemistry and Molecular Biosciences; University of Queensland (UQ); Brisbane 4072 Queensland (QLD Australia
| | - Cielo Pasay
- QIMR Berghofer Medical Research Institute; PO Royal Brisbane Hospital Brisbane 4029 QLD Australia
| | - James J. De Voss
- School of Chemistry and Molecular Biosciences; University of Queensland (UQ); Brisbane 4072 Queensland (QLD Australia
| | - James McCarthy
- QIMR Berghofer Medical Research Institute; PO Royal Brisbane Hospital Brisbane 4029 QLD Australia
- Australian Centre for International and Tropical Health, UQ; Australia
| | - Peter G. Parsons
- QIMR Berghofer Medical Research Institute; PO Royal Brisbane Hospital Brisbane 4029 QLD Australia
| | | | - Maree T. Smith
- Centre for Integrated Preclinical Drug Development, UQ; Australia
| | | | - Susan K. Nilsson
- CISRO Manufacturing; Ian Wark Laboratory; Melbourne 3168 Victoria (VIC Australia
- Australian Regenerative Medicine Institute; Monash University (MU); Melbourne 3168 VIC Australia
| | - John Tsanaktsidis
- CISRO Manufacturing; Ian Wark Laboratory; Melbourne 3168 Victoria (VIC Australia
| | - G. Paul Savage
- CISRO Manufacturing; Ian Wark Laboratory; Melbourne 3168 Victoria (VIC Australia
| | - Craig M. Williams
- School of Chemistry and Molecular Biosciences; University of Queensland (UQ); Brisbane 4072 Queensland (QLD Australia
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16
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Stok JE, Chow S, Krenske EH, Farfan Soto C, Matyas C, Poirier RA, Williams CM, De Voss JJ. Direct Observation of an Oxepin from a Bacterial Cytochrome P450‐Catalyzed Oxidation. Chemistry 2016; 22:4408-12. [DOI: 10.1002/chem.201600246] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Jeanette E. Stok
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane Qld 4072 Australia
| | - Sharon Chow
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane Qld 4072 Australia
| | - Elizabeth H. Krenske
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane Qld 4072 Australia
| | - Clementina Farfan Soto
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane Qld 4072 Australia
| | - Csongor Matyas
- Department of Chemistry Memorial University of Newfoundland St. John's NL A1B 3X7 Canada
| | - Raymond A. Poirier
- Department of Chemistry Memorial University of Newfoundland St. John's NL A1B 3X7 Canada
| | - Craig M. Williams
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane Qld 4072 Australia
| | - James J. De Voss
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane Qld 4072 Australia
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17
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Chalmers BA, Xing H, Houston S, Clark C, Ghassabian S, Kuo A, Cao B, Reitsma A, Murray CEP, Stok JE, Boyle GM, Pierce CJ, Littler SW, Winkler DA, Bernhardt PV, Pasay C, De Voss JJ, McCarthy J, Parsons PG, Walter GH, Smith MT, Cooper HM, Nilsson SK, Tsanaktsidis J, Savage GP, Williams CM. Validating Eaton's Hypothesis: Cubane as a Benzene Bioisostere. Angew Chem Int Ed Engl 2016; 55:3580-5. [PMID: 26846616 DOI: 10.1002/anie.201510675] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 01/03/2016] [Indexed: 01/25/2023]
Abstract
Pharmaceutical and agrochemical discovery programs are under considerable pressure to meet increasing global demand and thus require constant innovation. Classical hydrocarbon scaffolds have long assisted in bringing new molecules to the market place, but an obvious omission is that of the Platonic solid cubane. Eaton, however, suggested that this molecule has the potential to act as a benzene bioisostere. Herein, we report the validation of Eaton's hypothesis with cubane derivatives of five molecules that are used clinically or as agrochemicals. Two cubane analogues showed increased bioactivity compared to their benzene counterparts whereas two further analogues displayed equal bioactivity, and the fifth one demonstrated only partial efficacy. Ramifications from this study are best realized by reflecting on the number of bioactive molecules that contain a benzene ring. Substitution with the cubane scaffold where possible could revitalize these systems, and thus expedite much needed lead candidate identification.
