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Gibbs C, Fedoretz-Maxwell BP, MacNeil GA, Walsby CJ, Warren JJ. Proximal Methionine Amino Acid Residue Affects the Properties of Redox-Active Tryptophan in an Artificial Model Protein. ACS OMEGA 2023; 8:19798-19806. [PMID: 37305310 PMCID: PMC10249128 DOI: 10.1021/acsomega.3c01589] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 05/11/2023] [Indexed: 06/13/2023]
Abstract
Redox-active amino acid residues are at the heart of biological electron-transfer reactions. They play important roles in natural protein functions and are implicated in disease states (e.g., oxidative-stress-associated disorders). Tryptophan (Trp) is one such redox-active amino acid residue, and it has long been known to serve a functional role in proteins. Broadly speaking, there is still much to learn about the local features that make some Trp redox active and others inactive. Herein, we describe a new protein model system where we investigate how a methionine (Met) residue proximal to a redox-active Trp affects its reactivity and spectroscopy. We use an artificial variant of azurin from Pseudomonas aeruginosa to produce these models. We employ a series of UV-visible spectroscopy, electrochemistry, electron paramagnetic resonance, and density functional theory experiments to demonstrate the effect that placing Met near Trp radicals has in the context of redox proteins. The introduction of Met proximal to Trp lowers its reduction potential by ca. 30 mV and causes clear shifts in the optical spectra of the corresponding radicals. While the effect may be small, it is significant enough to be a way for natural systems to tune Trp reactivity.
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Takematsu K, Williamson HR, Nikolovski P, Kaiser JT, Sheng Y, Pospíšil P, Towrie M, Heyda J, Hollas D, Záliš S, Gray HB, Vlček A, Winkler JR. Two Tryptophans Are Better Than One in Accelerating Electron Flow through a Protein. ACS CENTRAL SCIENCE 2019; 5:192-200. [PMID: 30693338 PMCID: PMC6346393 DOI: 10.1021/acscentsci.8b00882] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Indexed: 06/09/2023]
Abstract
We have constructed and structurally characterized a Pseudomonas aeruginosa azurin mutant Re126WWCuI , where two adjacent tryptophan residues (W124 and W122, indole separation 3.6-4.1 Å) are inserted between the CuI center and a Re photosensitizer coordinated to the imidazole of H126 (ReI(H126)(CO)3(4,7-dimethyl-1,10-phenanthroline)+). CuI oxidation by the photoexcited Re label (*Re) 22.9 Å away proceeds with a ∼70 ns time constant, similar to that of a single-tryptophan mutant (∼40 ns) with a 19.4 Å Re-Cu distance. Time-resolved spectroscopy (luminescence, visible and IR absorption) revealed two rapid reversible electron transfer steps, W124 → *Re (400-475 ps, K 1 ≅ 3.5-4) and W122 → W124•+ (7-9 ns, K 2 ≅ 0.55-0.75), followed by a rate-determining (70-90 ns) CuI oxidation by W122•+ ca. 11 Å away. The photocycle is completed by 120 μs recombination. No photochemical CuI oxidation was observed in Re126FWCuI , whereas in Re126WFCuI , the photocycle is restricted to the ReH126W124 unit and CuI remains isolated. QM/MM/MD simulations of Re126WWCuI indicate that indole solvation changes through the hopping process and W124 → *Re electron transfer is accompanied by water fluctuations that tighten W124 solvation. Our finding that multistep tunneling (hopping) confers a ∼9000-fold advantage over single-step tunneling in the double-tryptophan protein supports the proposal that hole-hopping through tryptophan/tyrosine chains protects enzymes from oxidative damage.
