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Kumar N, He J, Rusling JF. Electrochemical transformations catalyzed by cytochrome P450s and peroxidases. Chem Soc Rev 2023; 52:5135-5171. [PMID: 37458261 DOI: 10.1039/d3cs00461a] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/01/2023]
Abstract
Cytochrome P450s (Cyt P450s) and peroxidases are enzymes featuring iron heme cofactors that have wide applicability as biocatalysts in chemical syntheses. Cyt P450s are a family of monooxygenases that oxidize fatty acids, steroids, and xenobiotics, synthesize hormones, and convert drugs and other chemicals to metabolites. Peroxidases are involved in breaking down hydrogen peroxide and can oxidize organic compounds during this process. Both heme-containing enzymes utilize active FeIVO intermediates to oxidize reactants. By incorporating these enzymes in stable thin films on electrodes, Cyt P450s and peroxidases can accept electrons from an electrode, albeit by different mechanisms, and catalyze organic transformations in a feasible and cost-effective way. This is an advantageous approach, often called bioelectrocatalysis, compared to their biological pathways in solution that require expensive biochemical reductants such as NADPH or additional enzymes to recycle NADPH for Cyt P450s. Bioelectrocatalysis also serves as an ex situ platform to investigate metabolism of drugs and bio-relevant chemicals. In this paper we review biocatalytic electrochemical reactions using Cyt P450s including C-H activation, S-oxidation, epoxidation, N-hydroxylation, and oxidative N-, and O-dealkylation; as well as reactions catalyzed by peroxidases including synthetically important oxidations of organic compounds. Design aspects of these bioelectrocatalytic reactions are presented and discussed, including enzyme film formation on electrodes, temperature, pH, solvents, and activation of the enzymes. Finally, we discuss challenges and future perspective of these two important bioelectrocatalytic systems.
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Affiliation(s)
- Neeraj Kumar
- Department of Chemistry, University of Connecticut, Storrs, CT 06269-3136, USA.
| | - Jie He
- Department of Chemistry, University of Connecticut, Storrs, CT 06269-3136, USA.
- Institute of Materials Science, University of Connecticut, Storrs, CT 06269-3136, USA
| | - James F Rusling
- Department of Chemistry, University of Connecticut, Storrs, CT 06269-3136, USA.
- Institute of Materials Science, University of Connecticut, Storrs, CT 06269-3136, USA
- Department of Surgery and Neag Cancer Center, Uconn Health, Farmington, CT 06030, USA
- School of Chemistry, National University of Ireland at Galway, Galway, Ireland
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2
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Evolution of Cytochrome P450 Enzymes and Their Redox Partners in Archaea. Int J Mol Sci 2023; 24:ijms24044161. [PMID: 36835573 PMCID: PMC9962201 DOI: 10.3390/ijms24044161] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/16/2023] [Accepted: 02/17/2023] [Indexed: 02/22/2023] Open
Abstract
Cytochrome P450 monooxygenases (CYPs/P450s) and their redox partners, ferredoxins, are ubiquitous in organisms. P450s have been studied in biology for over six decades owing to their distinct catalytic activities, including their role in drug metabolism. Ferredoxins are ancient proteins involved in oxidation-reduction reactions, such as transferring electrons to P450s. The evolution and diversification of P450s in various organisms have received little attention and no information is available for archaea. This study is aimed at addressing this research gap. Genome-wide analysis revealed 1204 P450s belonging to 34 P450 families and 112 P450 subfamilies, where some families and subfamilies are expanded in archaea. We also identified 353 ferredoxins belonging to the four types 2Fe-2S, 3Fe-4S, 7Fe-4S and 2[4Fe-4S] in 40 archaeal species. We found that bacteria and archaea shared the CYP109, CYP147 and CYP197 families, as well as several ferredoxin subtypes, and that these genes are co-present on archaeal plasmids and chromosomes, implying the plasmid-mediated lateral transfer of these genes from bacteria to archaea. The absence of ferredoxins and ferredoxin reductases in the P450 operons suggests that the lateral transfer of these genes is independent. We present different scenarios for the evolution and diversification of P450s and ferredoxins in archaea. Based on the phylogenetic analysis and high affinity to diverged P450s, we propose that archaeal P450s could have diverged from CYP109, CYP147 and CYP197. Based on this study's results, we propose that all archaeal P450s are bacterial in origin and that the original archaea had no P450s.
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3
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Behrendorff JBYH. Reductive Cytochrome P450 Reactions and Their Potential Role in Bioremediation. Front Microbiol 2021; 12:649273. [PMID: 33936006 PMCID: PMC8081977 DOI: 10.3389/fmicb.2021.649273] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 03/22/2021] [Indexed: 11/13/2022] Open
Abstract
Cytochrome P450 enzymes, or P450s, are haem monooxygenases renowned for their ability to insert one atom from molecular oxygen into an exceptionally broad range of substrates while reducing the other atom to water. However, some substrates including many organohalide and nitro compounds present little or no opportunity for oxidation. Under hypoxic conditions P450s can perform reductive reactions, contributing electrons to drive reductive elimination reactions. P450s can catalyse dehalogenation and denitration of a range of environmentally persistent pollutants including halogenated hydrocarbons and nitroamine explosives. P450-mediated reductive dehalogenations were first discovered in the context of human pharmacology but have since been observed in a variety of organisms. Additionally, P450-mediated reductive denitration of synthetic explosives has been discovered in bacteria that inhabit contaminated soils. This review will examine the distribution of P450-mediated reductive dehalogenations and denitrations in nature and discuss synthetic biology approaches to developing P450-based reagents for bioremediation.