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Affiliation(s)
- Benjamin A Chalmers
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD, Australia
| | - Hui Xing
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD, Australia
| | - Sevan Houston
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD, Australia
| | | | | | - Andy Kuo
- Centre for Integrated Preclinical Drug Development, UQ, Australia
| | - Benjamin Cao
- CISRO Manufacturing, Ian Wark Laboratory, Melbourne, 3168, Victoria (VIC, Australia.,Australian Regenerative Medicine Institute, Monash University (MU), Melbourne, 3168, VIC, Australia
| | - Andrea Reitsma
- CISRO Manufacturing, Ian Wark Laboratory, Melbourne, 3168, Victoria (VIC, Australia.,Australian Regenerative Medicine Institute, Monash University (MU), Melbourne, 3168, VIC, Australia
| | | | - Jeanette E Stok
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD, Australia
| | - Glen M Boyle
- QIMR Berghofer Medical Research Institute, PO Royal Brisbane Hospital, Brisbane, 4029, QLD, Australia
| | - Carly J Pierce
- QIMR Berghofer Medical Research Institute, PO Royal Brisbane Hospital, Brisbane, 4029, QLD, Australia
| | - Stuart W Littler
- CISRO Manufacturing, Ian Wark Laboratory, Melbourne, 3168, Victoria (VIC, Australia
| | - David A Winkler
- CISRO Manufacturing, Ian Wark Laboratory, Melbourne, 3168, Victoria (VIC, Australia.,Monash Institute of Pharmaceutical Sciences, Parkville, 3052, MU, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD, Australia
| | - Cielo Pasay
- QIMR Berghofer Medical Research Institute, PO Royal Brisbane Hospital, Brisbane, 4029, QLD, Australia
| | - James J De Voss
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD, Australia
| | - James McCarthy
- QIMR Berghofer Medical Research Institute, PO Royal Brisbane Hospital, Brisbane, 4029, QLD, Australia.,Australian Centre for International and Tropical Health, UQ, Australia
| | - Peter G Parsons
- QIMR Berghofer Medical Research Institute, PO Royal Brisbane Hospital, Brisbane, 4029, QLD, Australia
| | | | - Maree T Smith
- Centre for Integrated Preclinical Drug Development, UQ, Australia
| | | | - Susan K Nilsson
- CISRO Manufacturing, Ian Wark Laboratory, Melbourne, 3168, Victoria (VIC, Australia.,Australian Regenerative Medicine Institute, Monash University (MU), Melbourne, 3168, VIC, Australia
| | - John Tsanaktsidis
- CISRO Manufacturing, Ian Wark Laboratory, Melbourne, 3168, Victoria (VIC, Australia.
| | - G Paul Savage
- CISRO Manufacturing, Ian Wark Laboratory, Melbourne, 3168, Victoria (VIC, Australia.
| | - Craig M Williams
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD, Australia.
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18
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Chalmers BA, Xing H, Houston S, Clark C, Ghassabian S, Kuo A, Cao B, Reitsma A, Murray CP, Stok JE, Boyle GM, Pierce CJ, Littler SW, Winkler DA, Bernhardt PV, Pasay C, De Voss JJ, McCarthy J, Parsons PG, Walter GH, Smith MT, Cooper HM, Nilsson SK, Tsanaktsidis J, Savage GP, Williams CM. Validating Eaton's Hypothesis: Cubane as a Benzene Bioisostere. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201510675] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Benjamin A. Chalmers
- School of Chemistry and Molecular Biosciences University of Queensland (UQ) Brisbane 4072 Queensland (QLD Australia
| | - Hui Xing
- School of Chemistry and Molecular Biosciences University of Queensland (UQ) Brisbane 4072 Queensland (QLD Australia
| | - Sevan Houston
- School of Chemistry and Molecular Biosciences University of Queensland (UQ) Brisbane 4072 Queensland (QLD Australia
| | | | | | - Andy Kuo
- Centre for Integrated Preclinical Drug Development, UQ Australia
| | - Benjamin Cao
- CISRO Manufacturing Ian Wark Laboratory Melbourne 3168 Victoria (VIC Australia
- Australian Regenerative Medicine Institute Monash University (MU) Melbourne 3168 VIC Australia
| | - Andrea Reitsma
- CISRO Manufacturing Ian Wark Laboratory Melbourne 3168 Victoria (VIC Australia
- Australian Regenerative Medicine Institute Monash University (MU) Melbourne 3168 VIC Australia
| | | | - Jeanette E. Stok
- School of Chemistry and Molecular Biosciences University of Queensland (UQ) Brisbane 4072 Queensland (QLD Australia
| | - Glen M. Boyle
- QIMR Berghofer Medical Research Institute PO Royal Brisbane Hospital Brisbane 4029 QLD Australia
| | - Carly J. Pierce
- QIMR Berghofer Medical Research Institute PO Royal Brisbane Hospital Brisbane 4029 QLD Australia
| | - Stuart W. Littler
- CISRO Manufacturing Ian Wark Laboratory Melbourne 3168 Victoria (VIC Australia
| | - David A. Winkler
- CISRO Manufacturing Ian Wark Laboratory Melbourne 3168 Victoria (VIC Australia
- Monash Institute of Pharmaceutical Sciences Parkville 3052 MU Australia
| | - Paul V. Bernhardt
