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Amaya JA, Manley OM, Bian JC, Rutland CD, Leschinsky N, Ratigan SC, Makris TM. Enhancing ferryl accumulation in H 2O 2-dependent cytochrome P450s. J Inorg Biochem 2024; 252:112458. [PMID: 38141432 DOI: 10.1016/j.jinorgbio.2023.112458] [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: 11/02/2023] [Revised: 12/08/2023] [Accepted: 12/16/2023] [Indexed: 12/25/2023]
Abstract
A facile strategy is presented to enhance the accumulation of ferryl (iron(IV)-oxo) species in H2O2 dependent cytochrome P450s (CYPs) of the CYP152 family. We report the characterization of a highly chemoselective CYP decarboxylase from Staphylococcus aureus (OleTSA) that is soluble at high concentrations. Examination of OleTSA Compound I (CpdI) accumulation with a variety of fatty acid substrates reveals a dependence on resting spin-state equilibrium. Alteration of this equilibrium through targeted mutagenesis of the proximal pocket favors the high-spin form, and as a result, enhances Cpd-I accumulation to nearly stoichiometric yields.
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Affiliation(s)
- Jose A Amaya
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, United States of America
| | - Olivia M Manley
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, United States of America; Department of Structural and Molecular Biochemistry, North Carolina State University, Raleigh, NC 27695, United States of America
| | - Julia C Bian
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, United States of America
| | - Cooper D Rutland
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, United States of America
| | - Nicholas Leschinsky
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, United States of America
| | - Steven C Ratigan
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, United States of America
| | - Thomas M Makris
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, United States of America; Department of Structural and Molecular Biochemistry, North Carolina State University, Raleigh, NC 27695, United States of America; Department of Chemistry, North Carolina State University, Raleigh, NC 27695, United States of America.
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2
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Yan Y, Wu J, Hu G, Gao C, Guo L, Chen X, Liu L, Song W. Current state and future perspectives of cytochrome P450 enzymes for C–H and C=C oxygenation. Synth Syst Biotechnol 2022; 7:887-899. [PMID: 35601824 PMCID: PMC9112060 DOI: 10.1016/j.synbio.2022.04.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 04/24/2022] [Accepted: 04/26/2022] [Indexed: 01/11/2023] Open
Abstract
Cytochrome P450 enzymes (CYPs) catalyze a series of C–H and C=C oxygenation reactions, including hydroxylation, epoxidation, and ketonization. They are attractive biocatalysts because of their ability to selectively introduce oxygen into inert molecules under mild conditions. This review provides a comprehensive overview of the C–H and C=C oxygenation reactions catalyzed by CYPs and the various strategies for achieving higher selectivity and enzymatic activity. Furthermore, we discuss the application of C–H and C=C oxygenation catalyzed by CYPs to obtain the desired chemicals or pharmaceutical intermediates in practical production. The rapid development of protein engineering for CYPs provides excellent biocatalysts for selective C–H and C=C oxygenation reactions, thereby promoting the development of environmentally friendly and sustainable production processes.
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Affiliation(s)
- Yu Yan
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi, 214122, China
| | - Jing Wu
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi, 214122, China
| | - Guipeng Hu
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi, 214122, China
| | - Cong Gao
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China
| | - Liang Guo
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China
| | - Xiulai Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China
| | - Liming Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China
| | - Wei Song
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi, 214122, China
- Corresponding author.