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Affiliation(s)
- James B. Y. H. Behrendorff
- Centre for Agriculture and the Bioeconomy, Queensland University of Technology, Brisbane, QLD, Australia
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Synthetic Biology Future Science Platform, Canberra, ACT, Australia
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Hollmann F, Opperman DJ, Paul CE. Biocatalytic Reduction Reactions from a Chemist's Perspective. Angew Chem Int Ed Engl 2021; 60:5644-5665. [PMID: 32330347 PMCID: PMC7983917 DOI: 10.1002/anie.202001876] [Citation(s) in RCA: 84] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Indexed: 11/09/2022]
Abstract
Reductions play a key role in organic synthesis, producing chiral products with new functionalities. Enzymes can catalyse such reactions with exquisite stereo-, regio- and chemoselectivity, leading the way to alternative shorter classical synthetic routes towards not only high-added-value compounds but also bulk chemicals. In this review we describe the synthetic state-of-the-art and potential of enzymes that catalyse reductions, ranging from carbonyl, enone and aromatic reductions to reductive aminations.
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Affiliation(s)
- Frank Hollmann
- Department of BiotechnologyDelft University of TechnologyVan der Maasweg 92629 HZDelftThe Netherlands
- Department of BiotechnologyUniversity of the Free State205 Nelson Mandela DriveBloemfontein9300South Africa
| | - Diederik J. Opperman
- Department of BiotechnologyUniversity of the Free State205 Nelson Mandela DriveBloemfontein9300South Africa
| | - Caroline E. Paul
- Department of BiotechnologyDelft University of TechnologyVan der Maasweg 92629 HZDelftThe Netherlands
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5
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Hollmann F, Opperman DJ, Paul CE. Biokatalytische Reduktionen aus der Sicht eines Chemikers. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202001876] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Frank Hollmann
- Department of Biotechnology Delft University of Technology Van der Maasweg 9 2629 HZ Delft Niederlande
- Department of Biotechnology University of the Free State 205 Nelson Mandela Drive Bloemfontein 9300 Südafrika
| | - Diederik J. Opperman
- Department of Biotechnology University of the Free State 205 Nelson Mandela Drive Bloemfontein 9300 Südafrika
| | - Caroline E. Paul
- Department of Biotechnology Delft University of Technology Van der Maasweg 9 2629 HZ Delft Niederlande
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6
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Li RJ, Zhang Z, Acevedo-Rocha CG, Zhao J, Li A. Biosynthesis of organic molecules via artificial cascade reactions based on cytochrome P450 monooxygenases. GREEN SYNTHESIS AND CATALYSIS 2020. [DOI: 10.1016/j.gresc.2020.05.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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Meißner G, Feist M, Braun T, Kemnitz E. Selective reduction of a C Cl bond in halomethanes with Et3GeH at nanoscopic Lewis acidic Aluminium fluoride. J Organomet Chem 2017. [DOI: 10.1016/j.jorganchem.2017.04.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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8
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Segal HM, Spatzal T, Hill MG, Udit AK, Rees DC. Electrochemical and structural characterization of Azotobacter vinelandii flavodoxin II. Protein Sci 2017; 26:1984-1993. [PMID: 28710816 PMCID: PMC5606536 DOI: 10.1002/pro.3236] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 07/08/2017] [Accepted: 07/10/2017] [Indexed: 01/07/2023]
Abstract
Azotobacter vinelandii flavodoxin II serves as a physiological reductant of nitrogenase, the enzyme system mediating biological nitrogen fixation. Wildtype A. vinelandii flavodoxin II was electrochemically and crystallographically characterized to better understand the molecular basis for this functional role. The redox properties were monitored on surfactant-modified basal plane graphite electrodes, with two distinct redox couples measured by cyclic voltammetry corresponding to reduction potentials of -483 ± 1 mV and -187 ± 9 mV (vs. NHE) in 50 mM potassium phosphate, 150 mM NaCl, pH 7.5. These redox potentials were assigned as the semiquinone/hydroquinone couple and the quinone/semiquinone couple, respectively. This study constitutes one of the first applications of surfactant-modified basal plane graphite electrodes to characterize the redox properties of a flavodoxin, thus providing a novel electrochemical method to study this class of protein. The X-ray crystal structure of the flavodoxin purified from A. vinelandii was solved at 1.17 Å resolution. With this structure, the native nitrogenase electron transfer proteins have all been structurally characterized. Docking studies indicate that a common binding site surrounding the Fe-protein [4Fe:4S] cluster mediates complex formation with the redox partners Mo-Fe protein, ferredoxin I, and flavodoxin II. This model supports a mechanistic hypothesis that electron transfer reactions between the Fe-protein and its redox partners are mutually exclusive.
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Affiliation(s)
- Helen M Segal
- Division of Chemistry and Chemical Engineering, Howard Hughes Medical Institute, California Institute of Technology, Pasadena, California, 91125
| | - Thomas Spatzal
- Division of Chemistry and Chemical Engineering, Howard Hughes Medical Institute, California Institute of Technology, Pasadena, California, 91125
| | - Michael G Hill
- Division of Chemistry, Occidental College, Los Angeles, California, 90041
| | - Andrew K Udit
- Division of Chemistry, Occidental College, Los Angeles, California, 90041
| | - Douglas C Rees
- Division of Chemistry and Chemical Engineering, Howard Hughes Medical Institute, California Institute of Technology, Pasadena, California, 91125
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9
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Harris KL, Thomson RES, Strohmaier SJ, Gumulya Y, Gillam EMJ. Determinants of thermostability in the cytochrome P450 fold. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017; 1866:97-115. [PMID: 28822812 DOI: 10.1016/j.bbapap.2017.08.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 07/19/2017] [Accepted: 08/07/2017] [Indexed: 10/19/2022]
Abstract
Cytochromes P450 are found throughout the biosphere in a wide range of environments, serving a multitude of physiological functions. The ubiquity of the P450 fold suggests that it has been co-opted by evolution many times, and likely presents a useful compromise between structural stability and conformational flexibility. The diversity of substrates metabolized and reactions catalyzed by P450s makes them attractive starting materials for use as biocatalysts of commercially useful reactions. However, process conditions impose different requirements on enzymes to those in which they have evolved naturally. Most natural environments are relatively mild, and therefore most P450s have not been selected in Nature for the ability to withstand temperatures above ~40°C, yet industrial processes frequently require extended incubations at much higher temperatures. Thus, there has been considerable interest and effort invested in finding or engineering thermostable P450 systems. Numerous P450s have now been identified in thermophilic organisms and analysis of their structures provides information as to mechanisms by which the P450 fold can be stabilized. In addition, protein engineering, particularly by directed or artificial evolution, has revealed mutations that serve to stabilize particular mesophilic enzymes of interest. Here we review the current understanding of thermostability as it applies to the P450 fold, gleaned from the analysis of P450s characterized from thermophilic organisms and the parallel engineering of mesophilic forms for greater thermostability. We then present a perspective on how this information might be used to design stable P450 enzymes for industrial application. 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)
- Kurt L Harris
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia 4072, Australia
| | - Raine E S Thomson
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia 4072, Australia
| | - Silja J Strohmaier
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia 4072, Australia
| | - Yosephine Gumulya
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia 4072, Australia
| | - Elizabeth M J Gillam
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia 4072, Australia.