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Affiliation(s)
- Kana Takematsu
- Department
of Chemistry, Bowdoin College, Brunswick, Maine 04011, United States
| | - Heather R Williamson
- Department
of Chemistry, Xavier University of Louisiana, New Orleans, Louisiana 70125, United States
| | - Pavle Nikolovski
- Beckman
Institute, California Institute of Technology, Pasadena, California 91125, United States
| | - Jens T. Kaiser
- Beckman
Institute, California Institute of Technology, Pasadena, California 91125, United States
| | - Yuling Sheng
- Beckman
Institute, California Institute of Technology, Pasadena, California 91125, United States
| | - Petr Pospíšil
- J.
Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-182 23 Prague, Czech Republic
| | - Michael Towrie
- Central
Laser Facility, Research Complex at Harwell, Science and Technology
Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Didcot,
Oxfordshire, OX11 0FA, U.K.
| | - Jan Heyda
- J.
Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-182 23 Prague, Czech Republic
- Department
of Physical Chemistry, University of Chemistry
and Technology, Prague, Technická 5, CZ-166
28 Prague, Czech Republic
| | - Daniel Hollas
- Department
of Physical Chemistry, University of Chemistry
and Technology, Prague, Technická 5, CZ-166
28 Prague, Czech Republic
| | - Stanislav Záliš
- J.
Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-182 23 Prague, Czech Republic
| | - Harry B. Gray
- Beckman
Institute, California Institute of Technology, Pasadena, California 91125, United States
| | - Antonín Vlček
- J.
Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-182 23 Prague, Czech Republic
- School
of Biological and Chemical Sciences, Queen
Mary University of London, Mile End Road, London E1 4NS, United Kingdom
| | - Jay R. Winkler
- Beckman
Institute, California Institute of Technology, Pasadena, California 91125, United States
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Espinoza EM, Larsen-Clinton JM, Krzeszewski M, Darabedian N, Gryko DT, Vullev VI. Bioinspired approach toward molecular electrets: synthetic proteome for materials. PURE APPL CHEM 2017. [DOI: 10.1515/pac-2017-0309] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
AbstractMolecular-level control of charge transfer (CT) is essential for both, organic electronics and solar-energy conversion, as well as for a wide range of biological processes. This article provides an overview of the utility of local electric fields originating from molecular dipoles for directing CT processes. Systems with ordered dipoles, i.e. molecular electrets, are the centerpiece of the discussion. The conceptual evolution from biomimicry to biomimesis, and then to biological inspiration, paves the roads leading from testing the understanding of how natural living systems function to implementing these lessons into optimal paradigms for specific applications. This progression of the evolving structure-function relationships allows for the development of bioinspired electrets composed of non-native aromatic amino acids. A set of such non-native residues that are electron-rich can be viewed as a synthetic proteome for hole-transfer electrets. Detailed considerations of the electronic structure of an individual residue prove of key importance for designating the points for optimal injection of holes (i.e. extraction of electrons) in electret oligomers. This multifaceted bioinspired approach for the design of CT molecular systems provides unexplored paradigms for electronic and energy science and engineering.
