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Golden E, Karton A, Vrielink A. High-resolution structures of cholesterol oxidase in the reduced state provide insights into redox stabilization. ACTA ACUST UNITED AC 2014; 70:3155-66. [PMID: 25478834 DOI: 10.1107/s139900471402286x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 10/17/2014] [Indexed: 01/09/2023]
Abstract
Cholesterol oxidase (CO) is a flavoenzyme that catalyzes the oxidation and isomerization of cholesterol to cholest-4-en-3-one. The reductive half reaction occurs via a hydride transfer from the substrate to the FAD cofactor. The structures of CO reduced with dithionite under aerobic conditions and in the presence of the substrate 2-propanol under both aerobic and anaerobic conditions are presented. The 1.32 Å resolution structure of the dithionite-reduced enzyme reveals a sulfite molecule covalently bound to the FAD cofactor. The isoalloxazine ring system displays a bent structure relative to that of the oxidized enzyme, and alternate conformations of a triad of aromatic residues near to the cofactor are evident. A 1.12 Å resolution anaerobically trapped reduced enzyme structure in the presence of 2-propanol does not show a similar bending of the flavin ring system, but does show alternate conformations of the aromatic triad. Additionally, a significant difference electron-density peak is observed within a covalent-bond distance of N5 of the flavin moiety, suggesting that a hydride-transfer event has occurred as a result of substrate oxidation trapping the flavin in the electron-rich reduced state. The hydride transfer generates a tetrahedral geometry about the flavin N5 atom. High-level density-functional theory calculations were performed to correlate the crystallographic findings with the energetics of this unusual arrangement of the flavin moiety. These calculations suggest that strong hydrogen-bond interactions between Gly120 and the flavin N5 centre may play an important role in these structural features.
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Affiliation(s)
- Emily Golden
- School of Chemistry and Biochemistry, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Amir Karton
- School of Chemistry and Biochemistry, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Alice Vrielink
- School of Chemistry and Biochemistry, University of Western Australia, Crawley, Western Australia 6009, Australia
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2
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Synthesis, characterization and theoretical studies of ruthenium(II) complexes with the quinone functionalized polypyridine ligand, Nqphen. Polyhedron 2012. [DOI: 10.1016/j.poly.2012.03.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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3
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Design of bis(acylamino)triazine containing ruthenium–acetylides as self-complementary supramolecular units. J Organomet Chem 2011. [DOI: 10.1016/j.jorganchem.2010.09.047] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Lechner R, Kümmel S, König B. Visible light flavin photo-oxidation of methylbenzenes, styrenes and phenylacetic acids. Photochem Photobiol Sci 2010; 9:1367-77. [DOI: 10.1039/c0pp00202j] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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6
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Caldwell ST, Farrugia LJ, Hewage SG, Kryvokhyzha N, Rotello VM, Cooke G. Model systems for flavoenzyme activity: an investigation of the role functionality attached to the C(7) position of the flavin unit has on redox and molecular recognition properties. Chem Commun (Camb) 2009:1350-2. [PMID: 19259584 DOI: 10.1039/b900269n] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We describe the role functionality attached to the C(7) position of a family of flavin derivatives has in tuning their redox and recognition properties and the subsequent exploitation of two of these derivatives as a three-component electrochemically controllable molecular switch.
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Affiliation(s)
- Stuart T Caldwell
- Glasgow Centre for Physical Organic Chemistry, WestCHEM, Department of Chemistry, Joseph Black Building, University of Glasgow, Glasgow, UK G12 8QQ
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7
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Abstract
Redox-active enzymes perform many key biological reactions. The electron transfer process is complex, not only because of its versatility, but also because of the intricate and delicate modulation exerted by the protein scaffold on the redox properties of the catalytic sites. Nowadays, there is a wealth of information available about the catalytic mechanisms of redox-active enzymes and the time is propitious for the development of projects based on the protein engineering of redox-active enzymes. In this review, we aim to provide an updated account of the available methods used for protein engineering, including both genetic and chemical tools, which are usually reviewed separately. Specific applications to redox-active enzymes are mentioned within each technology, with emphasis on those cases where the generation of novel functionality was pursued. Finally, we focus on two emerging fields in the protein engineering of redox-active enzymes: the construction of novel nucleic acid-based catalysts and the remodeling of intra-molecular electron transfer networks. We consider that the future development of these areas will represent fine examples of the concurrence of chemical and genetic tools.
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Affiliation(s)
- Gloria Saab-Rincón
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
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8
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Schmaderer H, Hilgers P, Lechner R, König B. Photooxidation of Benzyl Alcohols with Immobilized Flavins. Adv Synth Catal 2009. [DOI: 10.1002/adsc.200800576] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Agasti SS, Caldwell ST, Cooke G, Jordan BJ, Kennedy A, Kryvokhyzha N, Rabani G, Rana S, Sanyal A, Rotello VM. Dendron-based model systems for flavoenzyme activity: towards a new class of synthetic flavoenzyme. Chem Commun (Camb) 2008:4123-5. [PMID: 18802503 DOI: 10.1039/b809568j] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Three generations of water-soluble flavin dendrons have been synthesized and the role dendrimer generation has on the physical and catalytic properties of these assemblies has been investigated.