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10
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Ducharme J, Auclair K. Use of bioconjugation with cytochrome P450 enzymes. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017. [PMID: 28625736 DOI: 10.1016/j.bbapap.2017.06.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Bioconjugation, defined as chemical modification of biomolecules, is widely employed in biological and biophysical studies. It can expand functional diversity and enable applications ranging from biocatalysis, biosensing and even therapy. This review summarizes how chemical modifications of cytochrome P450 enzymes (P450s or CYPs) have contributed to improving our understanding of these enzymes. Genetic modifications of P450s have also proven very useful but are not covered in this review. Bioconjugation has served to gain structural information and investigate the mechanism of P450s via photoaffinity labeling, mechanism-based inhibition (MBI) and fluorescence studies. P450 surface acetylation and protein cross-linking have contributed to the investigation of protein complexes formation involving P450 and its redox partner or other P450 enzymes. Finally, covalent immobilization on polymer surfaces or electrodes has benefited the areas of biocatalysis and biosensor design. 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)
- Julie Ducharme
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
| | - Karine Auclair
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada.
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11
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Zhang C, Li J, Yang B, He F, Yang SY, Yu XQ, Wang Q. Enhanced turnover rate and enantioselectivity in the asymmetric epoxidation of styrene by new T213G mutants of CYP 119. RSC Adv 2014. [DOI: 10.1039/c4ra04626a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
New CYP 119 T213G mutants were constructed and characterized. Introduction of T213G mutation into the wild-type CYP 119 enhances the turnover rate for the styrene epoxidation to 346.2 min−1, and the double T213G/T214V mutant improves the ratio of the S- and R-enantiomers of the epoxide products to 5.8. The molecular docking results support our initial design and experimental data.
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Affiliation(s)
- Chun Zhang
- Department of Medicinal Chemistry
- Luzhou Medical College
- Luzhou 646000, China
| | - Jing Li
- Department of Medicinal Chemistry
- Luzhou Medical College
- Luzhou 646000, China
| | - Bo Yang
- State Key Laboratory of Biotherapy
- West China Hospital
- Sichuan University
- Chengdu 610041, China
| | - Fang He
- Department of Medicinal Chemistry
- Luzhou Medical College
- Luzhou 646000, China
| | - Sheng-Yong Yang
- State Key Laboratory of Biotherapy
- West China Hospital
- Sichuan University
- Chengdu 610041, China
| | - Xiao-Qi Yu
- College of Chemistry
- Sichuan University
- Chengdu 610064, China
| | - Qin Wang
- Department of Medicinal Chemistry
- Luzhou Medical College
- Luzhou 646000, China
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12
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Electrochemistry of mammalian cytochrome P450 2B4 indicates tunable thermodynamic parameters in surfactant films. J Inorg Biochem 2013; 129:30-4. [PMID: 24013063 DOI: 10.1016/j.jinorgbio.2013.07.039] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 07/28/2013] [Accepted: 07/29/2013] [Indexed: 11/23/2022]
Abstract
Electrochemical methods continue to present an attractive means for achieving in vitro biocatalysis with cytochromes P450; however understanding fully the nature of electrode-bound P450 remains elusive. Herein we report thermodynamic parameters using electrochemical analysis of full-length mammalian microsomal cytochrome P450 2B4 (CYP 2B4) in didodecyldimethylammonium bromide (DDAB) surfactant films. Electronic absorption spectra of CYP 2B4-DDAB films on silica slides reveal an absorption maximum at 418nm, characteristic of low-spin, six-coordinate, water-ligated Fe(III) heme in P450. The Fe(III/II) and Fe(II/I) redox couples (E1/2) of substrate-free CYP 2B4 measured by cyclic voltammetry are -0.23V and -1.02V (vs. SCE, or 14mV and -776mV vs. NHE) at 21°C. The standard heterogeneous rate constant for electron transfer from the electrode to the heme for the Fe(III/II) couple was estimated at 170s(-1). Experiments indicate that the system is capable of catalytic reduction of dioxygen, however substrate oxidation was not observed. From the variation of E1/2 with temperature (18-40°C), we have measured entropy and enthalpy changes that accompany heme reduction, -151Jmol(-1)K(-1) and -46kJmol(-1), respectfully. The corresponding entropy and enthalpy values are less for the six-coordinate low-spin, imidazole-ligated enzyme (-59Jmol(-1)K(-1) and -18kJmol(-1)), consistent with limited conformational changes upon reduction. These thermodynamic parameters are comparable to those measured for bacterial P450 from Bacillus megaterium (CYP BM3), confirming our prior reports that the surfactant environment exerts a strong influence on the redox properties of the heme.