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Affiliation(s)
- Eli M. Espinoza
- Department of Chemistry, University of California, Riverside, CA 92521, USA
| | | | - Maciej Krzeszewski
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44-52, 01-224 Warsaw, Poland
| | - Narek Darabedian
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
| | - Daniel T. Gryko
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44-52, 01-224 Warsaw, Poland
| | - Valentine I. Vullev
- Department of Chemistry, University of California, Riverside, CA 92521, USA
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
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Moncada AS, Einschlag FS, Prieto ED, Ruiz GT, Lappin AG, Ferraudi GJ, Wolcan E. Photophysical properties of Re(I)(CO)3(phen) pendants grafted to a poly-4-vinylpyridine backbone. A correlation between photophysical properties and morphological changes of the backbone. J Photochem Photobiol A Chem 2016. [DOI: 10.1016/j.jphotochem.2016.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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5
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Tobin PH, Wilson CJ. Examining Photoinduced Energy Transfer in Pseudomonas aeruginosa Azurin. J Am Chem Soc 2014; 136:1793-802. [DOI: 10.1021/ja412308r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Peter H. Tobin
- Department
of Chemical and Environmental Engineering, ‡Department of Biomedical
Engineering, and §Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8286, United States
| | - Corey J. Wilson
- Department
of Chemical and Environmental Engineering, ‡Department of Biomedical
Engineering, and §Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8286, United States
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6
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Takematsu K, Williamson H, Blanco-Rodríguez AM, Sokolová L, Nikolovski P, Kaiser JT, Towrie M, Clark IP, Vlček A, Winkler JR, Gray HB. Tryptophan-accelerated electron flow across a protein-protein interface. J Am Chem Soc 2013; 135:15515-25. [PMID: 24032375 PMCID: PMC3855362 DOI: 10.1021/ja406830d] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report a new metallolabeled blue copper protein, Re126W122Cu(I) Pseudomonas aeruginosa azurin, which has three redox sites at well-defined distances in the protein fold: Re(I)(CO)3(4,7-dimethyl-1,10-phenanthroline) covalently bound at H126, a Cu center, and an indole side chain W122 situated between the Re and Cu sites (Re-W122(indole) = 13.1 Å, dmp-W122(indole) = 10.0 Å, Re-Cu = 25.6 Å). Near-UV excitation of the Re chromophore leads to prompt Cu(I) oxidation (<50 ns), followed by slow back ET to regenerate Cu(I) and ground-state Re(I) with biexponential kinetics, 220 ns and 6 μs. From spectroscopic measurements of kinetics and relative ET yields at different concentrations, it is likely that the photoinduced ET reactions occur in protein dimers, (Re126W122Cu(I))2 and that the forward ET is accelerated by intermolecular electron hopping through the interfacial tryptophan: *Re//←W122←Cu(I), where // denotes a protein-protein interface. Solution mass spectrometry confirms a broad oligomer distribution with prevalent monomers and dimers, and the crystal structure of the Cu(II) form shows two Re126W122Cu(II) molecules oriented such that redox cofactors Re(dmp) and W122-indole on different protein molecules are located at the interface at much shorter intermolecular distances (Re-W122(indole) = 6.9 Å, dmp-W122(indole) = 3.5 Å, and Re-Cu = 14.0 Å) than within single protein folds. Whereas forward ET is accelerated by hopping through W122, BET is retarded by a space jump at the interface that lacks specific interactions or water molecules. These findings on interfacial electron hopping in (Re126W122Cu(I))2 shed new light on optimal redox-unit placements required for functional long-range charge separation in protein complexes.
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Affiliation(s)
- Kana Takematsu
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Heather Williamson
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Ana María Blanco-Rodríguez
- Queen Mary University of London, School of Biological and Chemical Sciences, Mile End Road, London E1 4NS, United Kingdom
| | - Lucie Sokolová
- Institute of Physical and Theoretical Chemistry, Goethe-Universität, Max-von-Laue-Str. 7, 60438 Frankfurt am Main, Germany
| | - Pavle Nikolovski
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Jens T. Kaiser
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Michael Towrie
- Central Laser Facility, Research Complex at Harwell, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire, OX11 0FA, UK
| | - Ian P. Clark
- Central Laser Facility, Research Complex at Harwell, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire, OX11 0FA, UK
| | - Antonín Vlček
- Queen Mary University of London, School of Biological and Chemical Sciences, Mile End Road, London E1 4NS, United Kingdom
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-182 23 Prague, Czech Republic
| | - Jay R. Winkler
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Harry B. Gray
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA
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7
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Warren JJ, Winkler JR, Gray HB. Redox properties of tyrosine and related molecules. FEBS Lett 2012; 586:596-602. [PMID: 22210190 PMCID: PMC3298607 DOI: 10.1016/j.febslet.2011.12.014] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Revised: 12/04/2011] [Accepted: 12/12/2011] [Indexed: 11/25/2022]
Abstract
Redox reactions of tyrosine play key roles in many biological processes, including water oxidation and DNA synthesis. We first review the redox properties of tyrosine (and other phenols) in small molecules and related polypeptides, then report work on (H20)/(Y48)-modified Pseudomonas aeruginosa azurin. The crystal structure of this protein (1.18Å resolution) shows that H20 is strongly hydrogen bonded to Y48 (2.7-2.8Å tyrosine-O to histidine-N distance). A firm conclusion is that proper tuning of the tyrosine potential by a proton-accepting base is critical for biological redox functions.