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3
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Dixit VA, Warwicker J, Visser SP. How Do Metal Ions Modulate the Rate‐Determining Electron‐Transfer Step in Cytochrome P450 Reactions? Chemistry 2020; 26:15270-15281. [DOI: 10.1002/chem.202003024] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Indexed: 12/16/2022]
Affiliation(s)
- Vaibhav A. Dixit
- Department of Pharmacy Birla Institute of Technology and Sciences Pilani (BITS-Pilani) Vidya Vihar Campus 41 Pilani 333031 Rajasthan India
| | - Jim Warwicker
- Manchester Institute of Biotechnology The University of Manchester 131 Princess Street Manchester M17DN United Kingdom
- Department of Chemistry The University of Manchester Oxford Road Manchester M139PL United Kingdom
| | - Sam P. Visser
- Manchester Institute of Biotechnology The University of Manchester 131 Princess Street Manchester M17DN United Kingdom
- Department of Chemical Engineering and Analytical Science The University of Manchester Oxford Road Manchester M13 9PL United Kingdom
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4
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Visser SP. Second‐Coordination Sphere Effects on Selectivity and Specificity of Heme and Nonheme Iron Enzymes. Chemistry 2020; 26:5308-5327. [DOI: 10.1002/chem.201905119] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 12/04/2019] [Indexed: 12/11/2022]
Affiliation(s)
- Sam P. Visser
- The Manchester Institute of Biotechnology and Department of Chemical Engineering and Analytical ScienceThe University of Manchester 131 Princess Street Manchester M1 7DN UK
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5
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Chuo SW, Wang LP, Britt RD, Goodin DB. An Intermediate Conformational State of Cytochrome P450cam-CN in Complex with Putidaredoxin. Biochemistry 2019; 58:2353-2361. [PMID: 30994334 DOI: 10.1021/acs.biochem.9b00192] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Cytochrome P450cam is an archetypal example of the vast family of heme monooxygenases and serves as a model for an enzyme that is highly specific for both its substrate and reductase. During catalysis, it undergoes significant conformational changes of the F and G helices upon binding its substrate and redox partner, putidaredoxin (Pdx). Recent studies have shown that Pdx binding to the closed camphor-bound form of ferric P450cam results in its conversion to a fully open state. However, during catalytic turnover, it remains unclear whether this same conformational change also occurs or whether it is coupled to the formation of the critical compound I intermediate. Here, we have examined P450cam bound simultaneously by camphor, CN-, and Pdx as a mimic of the catalytically competent ferrous oxy-P450cam-Pdx state. The combined use of double electron-electron resonance and molecular dynamics showed direct observation of intermediate conformational states of the enzyme upon CN- and subsequent Pdx binding. This state is coupled to the movement of the I helix and residues at the active site, including Arg-186, Asp-251, and Thr-252. These movements enable occupation of a water molecule that has been implicated in proton delivery and peroxy bond cleavage to give compound I. These findings provide a detailed understanding of how the Pdx-induced conformational change may sequentially promote compound I formation followed by product release, while retaining stereoselective hydroxylation of the substrate of this highly specific monooxygenase.
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Affiliation(s)
- Shih-Wei Chuo
- Department of Chemistry , University of California, Davis , One Shields Avenue , Davis , California 95616 , United States
| | - Lee-Ping Wang
- Department of Chemistry , University of California, Davis , One Shields Avenue , Davis , California 95616 , United States
| | - R David Britt
- Department of Chemistry , University of California, Davis , One Shields Avenue , Davis , California 95616 , United States
| | - David B Goodin
- Department of Chemistry , University of California, Davis , One Shields Avenue , Davis , California 95616 , United States
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6
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Goodin DB, Chuo SW, Liou SH. Conformational Changes in Cytochrome P450cam and the Effector Role of Putidaredoxin. DIOXYGEN-DEPENDENT HEME ENZYMES 2018. [DOI: 10.1039/9781788012911-00292] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The cytochromes P450 form an enormous family of over 20 000 enzyme variants found in all branches of life. They catalyze the O2 dependent monooxygenation of a wide range of substrates in reactions important to drug metabolism, biosynthesis and energy utilization. Understanding how they function is important for biomedical science and requires a full description of their notorious propensity for specificity and promiscuity. The bacterial P450cam is an unusual example, having the most well characterized chemical mechanism of all of the forms. It also undergoes an increasingly well characterized structural change upon substrate binding, which may be similar to to that displayed by some, but not all forms of P450. Finally, P450cam is one of the rare forms that have a strict requirement for a particular electron donor, putidaredoxin (pdx). Pdx provides the required electrons for enzyme turnover, but it also induces specific changes in the enzyme to allow enzyme turnover, long known as its effector role. This review summarizes recent crystallographic and double electron–electron resonance studies that have revealed the effects of substrate and pdx binding on the structure of P450cam. We describe an emerging idea for how pdx exerts its effector function by inducing a conformational change in the enzyme. This change then propagates to the active site to enable cleavage of the ferric–hydroperoxy bond during catalysis, and appears to provide a very elegant approach for P450cam to attain both high efficiency and protection from oxidative damage.