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Affiliation(s)
- Sarit S Agasti
- Department of Chemistry, University of Massachusetts at Amherst, Amherst, MA 01003, USA
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11
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Svoboda J, Schmaderer H, König B. Thiourea-Enhanced Flavin Photooxidation of Benzyl Alcohol. Chemistry 2008; 14:1854-65. [DOI: 10.1002/chem.200701319] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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12
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Caldwell ST, Cooke G, Hewage SG, Mabruk S, Rabani G, Rotello V, Smith BO, Subramani C, Woisel P. Model systems for flavoenzyme activity: intramolecular self-assembly of a flavin derivative via hydrogen bonding and aromatic interactions. Chem Commun (Camb) 2008:4126-8. [DOI: 10.1039/b809762c] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Jordan BJ, Cooke G, Garety JF, Pollier MA, Kryvokhyzha N, Bayir A, Rabani G, Rotello VM. Polymeric model systems for flavoenzyme activity: towards synthetic flavoenzymes. Chem Commun (Camb) 2007:1248-50. [PMID: 17356772 DOI: 10.1039/b616159f] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report the synthesis of a water-soluble flavin polymer using ATRP, whereby the oligoethylene glycol backbone provides both a local hydrophobic environment and redox tuning of the flavin moiety typical of flavoenzyme prototypes.
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Affiliation(s)
- Brian J Jordan
- Department of Chemistry, University of Massachusetts at Amherst, Amherst, MA 01003, USA
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Boyd ASF, Carroll JB, Cooke G, Garety JF, Jordan BJ, Mabruk S, Rosair G, Rotello VM. Model systems for flavoenzyme activity: a tuneable intramolecularly hydrogen bonded flavin-diamidopyridine complex. Chem Commun (Camb) 2005:2468-70. [PMID: 15886773 DOI: 10.1039/b501887k] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report the electrochemically tuneable intramolecular hydrogen bonding interactions between a covalently linked flavin-diamidopyridine unit.
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Affiliation(s)
- Alan S F Boyd
- Centre for Biomimetic Design & Synthesis, Chemistry, William H. Perkin Building, School of Engineering & Physical Sciences, Heriot-Watt University, Riccarton, Edinburgh, UK
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15
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Reichenbach-Klinke R, Kruppa M, König B. NADH model systems functionalized with Zn(II)-cyclen as flavin binding site-structure dependence of the redox reaction within reversible aggregates. J Am Chem Soc 2002; 124:12999-3007. [PMID: 12405826 DOI: 10.1021/ja026719j] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The relative positions and conformations of the prosthetic group FAD and the cofactor NADH have been remarkably conserved within the structurally diverse group of flavin enzymes. To provide a chemical rational for such an obviously optimal relative disposition of the redox partners for efficient reaction we have synthesized NADH models with Zn(II)-cyclen substituents for reversible flavin binding in water. Altogether, four of these model systems with systematically varying spacer length between the recognition site and the redox active dihydronicotinamide were prepared. The binding of these model systems to riboflavin tetraacetate was confirmed by potentiometric pH titration in water and their reaction with flavin was followed by UV-vis spectroscopy in aqueous media under physiological conditions. The measurements reveal a significant rate enhancement of up to 175 times that of an intermolecular reaction. Moreover, a strong dependence of the reaction rate on the spacer length was observed, which clearly shows that within the dynamic reversible assembly only the optimal relative disposition of the redox partners ensures an efficient redox reaction.
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Fiammengo R, Crego-Calama M, Reinhoudt DN. Synthetic self-assembled models with biomimetic functions. Curr Opin Chem Biol 2001; 5:660-73. [PMID: 11738176 DOI: 10.1016/s1367-5931(01)00263-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Self-assembly can be considered a powerful tool in the hand of chemists for the understanding, modeling and mimicking of biological systems. The possibility of reproducing biological functions in synthetic systems obtained by self-assembly is envisioned as a modest but very important step towards the understanding of the mystery of life and its emergence on Earth.
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Affiliation(s)
- R Fiammengo
- Laboratory of Supramolecular Chemistry and Technology, MESA+ Research Institute, University of Twente, PO Box 217, 7500 AE, Enschede, The Netherlands
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Goodman AJ, Breinlinger EC, McIntosh CM, Grimaldi LN, Rotello VM. Model systems for flavoenzyme activity. Control of flavin recognition via specific electrostatic interactions. Org Lett 2001; 3:1531-4. [PMID: 11388859 DOI: 10.1021/ol015838l] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[structure: see text] A model system has been used to study the interactions of dipole-containing aromatic systems with oxidized and reduced flavin. Ab initio computational and experimental studies show that dipole orientation within the host is a critical determinant for recognition and redox behavior of the flavin guest.
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Affiliation(s)
- A J Goodman
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, USA
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18
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Schwögler A, Carell T. Toward catalytically active oligonucleotides: synthesis of a flavin nucleotide and its incorporation into DNA. Org Lett 2000; 2:1415-8. [PMID: 10814461 DOI: 10.1021/ol005739s] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction--see text] The synthesis of a vitamin B(2)-derived flavin-nucleotide is described. A combined H-phosphonate/phosphoramidite protocol was developed for the first incorporation of flavin coenzymes into a DNA stack. The coenzyme-DNA is predicted to have novel biosensing and catalytic properties.
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Affiliation(s)
- A Schwögler
- Department of Chemistry, Philipps-University Marburg, Germany
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