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Affiliation(s)
- Jeffrey J. Warren
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125
| | - Jay R. Winkler
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125
| | - Harry B. Gray
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125
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8
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Lo KKW, Choi AWT, Law WHT. Applications of luminescent inorganic and organometallic transition metal complexes as biomolecular and cellular probes. Dalton Trans 2012; 41:6021-47. [DOI: 10.1039/c2dt11892k] [Citation(s) in RCA: 321] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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9
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Sokolová L, Williamson H, Sýkora J, Hof M, Gray HB, Brutschy B, Vlcek A. Mass spectrometric characterization of oligomers in Pseudomonas aeruginosa azurin solutions. J Phys Chem B 2011; 115:4790-800. [PMID: 21452827 DOI: 10.1021/jp110460k] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have employed laser-induced liquid bead ion desorption mass spectroscopy (LILBID MS) to study the solution behavior of Pseudomonas aeruginosa azurin as well as two mutants and corresponding Re-labeled derivatives containing a Re(CO)(3)(4,7-dimethyl-1,10-phenanthroline)(+) chromophore appended to a surface histidine. LILBID spectra show broad oligomer distributions whose particular patterns depend on the solution composition (pure H(2)O, 20-30 mM NaCl, 20 and 50 mM NaP(i) or NH(4)P(i) at pH = 7). The distribution maximum shifts to smaller oligomers upon decreasing the azurin concentration and increasing the buffer concentration. Oligomerization is less extensive for native azurin than its mutants. The oligomerization propensities of unlabeled and Re-labeled proteins are generally comparable, and only Re126 shows some preference for the dimer that persists even in highly diluted solutions. Peak shifts to higher masses and broadening in 20-50 mM NaP(i) confirm strong azurin association with buffer ions and solvation. We have found that LILBID MS reveals the solution behavior of weakly bound nonspecific protein oligomers, clearly distinguishing individual components of the oligomer distribution. Independently, average data on oligomerization and the dependence on solution composition were obtained by time-resolved anisotropy of the Re-label photoluminescence that confirmed relatively long rotation correlation times, 6-30 ns, depending on Re-azurin and solution composition. Labeling proteins with Re-chromophores that have long-lived phosphorescence extends the time scale of anisotropy measurements to hundreds of nanoseconds, thereby opening the way for investigations of large oligomers with long rotation times.
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Affiliation(s)
- Lucie Sokolová
- Institute of Physical and Theoretical Chemistry, Goethe University, Frankfurt am Main, Germany
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10
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Eckermann AL, Feld DJ, Shaw JA, Meade TJ. Electrochemistry of redox-active self-assembled monolayers. Coord Chem Rev 2010; 254:1769-1802. [PMID: 20563297 PMCID: PMC2885823 DOI: 10.1016/j.ccr.2009.12.023] [Citation(s) in RCA: 357] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Redox-active self-assembled monolayers (SAMs) provide an excellent platform for investigating electron transfer kinetics. Using a well-defined bridge, a redox center can be positioned at a fixed distance from the electrode and electron transfer kinetics probed using a variety of electrochemical techniques. Cyclic voltammetry, AC voltammetry, electrochemical impedance spectroscopy, and chronoamperometry are most commonly used to determine the rate of electron transfer of redox-activated SAMs. A variety of redox species have been attached to SAMs, and include transition metal complexes (e.g., ferrocene, ruthenium pentaammine, osmium bisbipyridine, metal clusters) and organic molecules (e.g., galvinol, C(60)). SAMs offer an ideal environment to study the outer-sphere interactions of redox species. The composition and integrity of the monolayer and the electrode material influence the electron transfer kinetics and can be investigated using electrochemical methods. Theoretical models have been developed for investigating SAM structure. This review discusses methods and monolayer compositions for electrochemical measurements of redox-active SAMs.