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Jett JE, Lederman D, Wollenberg LA, Li D, Flora DR, Bostick CD, Tracy TS, Gannett PM. Measurement of electron transfer through cytochrome P450 protein on nanopillars and the effect of bound substrates. J Am Chem Soc 2013; 135:3834-40. [PMID: 23427827 PMCID: PMC3876957 DOI: 10.1021/ja309104g] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Electron transfer in cytochrome P450 enzymes is a fundamental process for activity. It is difficult to measure electron transfer in these enzymes because under the conditions typically used they exist in a variety of states. Using nanotechnology-based techniques, gold conducting nanopillars were constructed in an indexed array. The P450 enzyme CYP2C9 was attached to each of these nanopillars, and conductivity measurements made using conducting probe atomic force microscopy under constant force conditions. The conductivity measurements were made on CYP2C9 alone and with bound substrates, a bound substrate-effector pair, and a bound inhibitor. Fitting of the data with the Poole-Frenkel model indicates a correlation between the barrier height for electron transfer and the ease of CYP2C9-mediated metabolism of the bound substrates, though the spin state of iron is not well correlated. The approach described here should have broad application to the measurement of electron transfer in P450 enzymes and other metalloenzymes.
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Affiliation(s)
- John E. Jett
- West Virginia University, Basic Pharmaceutical Sciences, Morgantown, WV 26506-9530
| | - David Lederman
- West Virginia University, Department of Physics, Morgantown, WV 26506-6315
| | - Lance A. Wollenberg
- West Virginia University, Basic Pharmaceutical Sciences, Morgantown, WV 26506-9530
| | - Debin Li
- West Virginia University, Department of Physics, Morgantown, WV 26506-6315
| | - Darcy R. Flora
- University of Minnesota, College of Pharmacy, Minneapolis, MN, 55455
| | | | - Timothy S. Tracy
- University of Kentucky, College of Pharmacy, Lexington, KY 40536
| | - Peter M. Gannett
- West Virginia University, Basic Pharmaceutical Sciences, Morgantown, WV 26506-9530
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Romańczyk PP, Radoń M, Noga K, Kurek SS. Autocatalytic cathodic dehalogenation triggered by dissociative electron transfer through a C–H⋯O hydrogen bond. Phys Chem Chem Phys 2013; 15:17522-36. [DOI: 10.1039/c3cp52933a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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15
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De Spiegeleer B, Van Dorpe S, Vergote V, Wynendaele E, Pauwels E, Van De Wiele C, Garcia-Solis P, Solis-Sainz JC. In vitro metabolic stability of iodinated obestatin peptides. Peptides 2012; 33:272-8. [PMID: 22222609 DOI: 10.1016/j.peptides.2011.12.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 12/18/2011] [Accepted: 12/18/2011] [Indexed: 10/14/2022]
Abstract
Different iodinated mouse obestatin peptides have been characterized toward their in vitro stability in the main metabolic compartments plasma, liver and kidney. Using HPLC-UV for quantification, significant differences in the degradation kinetics of the iodinated peptides, arising from both enzymatic proteolysis and dehalogenation, were found when compared to the native, unmodified peptide. HPLC-MS/MS analysis demonstrated that the cleavage sites were dependent upon the biological matrix and the location of the amino acid residue incorporating the iodine atom(s). The degrading proteases were found to target peptide bonds further away from the iodine incorporation, while proteolytic cleavages of nearby peptide bonds were more limited. Diiodinated amino acid residue containing peptides were found to be more susceptible to deiodination than the mono-iodinated derivative. In plasma, the percentage of peptide degradation solely attributed to deiodinase activity after 20 min incubation reached up to 25% for 2,5-diiodo-H(19)-obestatin compared to 20% and only 3% for (3,5-diiodo-Y(16))- and (3-iodo-Y(16)) obestatin, respectively. Hence, our results demonstrate that the different iodinated peptides pose significantly different metabolization properties and thus, also different biological activities are expected for peptides upon iodination.
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Affiliation(s)
- Bart De Spiegeleer
- Drug Quality and Registration Group, Faculty of Pharmaceutical Sciences, Ghent University, Harelbekestraat 72, B-9000 Ghent, Belgium.
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Ferrero VEV, Di Nardo G, Catucci G, Sadeghi SJ, Gilardi G. Fluorescence detection of ligand binding to labeled cytochrome P450BM3. Dalton Trans 2012; 41:2018-25. [DOI: 10.1039/c1dt11437a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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17
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Krishnan S, Schenkman JB, Rusling JF. Bioelectronic delivery of electrons to cytochrome P450 enzymes. J Phys Chem B 2011; 115:8371-80. [PMID: 21591685 DOI: 10.1021/jp201235m] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cytochrome P450s (cyt P450s) are the major oxidative enzymes in human oxidative metabolism of drugs and xenobiotic chemicals. In nature, the iron heme cyt P450s utilize oxygen and electrons delivered from NADPH by a reductase enzyme to oxidize substrates stereo- and regioselectively. Significant research has been directed toward achieving these events electrochemically. This Feature Article discusses the direct electrochemistry of cyt P450s in thin films and the utilization of such films for electrochemically driven biocatalysis. Maintaining and confirming structural integrity and catalytic activity of cyt P450s in films is an essential feature of these efforts. We highlight here our efforts to elucidate the influence of iron heme spin state and secondary structure of human cyt P450s on voltammetric and biocatalytic properties, using methodologies to quantitatively describe the dynamics of these processes in thin films. We also describe the first cyt P450/reductase films that accurately mimic the natural biocatalytic pathway and show how they can be used with voltammetry to elucidate key mechanistic features. Such bioelectronic cyt P450 systems have high value for future drug development, toxicity screening, fundamental investigations, and chemical synthesis systems.