- School of Chemistry and Molecular Biosciences University of Queensland (UQ) Brisbane 4072 Queensland (QLD Australia
| | - Cielo Pasay
- QIMR Berghofer Medical Research Institute PO Royal Brisbane Hospital Brisbane 4029 QLD Australia
| | - James J. De Voss
- School of Chemistry and Molecular Biosciences University of Queensland (UQ) Brisbane 4072 Queensland (QLD Australia
| | - James McCarthy
- QIMR Berghofer Medical Research Institute PO Royal Brisbane Hospital Brisbane 4029 QLD Australia
- Australian Centre for International and Tropical Health, UQ Australia
| | - Peter G. Parsons
- QIMR Berghofer Medical Research Institute PO Royal Brisbane Hospital Brisbane 4029 QLD Australia
| | | | - Maree T. Smith
- Centre for Integrated Preclinical Drug Development, UQ Australia
| | | | - Susan K. Nilsson
- CISRO Manufacturing Ian Wark Laboratory Melbourne 3168 Victoria (VIC Australia
- Australian Regenerative Medicine Institute Monash University (MU) Melbourne 3168 VIC Australia
| | - John Tsanaktsidis
- CISRO Manufacturing Ian Wark Laboratory Melbourne 3168 Victoria (VIC Australia
| | - G. Paul Savage
- CISRO Manufacturing Ian Wark Laboratory Melbourne 3168 Victoria (VIC Australia
| | - Craig M. Williams
- School of Chemistry and Molecular Biosciences University of Queensland (UQ) Brisbane 4072 Queensland (QLD Australia
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Abstract
Cytochrome P450cin (P450cin) (CYP176A1) is a bacterial P450 enzyme that catalyses the enantiospecific hydroxylation of 1,8-cineole to (1R)-6β-hydroxycineole when reconstituted with its natural reduction-oxidation (redox) partner cindoxin, E. coli flavodoxin reductase, and NADPH as a source of electrons. This catalytic system has become a useful tool in the study of P450s as not only can large quantities of P450cin be prepared and rates of oxidation up to 1,500 min(-1) achieved, but it also displays a number of unusual characteristics. These include an asparagine residue in P450cin that has been found in place of the usual conserved threonine residue observed in most P450s. In general, this conserved threonine controls oxygen activation to create the potent ferryl (Fe(IV=O) porphyrin cation radical required for substrate oxidation. Another atypical characteristic of P450cin is that it utilises an FMN-containing redoxin (cindoxin) rather than a ferridoxin as is usually observed with other bacterial P450s (e.g. P450cam). This chapter will review what is currently known about P450cin and how this enzyme has provided a greater understanding of P450s in general.
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Affiliation(s)
- Jeanette E Stok
- School of Chemistry and Molecular Biosciences, University of Queensland, St. Lucia, Brisbane, 4072, Australia
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Stok JE, Yamada S, Farlow AJ, Slessor KE, De Voss JJ. Cytochrome P450(cin) (CYP176A1) D241N: investigating the role of the conserved acid in the active site of cytochrome P450s. Biochim Biophys Acta 2013; 1834:688-96. [PMID: 23305928 DOI: 10.1016/j.bbapap.2012.12.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 12/14/2012] [Accepted: 12/28/2012] [Indexed: 10/27/2022]
Abstract
P450(cin) (CYP176A) is a rare bacterial P450 in that contains an asparagine (Asn242) instead of the conserved threonine that almost all other P450s possess that directs oxygen activation by the heme prosthetic group. However, P450(cin) does have the neighbouring, conserved acid (Asp241) that is thought to be involved indirectly in the protonation of the dioxygen and affect the lifetime of the ferric-peroxo species produced during oxygen activation. In this study, the P450(cin) D241N mutant has been produced and found to be analogous to the P450(cam) D251N mutant. P450(cin) catalyses the hydroxylation of cineole to give only (1R)-6β-hydroxycineole and is well coupled (NADPH consumed: product produced). The P450(cin) D241N mutant also hydroxylated cineole to produce only (1R)-6β-hydroxycineole, was moderately well coupled (31±3%) but a significant reduction in the rate of the reaction (2% as compared to wild type) was observed. Catalytic oxidation of a variety of substrates by D241N P450(cin) were used to examine if typical reactions ascribed to the ferric-peroxo species increased as this intermediate is known to be more persistent in the P450(cam) D251N mutant. However, little change was observed in the product profiles of each of these substrates between wild type and mutant enzymes and no products consistent with chemistry of the ferric-peroxo species were observed to increase.
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Affiliation(s)
- Jeanette E Stok
- Department of Chemistry, School of Chemistry and Molecular Biosciences, University of Queensland, St. Lucia, Brisbane QLD 4072, Australia.