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11
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Lo KKW. Exploitation of Luminescent Organometallic Rhenium(I) and Iridium(III) Complexes in Biological Studies. TOP ORGANOMETAL CHEM 2010. [DOI: 10.1007/3418_2009_3] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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12
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Blanco-Rodríguez AM, Busby M, Ronayne K, Towrie M, Grădinaru C, Sudhamsu J, Sýkora J, Hof M, Záliš S, Di Bilio AJ, Crane BR, Gray HB, Vlček A. Relaxation Dynamics of Pseudomonas aeruginosa ReI(CO)3(α-diimine)(HisX)+ (X = 83, 107, 109, 124, 126)CuII Azurins. J Am Chem Soc 2009; 131:11788-800. [DOI: 10.1021/ja902744s] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ana María Blanco-Rodríguez
- School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom, Central Laser Facility, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, United Kingdom, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Prague, Czech Republic, and Beckman Institute, California Institute
| | - Michael Busby
- School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom, Central Laser Facility, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, United Kingdom, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Prague, Czech Republic, and Beckman Institute, California Institute
| | - Kate Ronayne
- School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom, Central Laser Facility, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, United Kingdom, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Prague, Czech Republic, and Beckman Institute, California Institute
| | - Michael Towrie
- School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom, Central Laser Facility, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, United Kingdom, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Prague, Czech Republic, and Beckman Institute, California Institute
| | - Cristian Grădinaru
- School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom, Central Laser Facility, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, United Kingdom, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Prague, Czech Republic, and Beckman Institute, California Institute
| | - Jawahar Sudhamsu
- School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom, Central Laser Facility, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, United Kingdom, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Prague, Czech Republic, and Beckman Institute, California Institute
| | - Jan Sýkora
- School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom, Central Laser Facility, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, United Kingdom, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Prague, Czech Republic, and Beckman Institute, California Institute
| | - Martin Hof
- School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom, Central Laser Facility, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, United Kingdom, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Prague, Czech Republic, and Beckman Institute, California Institute
| | - Stanislav Záliš
- School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom, Central Laser Facility, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, United Kingdom, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Prague, Czech Republic, and Beckman Institute, California Institute
| | - Angel J. Di Bilio
- School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom, Central Laser Facility, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, United Kingdom, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Prague, Czech Republic, and Beckman Institute, California Institute
| | - Brian R. Crane
- School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom, Central Laser Facility, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, United Kingdom, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Prague, Czech Republic, and Beckman Institute, California Institute
| | - Harry B. Gray
- School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom, Central Laser Facility, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, United Kingdom, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Prague, Czech Republic, and Beckman Institute, California Institute
| | - Antonín Vlček
- School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom, Central Laser Facility, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, United Kingdom, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Prague, Czech Republic, and Beckman Institute, California Institute
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13
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Shafaat HS, Leigh BS, Tauber MJ, Kim JE. Resonance Raman Characterization of a Stable Tryptophan Radical in an Azurin Mutant. J Phys Chem B 2008; 113:382-8. [PMID: 19072535 DOI: 10.1021/jp809329a] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Hannah S. Shafaat
- Department of Chemistry & Biochemistry, University of California at San Diego, La Jolla, California 92093
| | - Brian S. Leigh
- Department of Chemistry & Biochemistry, University of California at San Diego, La Jolla, California 92093
| | - Michael J. Tauber
- Department of Chemistry & Biochemistry, University of California at San Diego, La Jolla, California 92093
| | - Judy E. Kim
- Department of Chemistry & Biochemistry, University of California at San Diego, La Jolla, California 92093
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14
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Conlan B. Designing photosystem II: molecular engineering of photo-catalytic proteins. PHOTOSYNTHESIS RESEARCH 2008; 98:687-700. [PMID: 18777102 DOI: 10.1007/s11120-008-9355-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Accepted: 08/11/2008] [Indexed: 05/26/2023]
Abstract
Biological photosynthesis utilizes membrane-bound pigment/protein complexes to convert light into chemical energy through a series of electron-transfer events. In the unique photosystem II (PSII) complex these electron-transfer events result in the oxidation of water to molecular oxygen. PSII is an extremely complex enzyme and in order to exploit its unique ability to convert sunlight into chemical energy it will be necessary to make a minimal model. Here we will briefly describe how PSII functions and identify those aspects that are essential in order to catalyze the oxidation of water into O(2), and review previous attempts to design simple photo-catalytic proteins and summarize our current research exploiting the E. coli bacterioferritin protein as a scaffold into which multiple cofactors can be bound, to oxidize a manganese metal center upon illumination. Through the reverse engineering of PSII and light driven water splitting reactions it may be possible to provide a blueprint for catalysts that can produce clean green fuel for human energy needs.