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Affiliation(s)
- David B. Goodin
- University of California Davis, Department of Chemistry One Shields Ave Davis CA 95616 USA
| | - Shih-Wei Chuo
- University of California Davis, Department of Chemistry One Shields Ave Davis CA 95616 USA
| | - Shu-Hao Liou
- Research Group EPR Spectroscopy, Max-Planck-Institute for Biophysical Chemistry Göttingen 37077 Germany
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7
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Structure of cytochrome P450 2B4 with an acetate ligand and an active site hydrogen bond network similar to oxyferrous P450cam. J Inorg Biochem 2018; 185:17-25. [PMID: 29730233 DOI: 10.1016/j.jinorgbio.2018.04.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 04/19/2018] [Accepted: 04/21/2018] [Indexed: 02/03/2023]
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8
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Mak PJ, Denisov IG. Spectroscopic studies of the cytochrome P450 reaction mechanisms. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2018; 1866:178-204. [PMID: 28668640 PMCID: PMC5709052 DOI: 10.1016/j.bbapap.2017.06.021] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 06/22/2017] [Indexed: 10/19/2022]
Abstract
The cytochrome P450 monooxygenases (P450s) are thiolate heme proteins that can, often under physiological conditions, catalyze many distinct oxidative transformations on a wide variety of molecules, including relatively simple alkanes or fatty acids, as well as more complex compounds such as steroids and exogenous pollutants. They perform such impressive chemistry utilizing a sophisticated catalytic cycle that involves a series of consecutive chemical transformations of heme prosthetic group. Each of these steps provides a unique spectral signature that reflects changes in oxidation or spin states, deformation of the porphyrin ring or alteration of dioxygen moieties. For a long time, the focus of cytochrome P450 research was to understand the underlying reaction mechanism of each enzymatic step, with the biggest challenge being identification and characterization of the powerful oxidizing intermediates. Spectroscopic methods, such as electronic absorption (UV-Vis), electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR), electron nuclear double resonance (ENDOR), Mössbauer, X-ray absorption (XAS), and resonance Raman (rR), have been useful tools in providing multifaceted and detailed mechanistic insights into the biophysics and biochemistry of these fascinating enzymes. The combination of spectroscopic techniques with novel approaches, such as cryoreduction and Nanodisc technology, allowed for generation, trapping and characterizing long sought transient intermediates, a task that has been difficult to achieve using other methods. Results obtained from the UV-Vis, rR and EPR spectroscopies are the main focus of this review, while the remaining spectroscopic techniques are briefly summarized. This article is part of a Special Issue entitled: Cytochrome P450 biodiversity and biotechnology, edited by Erika Plettner, Gianfranco Gilardi, Luet Wong, Vlada Urlacher, Jared Goldstone.
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Affiliation(s)
- Piotr J Mak
- Department of Chemistry, Saint Louis University, St. Louis, MO, United States.
| | - Ilia G Denisov
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL, United States.