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Affiliation(s)
- Sadagopan Krishnan
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
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Rabe KS, Erkelenz M, Kiko K, Niemeyer CM. Peroxidase activity of bacterial cytochrome P450 enzymes: Modulation by fatty acids and organic solvents. Biotechnol J 2010; 5:891-9. [DOI: 10.1002/biot.201000028] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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19
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Jia Y, Zhang H, Wu L, Lv Y, Hou X. A new cataluminescence sensor for carbon tetrachloride using its catalytic reduction by hydrogen on palladium/carbon surface. Microchem J 2010. [DOI: 10.1016/j.microc.2010.02.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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20
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Hollmann F, Arends I, Buehler K. Biocatalytic Redox Reactions for Organic Synthesis: Nonconventional Regeneration Methods. ChemCatChem 2010. [DOI: 10.1002/cctc.201000069] [Citation(s) in RCA: 206] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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21
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Krishnan S, Abeykoon A, Schenkman JB, Rusling JF. Control of electrochemical and ferryloxy formation kinetics of cyt P450s in polyion films by heme iron spin state and secondary structure. J Am Chem Soc 2010; 131:16215-24. [PMID: 19886700 DOI: 10.1021/ja9065317] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Voltammetry of cytochrome P450 (cyt P450) enzymes in ultrathin films with polyions was related for the first time to electronic and secondary structure. Heterogeneous electron transfer (hET) rate constants for reduction of the cyt P450s depended on heme iron spin state, with low spin cyt P450cam giving a value 40-fold larger than high spin human cyt P450 1A2, with mixed spin human P450 cyt 2E1 at an intermediate value. Asymmetric reduction-oxidation peak separations with increasing scan rates were explained by simulations featuring faster oxidation than reduction. Results are consistent with a square scheme in which oxidized and reduced forms of cyt P450s each participate in rapid conformational equilibria. Rate constants for oxidation of ferric cyt P450s in films by t-butyl hydroperoxide to active ferryloxy cyt P450s from rotating disk voltammetry suggested a weaker dependence on spin state, but in the reverse order of the observed hET reduction rates. Oxidation and reduction rates of cyt P450s in the films are also likely to depend on protein secondary structure around the heme iron.
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Affiliation(s)
- Sadagopan Krishnan
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, USA
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22
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Schulzke C. Temperature dependent electrochemistry--a versatile tool for investigations of biology related topics. Dalton Trans 2009:6683-91. [PMID: 19690674 DOI: 10.1039/b904361f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Temperature dependent electrochemistry can be efficiently used to determine very different properties of the investigated system, such as thermodynamic parameters of redox processes (especially the entropy), the degeneration temperature of a protein or kinetic parameters, for instance activation energy. It can even be used in biotechnology for improved catalysis and detection of substances. This perspective describes a selection of different experiments that used temperature dependent electrochemistry in order to determine these different values or achieve an enhancement of biotechnological applications, respectively, and hence gives an overview of its versatile use in studies aimed at biological issues.
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Affiliation(s)
- Carola Schulzke
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland.
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23
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Hlavica P. Assembly of non-natural electron transfer conduits in the cytochrome P450 system: A critical assessment and update of artificial redox constructs amenable to exploitation in biotechnological areas. Biotechnol Adv 2009; 27:103-21. [DOI: 10.1016/j.biotechadv.2008.10.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Revised: 09/29/2008] [Accepted: 10/04/2008] [Indexed: 10/21/2022]
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24
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Guto PM, Kumar CV, Rusling JF. Thermostable biocatalytic films of enzymes and polylysine on electrodes and nanoparticles in microemulsions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:10365-70. [PMID: 18690734 DOI: 10.1021/la801644e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Microemulsions of oil, water and surfactant were evaluated as media for biocatalysis at high temperatures employing films of polylysine (PLL) and the enzymes horseradish peroxidase (HRP), soybean peroxidase (SBP) and the protein myoglobin (Mb). PLL was covalently linked to oxidized pyrolytic graphite electrodes or carboxylated 500 nm diameter silica nanoparticles, then cross-linked by amidization to HRP, SBP and Mb. The resulting film systems were stable at 90 degrees C for >12 h in microemulsions. Characterization of the microemulsions by conductivity, viscosity and probe diffusion coefficients suggested that these media have bicontinuous microstructures from 25 to 90 degrees C. UV circular dichroism and visible spectroscopy confirmed that the enzymes retained near-native conformation in the films at temperatures as high as 90 degrees C. Oxidation of o-methoxyphenol to 3,3'-dimethoxy-4,4'-biphenoquinone by enzyme-PLL films on silica nanoparticles gave yields 3-5-fold larger in microemulsions at 90 degrees C compared to the same reaction at 25 degrees C. The best yields were in CTAB microemulsions and were 3-fold larger than in buffers at 90 degrees C.
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Affiliation(s)
- Peterson M Guto
- Department of Chemistry, University of Connecticut, Storrs, CT 06269, USA
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25
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Rabe KS, Kiko K, Niemeyer CM. Characterization of the peroxidase activity of CYP119, a thermostable P450 from Sulfolobus acidocaldarius. Chembiochem 2008; 9:420-5. [PMID: 18157853 DOI: 10.1002/cbic.200700450] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We report the cloning, expression, and purification of CYP119, a thermostable enzyme previously thought to derive from Sulfolobus solfataricus. Sequence analysis suggested that, in contrast to the conclusions of earlier studies, the enzyme stems from the closely related Sulfolobus acidocaldarius, and we were indeed able to clone the gene from the genomic DNA of this organism. For the first time, we report here on the peroxidase activity of this enzyme and the optimization of the associated reaction parameters. The optimized reaction conditions were then applied to the biocatalytic epoxidation of styrene. The values obtained for k(cat) (78.2+/-20.6 min(-1)) and K(M) (9.2+/-4.3 mM) indicated an approximately 100-fold increased catalytic activity over previously reported results.