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Slessor KE, Hawkes DB, Farlow A, Pearson AG, Stok JE, De Voss JJ. An in vivo cytochrome P450cin (CYP176A1) catalytic system for metabolite production. ACTA ACUST UNITED AC 2012. [DOI: 10.1016/j.molcatb.2012.03.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Johnston WA, Hunter DJB, Noble CJ, Hanson GR, Stok JE, Hayes MA, De Voss JJ, Gillam EMJ. Cytochrome P450 is present in both ferrous and ferric forms in the resting state within intact Escherichia coli and hepatocytes. J Biol Chem 2011; 286:40750-9. [PMID: 21976668 DOI: 10.1074/jbc.m111.300871] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cytochrome P450 enzymes (P450s) are exceptionally versatile monooxygenases, mediating hydroxylations of unactivated C-H bonds, epoxidations, dealkylations, and N- and S-oxidations as well as other less common reactions. In the conventional view of the catalytic cycle, based upon studies of P450s in vitro, substrate binding to the Fe(III) resting state facilitates the first 1-electron reduction of the heme. However, the resting state of P450s in vivo has not been examined. In the present study, whole cell difference spectroscopy of bacterial (CYP101A1 and CYP176A1, i.e. P450cam and P450cin) and mammalian (CYP1A2, CYP2C9, CYP2A6, CYP2C19, and CYP3A4) P450s expressed within intact Escherichia coli revealed that both Fe(III) and Fe(II) forms of the enzyme are present in the absence of substrates. The relevance of this finding was supported by similar observations of Fe(II) P450 heme in intact rat hepatocytes. Electron paramagnetic resonance (EPR) spectroscopy of the bacterial forms in intact cells showed that a proportion of the P450 in cells was in an EPR-silent form in the native state consistent with the presence of Fe(II) P450. Coexpression of suitable cognate electron donors increased the degree of endogenous reduction to over 80%. A significant proportion of intracellular P450 remained in the Fe(II) form after vigorous aeration of cells. The addition of substrates increased the proportion of Fe(II) heme, suggesting a kinetic gate to heme reduction in the absence of substrate. In summary, these observations suggest that the resting state of P450s should be regarded as a mixture of Fe(III) and Fe(II) forms in both aerobic and oxygen-limited conditions.
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Affiliation(s)
- Wayne A Johnston
- School of Biomedical Sciences, The University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
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Ge W, Clifton IJ, Stok JE, Adlington RM, Baldwin JE, Rutledge PJ. Crystallographic studies on the binding of selectively deuterated LLD- and LLL-substrate epimers by isopenicillin N synthase. Biochem Biophys Res Commun 2010; 398:659-64. [DOI: 10.1016/j.bbrc.2010.06.129] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2010] [Accepted: 06/30/2010] [Indexed: 10/19/2022]
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Ge W, Clifton IJ, Stok JE, Adlington RM, Baldwin JE, Rutledge PJ. The crystal structure of anlll-configured depsipeptide substrate analogue bound to isopenicillin N synthase. Org Biomol Chem 2010; 8:122-7. [DOI: 10.1039/b910170e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Slessor KE, Stok JE, Cavaignac SM, Hawkes DB, Ghasemi Y, De Voss JJ. Cineole biodegradation: molecular cloning, expression and characterisation of (1R)-6beta-hydroxycineole dehydrogenase from Citrobacter braakii. Bioorg Chem 2009; 38:81-6. [PMID: 20089292 DOI: 10.1016/j.bioorg.2009.12.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Revised: 12/04/2009] [Accepted: 12/04/2009] [Indexed: 11/16/2022]
Abstract
The first steps in the biodegradation of 1,8-cineole involve the introduction of an alcohol and its subsequent oxidation to a ketone. In Citrobacter braakii, cytochrome P450(cin) has previously been demonstrated to perform the first oxidation to produce (1R)-6beta-hydroxycineole. In this study, we have cloned cinD from C. braakii and expressed the gene product, which displays significant homology to a number of short-chain alcohol dehydrogenases. It was demonstrated that the gene product of cinD exhibits (1R)-6beta-hydroxycineole dehydrogenase activity, the second step in the degradation of 1,8-cineole. All four isomers of 6-hydroxycineole were examined but only (1R)-6beta-hydroxycineole was converted to (1R)-6-ketocineole. The (1R)-6beta-hydroxycineole dehydrogenase exhibited a strict requirement for NAD(H), with no reaction observed in the presence of NADP(H). The enzyme also catalyses the reverse reaction, reducing (1R)-6-ketocineole to (1R)-6beta-hydroxycineole. During this study the N-terminal His-tag used to assist protein purification was found to interfere with NAD(H) binding and lower enzyme activity. This could be recovered by the addition of Ni(2+) ions or proteolytic removal of the His-tag.