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9
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Batabyal D, Richards LS, Poulos TL. Effect of Redox Partner Binding on Cytochrome P450 Conformational Dynamics. J Am Chem Soc 2017; 139:13193-13199. [PMID: 28823160 DOI: 10.1021/jacs.7b07656] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Previous crystal structures of cytochrome P450cam complexed with its redox partner, putidaredoxin (Pdx), shows that P450cam adopts the open conformation. It has been hypothesized that the Pdx-induced shift toward the open state frees the essential Asp251 from salt bridges with Arg186 and Lys178 so that Asp251 can participate in a proton relay network required for O2 activation. This in part explains why P450cam has such a strict requirement for Pdx. One problem with this view is that looser substrate-protein interactions in the open state may not be compatible with the observed regio- and stereoselective hydroxylation. In the present study, molecular dynamics simulations show that Pdx binding favors a conformation that stabilizes the active site and decreases camphor mobility yet retains a partially open conformation compatible with the required proton relay network. The R186A mutant which frees Asp251 in the absence of Pdx retains good enzyme activity, and the crystal structure shows that product, 5-exo-hydroxycamphor, is bound. This indicates that rupture of the Asp251-Arg186 relaxes selectivity with respect to source of electrons and enables X-ray generated reducing equivalents to support substrate hydroxylation. These combined computational and experimental results are consistent with the proposed role of Pdx in assisting the release of Asp251 from ion pairs so that it can participate in proton-coupled electron transfer.
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Affiliation(s)
- Dipanwita Batabyal
- Departments of Molecular Biology and Biochemistry, Pharmaceutical Sciences, and Chemistry, University of California , Irvine, California 92697-3900, United States
| | - Logan S Richards
- Departments of Molecular Biology and Biochemistry, Pharmaceutical Sciences, and Chemistry, University of California , Irvine, California 92697-3900, United States
| | - Thomas L Poulos
- Departments of Molecular Biology and Biochemistry, Pharmaceutical Sciences, and Chemistry, University of California , Irvine, California 92697-3900, United States
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10
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Batabyal D, Lewis-Ballester A, Yeh SR, Poulos TL. A Comparative Analysis of the Effector Role of Redox Partner Binding in Bacterial P450s. Biochemistry 2016; 55:6517-6523. [PMID: 27808504 DOI: 10.1021/acs.biochem.6b00913] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The camphor monooxygenase, cytochrome P450cam, exhibits a strict requirement for its own redox partner, putidaredoxin (Pdx), a two-iron-sulfur ferredoxin. The closest homologue to P450cam, CYP101D1, is structurally very similar, uses a similar redox partner, and exhibits nearly identical enzymatic properties in the monooxygenation of camphor to give the same single 5-exo-hydroxy camphor product. However, CYP101D1 does not strictly require its own ferredoxin (Arx) for activity because Pdx can support CYP101D1 catalysis but Arx cannot support P450cam catalysis. We have further examined the differences between these two P450s by determining the effect of spin equilibrium, redox properties, and stability of oxygen complexes. We find that Arx shifts the spin state equilibrium toward high-spin, which is the opposite of the effect of Pdx on P450cam. In both P450s, redox partner binding destabilizes the oxy-P450 complex but this effect is much weaker with CYP101D1. In addition, resonance Raman data show that structural perturbations observed in P450cam upon addition of Pdx are absent in CYP101D1. These data indicate that Arx does not play the same effector role in catalysis as Pdx does with P450cam. The most relevant structural difference between these two P450s centers on a catalytically important Asp residue required for proton-coupled electron transfer. We postulate that with P450cam larger Pdx-assisted motions are required to free this Asp for catalysis while the smaller number of restrictions in CYP101D1 precludes the need for redox partner-assisted structural changes.