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Affiliation(s)
- Kersten S Rabe
- Technische Universität Dortmund, Fachbereich Chemie, Biologisch-chemische Mikrostrukturtechnik, Dortmund, Germany
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26
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Rabe KS, Gandubert VJ, Spengler M, Erkelenz M, Niemeyer CM. Engineering and assaying of cytochrome P450 biocatalysts. Anal Bioanal Chem 2008; 392:1059-73. [PMID: 18622752 DOI: 10.1007/s00216-008-2248-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2008] [Revised: 06/11/2008] [Accepted: 06/12/2008] [Indexed: 11/29/2022]
Abstract
Cytochrome P450s constitute a highly fascinating superfamily of enzymes which catalyze a broad range of reactions. They are essential for drug metabolism and promise industrial applications in biotechnology and biosensing. The constant search for cytochrome P450 enzymes with enhanced catalytic performances has generated a large body of research. This review will concentrate on two key aspects related to the identification and improvement of cytochrome P450 biocatalysts, namely the engineering and assaying of these enzymes. To this end, recent advances in cytochrome P450 development are reported and commonly used screening methods are surveyed.
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Affiliation(s)
- Kersten S Rabe
- Fakultät für Chemie, Biologisch-Chemische Mikrostrukturtechnik, Technische Universität Dortmund, Otto-Hahn-Strabetae 6, 44227, Dortmund, Germany
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27
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Bhambhani A, Chah S, Hvastkovs EG, Jensen GC, Rusling JF, Zare RN, Kumar CV. Folding control and unfolding free energy of yeast iso-1-cytochrome c bound to layered zirconium phosphate materials monitored by surface plasmon resonance. J Phys Chem B 2008; 112:9201-8. [PMID: 18598069 DOI: 10.1021/jp7121642] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The free energy change (Delta G degrees ) for the unfolding of immobilized yeast iso-1-cytochrome c (Cyt c) at nanoassemblies was measured by surface plasmon resonance (SPR) spectroscopy. Data show that SPR is sensitive to protein conformational changes, and protein solid interface exerts a major influence on bound protein stability. First, Cyt c was self-assembled on the Au film via the single thiol of Cys-102. Then, crystalline sheets of layered alpha-Zr(O(3)POH)(2).H(2)O (alpha-ZrP) or Zr(O(3)PCH(2)CH(2)COOH)(2).xH(2)O (alpha-ZrCEP) were adsorbed to construct alpha-ZrP/Cyt c/Au or alpha-ZrCEP/Cyt c/Au nanoassemblies. The construction of each layer was monitored by SPR, in real time, and the assemblies were further characterized by atomic force microscopy and electrochemical studies. Thermodynamic stability of the protein nanoassembly was assessed by urea-induced unfolding. Surprisingly, unfolding is reversible in all cases studied here. Stability of Cyt c in alpha-ZrP/Cyt c/Au increased by approximately 4.3 kJ/mol when compared to the unfolding free energy of Cyt c/Au assembly. In contrast, the protein stability decreased by approximately 1.5 kJ/mol for alpha-ZrCEP/Cyt c/Au layer. Thus, OH-decorated surfaces stabilized the protein whereas COOH-decorated surfaces destabilized it. These data quantitate the role of specific functional groups of the inorganic layers in controlling bound protein stability.
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Affiliation(s)
- Akhilesh Bhambhani
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA
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28
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Taglieber A, Schulz F, Hollmann F, Rusek M, Reetz MT. Light-driven biocatalytic oxidation and reduction reactions: scope and limitations. Chembiochem 2008; 9:565-72. [PMID: 18288667 DOI: 10.1002/cbic.200700435] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The quest for practical regeneration concepts for nicotinamide-dependent oxidoreductases continues. Recently we proposed the use of visible light to promote the direct reductive regeneration of a flavin-dependent monooxygenase. With this enzyme (PAMO-P3) light-driven enantioselective Baeyer-Villiger oxidations were performed. In spite of the significant reduction in the complexity achieved, catalytic performance of the novel approach did not meet the requirements for an efficient biocatalytic oxygenation system. Driven by this ultimate goal, we further investigated the limiting factors of our particular system. We discovered that oxidative uncoupling of the flavin-regeneration reaction from enzymatic O2-activation accounts for the futile consumption of approximately 95% of the reducing equivalents provided by the sacrificial electron donor, EDTA. Furthermore, it was found that the apparent turnover frequency (TOF) for PAMO-P3 in the present setup is approximately two orders of magnitude lower than in conventional setups that use NADPH as reductant. This finding was traced to sluggish electron transfer kinetics that arose from an impeded interaction between PAMO-P3-bound FAD and the reducing catalyst. The limiting factors and potential approaches for their circumvention are discussed. Furthermore, we broadened the light-driven regeneration approach to the class of flavin-dependent reductases. By using the Old Yellow Enzyme homologue YqjM as a model system, a significantly higher catalytic turnover for the enzyme catalyst was achieved, which we assign to a higher accessibility of the prosthetic group as well as to the absence of oxidative uncoupling.
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Affiliation(s)
- Andreas Taglieber
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim/Ruhr, Germany
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29
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Guto PM, Kumar CV, Rusling JF. Thermostable peroxidase-polylysine films for biocatalysis at 90 degrees C. J Phys Chem B 2007; 111:9125-31. [PMID: 17608411 DOI: 10.1021/jp071525h] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cross-linked films of poly(l-lysine) (PLL) and enzymes covalently linked to surfaces provided remarkable thermostability, enabling biocatalysis at 90 degrees C. Soret spectra, circular dichroism, and voltammetry showed that PLL films containing peroxidases or myoglobin were stable for up to 9 h at 90 degrees C, while the same enzymes in solution denatured completely within 20 min. Biocatalytic reduction of t-BuOOH with enzyme-PLL films, using rotating disk voltammetry, provided Michaelis kcat/Km values. Results showed that horseradish peroxidase (HRP)-PLL is 3-fold more active than soybean peroxidase (SBP)-PLL at 25 degrees C, but SBP-PLL is slightly more active at 90 degrees C. SBP-PLL films had 8-fold larger kcat/Km values at 90 degrees C compared to 25 degrees C. Oxidation of o-methoxyphenol to 3,3'-dimethoxy-4,4'-biphenoquinone by peroxidase-PLL-coated silica colloids gave better yields at 90 degrees C than 25 degrees C, suggesting increasing catalytic efficiency and selectivity at the higher temperature. These biocolloids were reusable with little loss of activity at 90 degrees C.