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Affiliation(s)
- Kate E Slessor
- School of Chemistry and Molecular Biosciences, University of Queensland, St. Lucia, Brisbane QLD 4072, Australia
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26
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Ge W, Clifton IJ, Howard-Jones AR, Stok JE, Adlington RM, Baldwin JE, Rutledge PJ. Structural Studies on the Reaction of Isopenicillin N Synthase with a Sterically Demanding Depsipeptide Substrate Analogue. Chembiochem 2009; 10:2025-31. [DOI: 10.1002/cbic.200900080] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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27
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Ge W, Clifton IJ, Stok JE, Adlington RM, Baldwin JE, Rutledge PJ. Isopenicillin N Synthase Mediates Thiolate Oxidation to Sulfenate in a Depsipeptide Substrate Analogue: Implications for Oxygen Binding and a Link to Nitrile Hydratase? J Am Chem Soc 2008; 130:10096-102. [DOI: 10.1021/ja8005397] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Stok JE, Baldwin JE. Development of enzyme-linked immunosorbent assays for the detection of deacetoxycephalosporin C and isopenicillin N synthase activity. Anal Chim Acta 2006; 577:153-62. [PMID: 17723666 DOI: 10.1016/j.aca.2006.06.040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2006] [Revised: 06/13/2006] [Accepted: 06/16/2006] [Indexed: 10/24/2022]
Abstract
Although there are a number of existing assays for monitoring the activity of both isopenicillin N synthase (IPNS) and deacetoxycephalosporin C synthase (DAOCS), none have demonstrated the qualities required for screening a mutant library. Hence, enzyme-linked immunosorbent assays (ELISAs) for IPNS and DAOCS were developed based on the detection of the catalytic turnover products isopenicillin N and cephalexin/phenylacetyl-7-aminodeacetoxycephalosporanic acid (G-7-ADCA), respectively. These assays are relatively fast compared to existing assays, such as the hole-plate bioassay, and are amenable with high-throughput screening. Both the IPNS and DAOCS-ELISAs were optimised for use with crude protein extracts rather than purified protein, thereby eliminating any additional time required for purification. The ELISA developed for the detection of cephalexin had an IC50 value of 154+/-9 ng mL(-1) and LOD of 7.2+/-2.2 ng mL(-1) under conditions required for the assay. Good recoveries and correlation was observed for spiked samples when the concentration of crude protein was kept below 1 mg mL(-1). The DAOCS-ELISA was found to have increased sensitivity compared to the hole-plate bioassay (10.3 microg mL(-1)). The IPNS-ELISA did not significantly increase the sensitivity (approximately 5 microg mL(-1)) compared to that of the hole-plate bioassay (16 microg mL(-1)) for isopenicillin N. The minimum amount of crude protein extract required for producing detectable amounts of product for both assays was below 0.5% of the maximum amount of protein that the assay could contain without any effect on the ELISA. This suggests that when screening a mutant library, mutants producing low amounts of the product could still be detected using these assays.
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Affiliation(s)
- Jeanette E Stok
- Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom.
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Huang H, Stok JE, Stoutamire DW, Gee SJ, Hammock BD. Development of optically pure pyrethroid-like fluorescent substrates for carboxylesterases. Chem Res Toxicol 2005; 18:516-27. [PMID: 15777092 DOI: 10.1021/tx049773h] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pyrethroids are now the world's most extensively used insecticides. One of the common metabolic routes of pyrethroid insecticides in living systems is hydrolysis by carboxylesterases, and this hydrolysis may be stereospecific since most pyrethroid insecticides have chiral centers. In previous studies, pyrethroid-like fluorescent substrates have been shown to be hydrolyzed in a fashion similar to actual pyrethroids. It is important to synthesize the stereoisomers of pyrethroid-like fluorescent substrates to study the stereointeraction between carboxylesterases and these substrates. In this study, an effective synthetic method for preparing optically enriched (R)- and (S)-alpha-2-hydroxy-2-(6-methoxy-2-naphthyl)acetonitrile was developed. With this alcohol, an efficient synthetic route for preparation of optically pure cypermethrin and fenvalerate analogues was provided. Identification of these stereoisomers was determined based on GC, HPLC, 1H NMR, and X-ray crystallography. In addition, stereointeraction between carboxylesterases and chiral fluorescent substrates indicated that (i) stereospecificity of recombinant mouse liver carboxylesterases (NCBI accession nos. BAC36707 and NM_133960) varied significantly (up to 300-fold difference) with different stereoisomers of cypermethrin and fenvalerate analogues; (ii) on the basis of Vmax, the sensitivity of this analytical method, using a single stereoisomer of cypermethrin analogues instead of a mixture of eight stereosiomers, could be enhanced by 4-6 times for detection of these carboxylesterases; and (iii) possible usage of these carboxylesterases for chiral synthesis is discussed.