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Affiliation(s)
- Dipanwita Batabyal
- Departments of Molecular Biology and Biochemistry, Chemistry, and Pharmaceutical Sciences, University of California , Irvine, California 92697, United States
| | - Ariel Lewis-Ballester
- Department of Physiology and Biophysics, Albert Einstein College of Medicine , 1300 Morris Park Avenue, Bronx, New York 10461, United States
| | - Syun-Ru Yeh
- Department of Physiology and Biophysics, Albert Einstein College of Medicine , 1300 Morris Park Avenue, Bronx, New York 10461, United States
| | - Thomas L Poulos
- Departments of Molecular Biology and Biochemistry, Chemistry, and Pharmaceutical Sciences, University of California , Irvine, California 92697, United States
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11
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Bhupathiraju NVSDK, Rizvi W, Batteas JD, Drain CM. Fluorinated porphyrinoids as efficient platforms for new photonic materials, sensors, and therapeutics. Org Biomol Chem 2016; 14:389-408. [PMID: 26514229 PMCID: PMC6180335 DOI: 10.1039/c5ob01839k] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Porphyrinoids are robust heterocyclic dyes studied extensively for their applications in medicine and as photonic materials because of their tunable photophysical properties, diverse means of modifying the periphery, and the ability to chelate most transition metals. Commercial applications include their use as phthalocyanine dyes in optical discs, porphyrins in photodynamic therapy, and as oxygen sensors. Most applications of these dyes require exocyclic moieties to improve solubility, target diseases, modulate photophysical properties, or direct the self-organization into architectures with desired photonic properties. The synthesis of the porphyrinoid depends on the desired application, but the de novo synthesis often involves several steps, is time consuming, and results in low isolated yields. Thus, the application of core porphyrinoid platforms that can be rapidly and efficiently modified to evaluate new molecular architectures allows researchers to focus on the design concepts rather than the synthesis methods, and opens porphyrinoid chemistry to a broader scientific community. We have focused on several widely available, commercially viable porphyrinoids as platforms: meso-perfluorophenylporphyrin, perfluorophthalocyanine, and meso-perfluorophenylcorrole. The perfluorophenylporphyrin is readily converted to the chlorin, bacteriochlorin, and isobacteriochlorin. Derivatives of all six of these core platforms can be efficiently and controllably made via mild nucleophilic aromatic substitution reactions using primary S, N, and O nucleophiles bearing a wide variety of functional groups. The remaining fluoro groups enhance the photo and oxidative stability of the dyes and can serve as spectroscopic signatures to characterize the compounds or in imaging applications using (19)F NMR. This review provides an overview of the chemistry of fluorinated porphyrinoids that are being used as a platform to create libraries of photo-active compounds for applications in medicine and materials.
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Affiliation(s)
- N V S Dinesh K Bhupathiraju
- Department of Chemistry and Biochemistry, Hunter College and Graduate Center of the City University of New York (CUNY), 695 Park Avenue, New York, NY 10065, USA
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12
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Kiss FM, Khatri Y, Zapp J, Bernhardt R. Identification of new substrates for the CYP106A1-mediated 11-oxidation and investigation of the reaction mechanism. FEBS Lett 2015; 589:2320-6. [DOI: 10.1016/j.febslet.2015.07.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 07/09/2015] [Accepted: 07/13/2015] [Indexed: 10/23/2022]
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13
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Khatri Y, Luthra A, Duggal R, Sligar SG. Kinetic solvent isotope effect in steady-state turnover by CYP19A1 suggests involvement of Compound 1 for both hydroxylation and aromatization steps. FEBS Lett 2014; 588:3117-22. [PMID: 24997347 DOI: 10.1016/j.febslet.2014.06.050] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 06/03/2014] [Accepted: 06/13/2014] [Indexed: 10/25/2022]
Abstract
CYP19A1, or human aromatase catalyzes the conversion of androgens to estrogens in a three-step reaction through the formation of 19-hydroxy and 19-aldehyde intermediates. While the first two steps of hydroxylation are thought to proceed through a high-valent iron-oxo species, controversy exists surrounding the identity of the reaction intermediate that catalyzes the lyase and aromatization reaction. We investigated the kinetic isotope effect on the steady-state turnover of Nanodisc-incorporated human CYP19A1 to explore the mechanisms of this reaction. Our experiments reveal a significant (∼ 2.5) kinetic solvent isotope effect for the C10-C19 lyase reaction, similar to that of the first two hydroxylation steps (2.7 and 1.2). These data implicate the involvement of Compound 1 as a reactive intermediate in the final aromatization step of CYP19A1.