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Affiliation(s)
- Peterson M Guto
- Department of Chemistry and Institute of Materials Science, 55 North Eagleville Road, University of Connecticut, Storrs, Connecticut 06269, USA
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30
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The electrochemical properties of thermophilic cytochrome P450 CYP119A2 at extremely high temperatures in poly(ethylene oxide). Electrochem commun 2007. [DOI: 10.1016/j.elecom.2006.09.031] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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31
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Udit AK, Hill MG, Gray HB. Electrochemistry of cytochrome P450 BM3 in sodium dodecyl sulfate films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:10854-7. [PMID: 17129070 PMCID: PMC2515932 DOI: 10.1021/la061162x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Direct electrochemistry of the cytochrome P450 BM3 heme domain (BM3) was achieved by confining the protein within sodium dodecyl sulfate (SDS) films on the surface of basal-plane graphite (BPG) electrodes. Cyclic voltammetry revealed the heme FeIII/II redox couple at -330 mV (vs Ag/AgCl, pH 7.4). Up to 10 V/s, the peak current was linear with the scan rate, allowing us to treat the system as surface-confined within this regime. The standard heterogeneous rate constant determined at 10 V/s was estimated to be 10 s-1. Voltammograms obtained for the BM3-SDS-BPG system in the presence of dioxygen exhibited catalytic waves at the onset of FeIII reduction. The altered heme reduction potential of the BM3-SDS-graphite system indicates that SDS is likely bound in the enzyme active-site region. Compared to other P450-surfactant systems, we find redox potentials and electron-transfer rates that differ by approximately 100 mV and >10-fold, respectively, indicating that the nature of the surfactant environment has a significant effect on the observed heme redox properties.
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Affiliation(s)
- Andrew K. Udit
- Department of Chemistry, Occidental College, California Institute of Technology
| | - Michael G. Hill
- Department of Chemistry, Occidental College, California Institute of Technology
| | - Harry B. Gray
- Division of Chemistry and Chemical Engineering, California Institute of Technology
- *Corresponding author
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32
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Gavrilova GV, Moiseeva AA, Beloglazkina EK, Gavrilov AA, Butin KP. Electrochemical study of the sequence of reductive dehalogenation of 2-bromo-5-dibromomethyl-4-dichloromethyl-4-methylcyclohexa-2,5-dien-1-one and its analogs. Russ Chem Bull 2006. [DOI: 10.1007/s11172-006-0463-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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33
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Udit AK, Hagen KD, Goldman PJ, Star A, Gillan JM, Gray HB, Hill MG. Spectroscopy and Electrochemistry of Cytochrome P450 BM3-Surfactant Film Assemblies. J Am Chem Soc 2006; 128:10320-5. [PMID: 16881664 DOI: 10.1021/ja061896w] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report analyses of electrochemical and spectroscopic measurements on cytochrome P450 BM3 (BM3) in didodecyldimethylammonium bromide (DDAB) surfactant films. Electronic absorption spectra of BM3-DDAB films on silica slides reveal the characteristic low-spin FeIII heme absorption maximum at 418 nm. A prominent peak in the absorption spectrum of BM3 FeII-CO in a DDAB dispersion is at 448 nm; in spectra of aged samples, a shoulder at approximately 420 nm is present. Infrared absorption spectra of the BM3 FeII-CO complex in DDAB dispersions feature a time-dependent shift of the carbonyl stretching frequency from 1950 to 2080 cm(-1). Voltammetry of BM3-DDAB films on graphite electrodes gave the following results: FeIII/II E(1/2) at -260 mV (vs SCE), approximately 300 mV positive of the value measured in solution; DeltaS degrees (rc), DeltaS degrees , and DeltaH degrees values for water-ligated BM3 in DDAB are -98 J mol(-1) K(-1), -163 J mol(-1) K(-1), and -47 kJ mol(-1), respectively; values for the imidazole-ligated enzyme are -8 J mol(-1) K(-1), -73 J mol(-1) K(-1), and -21 kJ mol(-1). Taken together, the data suggest that BM3 adopts a compact conformation within DDAB that in turn strengthens hydrogen bonding interactions with the heme axial cysteine, producing a P420-like species with decreased electron density around the metal center.
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Affiliation(s)
- Andrew K Udit
- Department of Chemistry, Occidental College, Los Angeles, California 90041, USA.
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35
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Udit AK, Hill MG, Gray HB. Electrochemical generation of a high-valent state of cytochrome P450. J Inorg Biochem 2006; 100:519-23. [PMID: 16504300 DOI: 10.1016/j.jinorgbio.2006.01.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2006] [Accepted: 01/16/2006] [Indexed: 11/18/2022]
Abstract
Cyclic voltammetry performed at rapid scan rates on cytochrome P450 from Pseudomonas putida (P450CAM) in didodecyldimethylammonium bromide (DDAB) films on graphite electrodes revealed a couple (E) at 830mV (vs Ag/AgCl). E was not significantly observed at scan rates less than 30V/s at room temperature, suggesting that the oxidized species is unstable. The lifetime of E could be prolonged at 4 degrees C, which allowed reversible access to E at scan rates as low as 1V/s. E was found to be sensitive to imidazole in solution and to variations in pH, suggesting that the redox reaction is occurring at the metal center (i.e., Fe(IV/III)). Electrolysis reactions with different P450 substrates revealed that the electrochemically generated high-valent species is able to convert thioanisole to methyl phenyl sulfoxide.