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Affiliation(s)
- Huazhang Huang
- Department of Entomology and Cancer Research Center, University of California, Davis, California 95616, USA
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Abstract
Estrogen biosynthesis and proteolysis are both important processes involved in ovarian follicular development, which may be influenced by cytochrome P450 (CYP)-dependent fatty acid metabolites. However, CYP-dependent lipid metabolism has not been characterized with respect to follicular maturation in vivo. Therefore, follicular fluid was collected in the hours before and after the LH surge in pigs, and concentrations of epoxy, hydroxy, and dihydroxy lipids were measured by liquid chromatography tandem mass spectrometry. Arachidonate oxidation and epoxyeicosatrienoic acid hydrolysis to dihydroxyeicosatrienoic acids (DHETs) were also assessed in thecal and granulosa tissue fractions, and the expression of CYP epoxygenases was evaluated by immunoblots using available antisera. To evaluate soluble epoxide hydrolase (sEH) expression, the porcine sEH was cloned from ovarian tissue, expressed and purified for antibody generation. The follicular fluid oxylipin concentrations ranged from 1-150 nm depending on the compound and estrous stage. The follicular fluid concentrations of CYP-dependent oxylipins increased at estrus, as did sEH expression; however, significant changes in epoxides were not observed, and the 11,12-DHET peak was delayed. The ratio of 14,15-DHET:11,12-DHET across all samples correlated with the log of follicular fluid estradiol concentrations (P < 0.01). Epoxygenase activities were similar in theca and granulosa, varying little with follicular development, whereas the decline of a single CYP2J isoform at ovulation was observed by immunoblots. The sEH activity was higher in granulosa than in theca. Finally, the dynamic changes in follicular CYP-dependent arachidonic acid metabolites and their modulatory function in vascular models suggest roles for these metabolites in follicular maturation, which may include regulation of estradiol biosynthesis and preovulatory remodeling of the follicular wall that should be fully explored in future studies.
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Affiliation(s)
- J W Newman
- Veterinary Medicine-Population Health & Reproduction, School of Veterinary Medicine, 1131 Tupper Hall, University of California, Davis California 95616, USA
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Stok JE, Goloshchapov A, Song C, Wheelock CE, Derbel MBH, Morisseau C, Hammock BD. Investigation of the role of a second conserved serine in carboxylesterases via site-directed mutagenesis. Arch Biochem Biophys 2004; 430:247-55. [PMID: 15369824 DOI: 10.1016/j.abb.2004.06.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2004] [Revised: 06/16/2004] [Indexed: 11/20/2022]
Abstract
Carboxylesterases are enzymes that catalyze the hydrolysis of ester and amide moieties. These enzymes have an active site that is composed of a nucleophile (Ser), a base (His), and an acid (Glu) that is commonly known as a catalytic triad. It has previously been observed that the majority of carboxylesterases and lipases contain a second conserved serine in their active site [Proteins, 34 (1999) 184]. To investigate whether this second serine is also involved in the catalytic mechanism, it was mutated to an alanine, a glycine or a cysteine. Site-directed mutagenesis of this conserved serine resulted in a loss of specific activity, in both the S247G and S247A mutants (5- to 15-fold), which was due to a decrease in the rate of catalysis (kcat). Due to the instability of the S247C mutant no reliable data could be attained. A carbamate inhibitor, carbaryl, was then employed to investigate whether this decrease in the kcat was due to the rate of formation of the acyl-enzyme intermediate (k2) or the rate of deacylation (k3). The S247A mutant was found only to alter k2 (2.5-fold decrease), with no effect on k3. Together with information inferred from a human carboxylesterase crystal structure, it was concluded that this serine provides an important structural support for the spatial orientation of the glutamic acid, stabilizing the catalytic triad so that it can perform the hydrolysis.
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Affiliation(s)
- Jeanette E Stok
- Department of Entomology, University of California, Davis 95616, USA
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Stok JE, Huang H, Jones PD, Wheelock CE, Morisseau C, Hammock BD. Identification, expression, and purification of a pyrethroid-hydrolyzing carboxylesterase from mouse liver microsomes. J Biol Chem 2004; 279:29863-9. [PMID: 15123619 DOI: 10.1074/jbc.m403673200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Carboxylesterases are enzymes that catalyze the hydrolysis of a wide range of ester-containing endogenous and xenobiotic compounds. Although the use of pyrethroids is increasing, the specific enzymes involved in the hydrolysis of these insecticides have yet to be identified. A pyrethroid-hydrolyzing enzyme was partially purified from mouse liver microsomes using a fluorescent reporter similar in structure to cypermethrin (Shan, G., and Hammock, B. D. (2001) Anal. Biochem. 299, 54-62 and Wheelock, C. E., Wheelock, A. M., Zhang, R., Stok, J. E., Morisseau, C., Le Valley, S. E., Green, C. E., and Hammock, B. D. (2003) Anal. Biochem. 315, 208-222) and subsequently identified as a carboxylesterase (NCBI accession number BAC36707). The expressed sequence tag was then cloned, expressed in baculovirus, and purified to homogeneity. Kinetic constants for a large number of both type I and type II pyrethroid or pyrethroid-like substrates were determined. This esterase possesses similar kinetic constants for cypermethrin and its fluorescent-surrogate (k(cat) = 0.12 +/- 0.03 versus 0.11 +/- 0.01 s(-1)). Compared with their cis- counterparts, trans-permethrin and cypermethrin were hydrolyzed 22- and 4-fold faster, respectively. Of the four fenvalerate isomers the (2R)(alphaR)-isomer was hydrolyzed at least 1 order of magnitude faster than any other isomer. However, it is unlikely that this enzyme accounts for the total pyrethroid hydrolysis in the microsomes because both isoelectrofocusing and native PAGE indicate the presence of a second region of cypermethrin-metabolizing enzymes. A second carboxylesterase gene (NCBI accession number NM_133960), isolated during a cDNA mouse liver library screening, was also found to hydrolyze pyrethroids. Both these enzymes could be used as preliminary tools in establishing the relative toxicity of new pyrethroids.