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Affiliation(s)
- Yogan Khatri
- Department of Biochemistry, University of Illinois Urbana-Champaign, 505 S. Goodwin Avenue, Urbana, IL 61801, United States
| | - Abhinav Luthra
- Department of Biochemistry, University of Illinois Urbana-Champaign, 505 S. Goodwin Avenue, Urbana, IL 61801, United States
| | - Ruchia Duggal
- Department of Biochemistry, University of Illinois Urbana-Champaign, 505 S. Goodwin Avenue, Urbana, IL 61801, United States
| | - Stephen G Sligar
- Department of Biochemistry, University of Illinois Urbana-Champaign, 505 S. Goodwin Avenue, Urbana, IL 61801, United States.
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Batabyal D, Poulos TL. Crystal structures and functional characterization of wild-type CYP101D1 and its active site mutants. Biochemistry 2013; 52:8898-906. [PMID: 24261604 DOI: 10.1021/bi401330c] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although CYP101D1 and P450cam catalyze the same reaction at similar rates and share strikingly similar active site architectures, there are significant functional differences. CYP101D1 thus provides an opportunity to probe what structural and functional features must be shared and what features can differ but maintain the high catalytic efficiency. Crystal structures of the cyanide complex of wild-type CYP101D1 and it active site mutants, D259N and T260A, have been determined. The conformational changes in CYP101D1 upon cyanide binding are very similar to those of P450cam, indicating a similar mechanism for proton delivery during oxygen activation using solvent-assisted proton transfer. The D259N-CN- complex shows a perturbed solvent structure compared to that of the wild type, which is similar to what was observed in the oxy complex of the corresonding D251N mutant in P450cam. As in P450cam, the T260A mutant is highly uncoupled while the D259N mutant gives barely detectable activity. Despite these similarities, CYP101D1 is able to use the P450cam redox partners while P450cam cannot use the CYP101D1 redox partners. Thus, the strict requirement of P450cam for its own redox partner is relaxed in CYP101D1. Differences in the local environment of the essential Asp (Asp259 in CYP101D1) provide a strucutral basis for understanding these functional differences.
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Affiliation(s)
- Dipanwita Batabyal
- Departments of Molecular Biology and Biochemistry, Chemistry, and Pharmaceutical Sciences, University of California , Irvine, California 92697-3900, United States
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15
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Gregory MC, Denisov IG, Grinkova YV, Khatri Y, Sligar SG. Kinetic solvent isotope effect in human P450 CYP17A1-mediated androgen formation: evidence for a reactive peroxoanion intermediate. J Am Chem Soc 2013; 135:16245-7. [PMID: 24160919 DOI: 10.1021/ja4086403] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Human steroid hormone biosynthesis is the result of a complex series of chemical transformations operating on cholesterol, with key steps mediated by members of the cytochrome P450 superfamily. In the formation of the male hormone dehydroepiandrosterone, pregnenolone is first hydroxylated by P450 CYP17A1 at the 17-carbon, followed a second round of catalysis by the same enzyme that cleaves the C17-C20 bond, releasing acetic acid and the 17-keto product. In order to explore the mechanism of this C-C "lyase" activity, we investigated the kinetic isotope effect on the steady-state turnover of Nanodisc-incorporated CYP17A1. Our experiments revealed the expected small positive (~1.3) isotope effect for the hydroxylase chemistry. However, a surprising result was the large inverse isotope effect (~0.39) observed for the C-C bond cleavage activity. These results strongly suggest that the P450 reactive intermediate involved in this latter step is an iron-bound ferric peroxoanion.
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Affiliation(s)
- Michael C Gregory
- Department of Biochemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
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