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Affiliation(s)
- Andrew K Udit
- Department of Chemistry, Occidental College, 1600 Campus Road, Los Angeles, CA 91030, USA.
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36
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Hollmann F, Hofstetter K, Schmid A. Non-enzymatic regeneration of nicotinamide and flavin cofactors for monooxygenase catalysis. Trends Biotechnol 2006; 24:163-71. [PMID: 16488494 DOI: 10.1016/j.tibtech.2006.02.003] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2005] [Revised: 10/25/2005] [Accepted: 02/03/2006] [Indexed: 10/25/2022]
Abstract
Biocatalytic oxygenation chemistry is a rapidly evolving field in which monooxygenases are the tools of choice. Monooxygenases catalyze many industrially important synthetic transformations; however, their use in preparative applications is hampered by their intrinsic requirement for reducing equivalents. As a result, non-enzymatic strategies--where the reducing equivalents are introduced directly into the catalytic cycle--are being developed to supersede the well-established enzymatic NAD(P)H regeneration systems currently in use. In this review we summarize and evaluate recent achievements in this area.
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Affiliation(s)
- F Hollmann
- Degussa Care & Surface Specialties, Goldschmidt AG, Goldschmidtstrasse 100, 45127 Essen, Germany
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37
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Abstract
Oxidoreductase enzymes catalyze single- or multi-electron reduction/oxidation reactions of small molecule inorganic or organic substrates, and they are integral to a wide variety of biological processes including respiration, energy production, biosynthesis, metabolism, and detoxification. All redox enzymes require a natural redox partner such as an electron-transfer protein (e.g. cytochrome, ferredoxin, flavoprotein) or a small molecule cosubstrate (e.g. NAD(P)H, dioxygen) to sustain catalysis, in effect to balance the substrate/product redox half-reaction. In principle, the natural electron-transfer partner may be replaced by an electrochemical working electrode. One of the great strengths of this approach is that the rate of catalysis (equivalent to the observed electrochemical current) may be probed as a function of applied potential through linear sweep and cyclic voltammetry, and insight to the overall catalytic mechanism may be gained by a systematic electrochemical study coupled with theoretical analysis. In this review, the various approaches to enzyme electrochemistry will be discussed, including direct and indirect (mediated) experiments, and a brief coverage of the theory relevant to these techniques will be presented. The importance of immobilizing enzymes on the electrode surface will be presented and the variety of ways that this may be done will be reviewed. The importance of chemical modification of the electrode surface in ensuring an environment conducive to a stable and active enzyme capable of functioning natively will be illustrated. Fundamental research into electrochemically driven enzyme catalysis has led to some remarkable practical applications. The glucose oxidase enzyme electrode is a spectacularly successful application of enzyme electrochemistry. Biosensors based on this technology are used worldwide by sufferers of diabetes to provide rapid and accurate analysis of blood glucose concentrations. Other applications of enzyme electrochemistry are in the sensing of macromolecular complexation events such as antigen–antibody binding and DNA hybridization. The review will include a selection of enzymes that have been successfully investigated by electrochemistry and, where appropriate, discuss their development towards practical biotechnological applications.
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Abstract
Heme-thiolate proteins (HTPs) play critical biological roles by catalyzing challenging chemical reactions. The ability of HTPs to selectively oxidize inert substrates under mild conditions has led to much research aimed at the development of useful in vitro oxidation technology. Very complex electron transfer machinery is required to support HTP chemistry, and electrochemical methods provide many of the needed components. The challenge is to find a system that has good electrode-enzyme electronic coupling that, in turn, would drive catalytic turnover at relatively high rates. Several systems reviewed herein have shown promise in experimental work on components that could be part of a molecular machine for the selective oxidation of organic substrates.
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Affiliation(s)
- Andrew K Udit
- Department of Chemistry, Occidental College, Los Angeles, CA 90041, USA
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39
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Nishida CR, Ortiz de Montellano PR. Thermophilic cytochrome P450 enzymes. Biochem Biophys Res Commun 2005; 338:437-45. [PMID: 16139791 DOI: 10.1016/j.bbrc.2005.08.093] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Indexed: 10/25/2022]
Abstract
Thermophilic cytochrome P450 enzymes are of potential interest from structural, mechanistic, and biotechnological points of view. The structures and properties of two such enzymes, CYP119 and CYP175A1, have been investigated and provide the foundation for future work on thermophilic P450 enzymes.
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Affiliation(s)
- Clinton R Nishida
- Department of Pharmaceutical Chemistry, University of California, 600 16th Street, San Francisco, CA 94143-2280, USA
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40
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Udit AK, Hindoyan N, Hill MG, Arnold FH, Gray HB. Protein−Surfactant Film Voltammetry of Wild-Type and Mutant Cytochrome P450 BM3. Inorg Chem 2005; 44:4109-11. [PMID: 15934729 DOI: 10.1021/ic0483747] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We are investigating the redox chemistry of wild-type (WT) and mutant (1-12G) cytochrome P450 BM3. Absorption spectra in solution feature the Fe(III) Soret at 418 nm for WT and a split Soret for 1-12G at 390 and 418 nm. Voltammetry of the proteins within DDAPSS films on the surface of carbon electrodes reveal nearly identical Fe(III/II) potentials (approximately -200 mV vs Ag/AgCl), but significant differences in k degrees , 250 vs 30 s(-)(1), and Fe(III/II)-CO potentials, -140 vs -115 mV, for WT vs 1-12G. Catalytic reduction of dioxygen by the proteins on rotating-disk electrodes was analyzed using Levich and Koutecky-Levich treatments. The data reveal 1-12G n and k(obs) values that are, respectively, 1.7 and 0.07 times those of WT, suggesting that the two proteins differ strikingly in their reactions with dioxygen.
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Affiliation(s)
- Andrew K Udit
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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