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Affiliation(s)
- Jeanette E Stok
- Department of Entomology and University of California Davis Cancer Research Center, University of California, Davis, California 95616, USA
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Kamita SG, Hinton AC, Wheelock CE, Wogulis MD, Wilson DK, Wolf NM, Stok JE, Hock B, Hammock BD. Juvenile hormone (JH) esterase: why are you so JH specific? Insect Biochem Mol Biol 2003; 33:1261-1273. [PMID: 14599498 DOI: 10.1016/j.ibmb.2003.08.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Juvenile hormone esterases (JHEs) from six insects belonging to three orders (Lepidoptera, Coleoptera, and Diptera) were compared in terms of their deduced amino acid sequence and biochemical properties. The four lepidopteran JHEs showed from 52% to 59% identity to each other and about 30% identity to the coleopteran and dipteran JHEs. The JHE of Manduca sexta was remarkably resistant to the addition of organic co-solvents and detergent; in some cases, it demonstrated significant activation of activity. Trifluoromethylketone (TFK) inhibitors with chain lengths of 8, 10 or 12 carbons were highly effective against both lepidopteran and coleopteran JHEs. The coleopteran JHE remained sensitive to TFK inhibitors with a chain length of 6 carbons, whereas the lepidopteran JHEs were significantly less sensitive. When the chain was altered to a phenethyl moiety, the coleopteran JHE remained moderately sensitive, while the lepidopteran JHEs were much less sensitive. The lepidopteran and coleopteran JHEs did not show dramatic differences in specificity to alpha-naphthyl and rho-nitrophenyl substrates. However, as the chain length of the alpha-naphthyl substrates increased from propionate to caprylate, there was a trend towards reduced activity. The JHE of M. sexta was crystallized and the properties of the crystal suggest a high-resolution structure will follow.
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Affiliation(s)
- Shizuo G Kamita
- Department of Entomology and Cancer Research Center, University of California, 303 Briggs Hall, 1 Shields Avenue, Davis, CA 95616, USA
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Wheelock CE, Wheelock AM, Zhang R, Stok JE, Morisseau C, Le Valley SE, Green CE, Hammock BD. Evaluation of alpha-cyanoesters as fluorescent substrates for examining interindividual variation in general and pyrethroid-selective esterases in human liver microsomes. Anal Biochem 2003; 315:208-22. [PMID: 12689831 DOI: 10.1016/s0003-2697(03)00002-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Carboxylesterases hydrolyze many pharmaceuticals and agrochemicals and have broad substrate selectivity, requiring a suite of substrates to measure hydrolytic profiles. To develop new esterase substrates, a series of alpha-cyanoesters that yield fluorescent products upon hydrolysis was evaluated for use in carboxylesterase assays. The use of these substrates as surrogates for Type II pyrethroid hydrolysis was tested. The results suggest that these novel analogs are appropriate for the development of high-throughput assays for pyrethroid hydrolase activity. A set of human liver microsomes was then used to determine the ability of these substrates to report esterase activity across a small population. Results were compared against standard esterase substrates. A number of the esterase substrates showed correlations, demonstrating the broad substrate selectivity of these enzymes. However, for several of the substrates, no correlations in hydrolysis rates were observed, suggesting that multiple carboxylesterase isozymes are responsible for the array of substrate hydrolytic activity. These new substrates were then compared against alpha-naphthyl acetate and 4-methylumbelliferyl acetate for their ability to detect hydrolytic activity in both one- and two-dimensional native electrophoresis gels. Cyano-2-naphthylmethyl butanoate was found to visualize more activity than either commercial substrate. These applications demonstrate the utility of these new substrates as both general and pyrethroid-selective reporters of esterase activity.
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Affiliation(s)
- Craig E Wheelock
- Department of Entomology and Cancer Research Center, University of California, Davis, CA 95616, USA
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Abstract
The cytochromes P450 are a large family of oxidative haemoproteins that are responsible for a wide variety of oxidative transformations in a variety of organisms. This review focuses upon the reactions catalyzed specifically by bacterial enzymes, which includes aliphatic hydroxylation, alkene epoxidation, aromatic hydroxylation, oxidative phenolic coupling, heteroatom oxidation and dealkylation, and multiple oxidations including C–C bond cleavage. The potential for the practical application of the oxidizing power of these enzymes is briefly discussed.
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Fletcher MT, Wood BJ, Brereton IM, Stok JE, De Voss JJ, Kitching W. [(18)O]-oxygen incorporation reveals novel pathways in spiroacetal biosynthesis by Bactrocera cacuminata and B. cucumis. J Am Chem Soc 2002; 124:7666-7. [PMID: 12083914 DOI: 10.1021/ja026215l] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The origins of the oxygen atoms in 1,7-dioxaspiro[5.5]undecane (1) and hydroxyspiroacetal (2) from Bactrocera cacuminata, and in 2,8-dimethyl-1,7-dioxaspiro[5.5]undecane (3) and hydroxyspiroacetal (4) from B. cucumis, have been investigated by incorporation studies from both [(18)O(2)]-dioxygen and [(18)O]-water. Combined GC-MS examination and high-field NMR analysis have demonstrated that all oxygen atoms in 1 and 2 from B. cacuminata are dioxygen derived, but in contrast, the spiroacetals 3 and 4 from B. cucumis incorporate one ring oxygen from water and one ring oxygen (and the hydroxyl oxygen in 4) from [(18)O(2)]-dioxygen. These results reveal not only the generality of monoxygenase mediation of spiroacetal formation in Bactrocera sp., but also an unexpected complexity in their biosynthesis. A general paradigm accommodating these and other observations is presented.
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Affiliation(s)
- Mary T Fletcher
- Department of Chemistry and Centre for Magnetic Resonance, The University of Queensland, Brisbane 4072, Australia
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Stok JE, Lang CS, Schwartz BD, Fletcher MT, Kitching W, De Voss JJ. Carbon hydroxylation of alkyltetrahydropyranols: a paradigm for spiroacetal biosynthesis in Bactrocera sp. Org Lett 2001; 3:397-400. [PMID: 11428023 DOI: 10.1021/ol0069047] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[figure: see text] In a number of Bactrocera species the penultimate step in the biosynthesis of spiroacetals is shown to be the hydroxylation of an alkyltetrahydropyranol followed by cyclization. The monooxygenases that catalyze this side chain hydroxylation show a strong preference for oxidation four carbons from the hemiketal center, to produce the spiroacetal. The hydroxy spiroacetals observed in Bactrocera appear to derive from direct oxidation of the parent spiroacetals and not from alternate precursors.
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Affiliation(s)
- J E Stok
- Department of Chemistry, University of Queensland, Brisbane, 4072 Australia
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Stok JE, De Voss J. Expression, Purification, and Characterization of BioI: A Carbon–Carbon Bond Cleaving Cytochrome P450 Involved in Biotin Biosynthesis in Bacillus subtilis. Arch Biochem Biophys 2000; 384:351-60. [PMID: 11368323 DOI: 10.1006/abbi.2000.2067] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Pimelic acid formation for biotin biosynthesis in Bacillus subtilis has been proposed to involve a cytochrome P450 encoded by the gene bioI. We have subcloned biol and overexpressed the encoded protein, Biol. A purification protocol was developed utilizing ion exchange, gel filtration, and hydroxyapatite chromatography. Investigation of the purified BioI by UV-visible spectroscopy revealed spectral properties characteristic of a cytochrome P450 enzyme. BioI copurifies with acylated Escherichia coli acyl carrier protein (ACP), suggesting that in vivo a fatty acid substrate may be presented to BioI as an acyl-ACP. A combination of electrospray mass spectrometry of the intact acyl-ACP and GCMS indicated a range of fatty acids were bound to the ACP. A catalytically active system has been established employing E. coli flavodoxin reductase and a novel, heterologous flavodoxin as the redox partners for BioI. In this system, BioI cleaves a carbon-carbon bond of an acyl-ACP to generate a pimeloyl-ACP equivalent, from which pimelic acid is isolated after base-catalyzed saponification. A range of free fatty acids have also been explored as potential alternative substrates for BioI, with C16 binding most tightly to the enzyme. These fatty acids are also metabolized to dicarboxylic acids, but with less regiospecificity than is observed with acyl-ACPs. A possible mechanism for this transformation is discussed. These results strongly support the proposed role for BioI in biotin biosynthesis. In addition, the production of pimeloyl-ACP explains the ability of BioI to function as a pimeloyl CoA source in E. coli, which, unlike B. subtilis, is unable to utilize free pimelic acid for biotin production.
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Affiliation(s)
- J E Stok
- Department of Chemistry, University of Queensland, Brisbane, Australia
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