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Affiliation(s)
- Brendon Conlan
- Research School of Biological Science, Australian National University, Canberra, ACT 0200, Australia.
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Machczynski MC, Kuhl KP, McGuirl MA. Modulation of the electrochemical behavior of tyrosyl radicals by the electrode surface. Anal Biochem 2007; 362:89-97. [PMID: 17254538 DOI: 10.1016/j.ab.2006.11.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2006] [Revised: 11/22/2006] [Accepted: 11/30/2006] [Indexed: 11/20/2022]
Abstract
The ability to adsorb proteins and enzymes on electrode surfaces enhances opportunities for studying enzyme activity and redox-based catalysis. Proteins may be bound in a chosen orientation on surfaces so that specific sites within them may be preferentially studied, but to date no systematic study of a redox moiety from solvent to electrode surface to the protein milieu has been performed. We report the redox and ionization behavior of tyrosine-cysteine, using the cysteine residue to form covalent linkages with Au and self-assembled-monolayer (SAM)-modified Au surfaces and using the tyrosine for redox activity. In addition, the same redox fragment incorporated into a protein bound to a SAM is examined. We find that directly binding the dipeptide to Au causes the greatest change in properties, while binding it to the SAM causes a slight perturbation in redox potential and a significant perturbation in pK(a). When azurin with a surface-exposed tyrosine is bound to a SAM-modified electrode, the redox potential and pK(a) of the tyrosine are nearly unperturbed from the values found for the dipeptide free in solution. Finally, quantification of the voltammetric signal indicates that tyrosine oxidation in the protein triggers the additional oxidation of another nearby amino acid.
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Affiliation(s)
- Michael C Machczynski
- Division of Biological Sciences and Biomolecular Structure and Dynamics Program, The University of Montana, Missoula, MT 59812, USA
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16
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Haquette P, Salmain M, Svedlung K, Martel A, Rudolf B, Zakrzewski J, Cordier S, Roisnel T, Fosse C, Jaouen G. Cysteine-Specific, Covalent Anchoring of Transition Organometallic Complexes to the Protein Papain fromCarica papaya. Chembiochem 2007; 8:224-31. [PMID: 17167808 DOI: 10.1002/cbic.200600387] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Site-directed and covalent introduction of various transition metal-organic entities to the active site of the cysteine endoproteinase, papain, was achieved by treatment of this enzyme with a series of organometallic maleimide derivatives specially designed for the purpose. Kinetic studies made it clear that time-dependent irreversible inactivation of papain occurred in the presence of these organometallic maleimides as a result of Michael addition of the sulfhydryl of Cys25. The rate and mechanism of inactivation were highly dependent on the structure of the organometallic entity attached to the maleimide group. Combined ESI-MS and IR analysis indicated that all the resulting papain adducts contained one organometallic moiety per protein molecule. This confirmed that chemospecific introduction of the metal complexes was indeed achieved. Thus, three novel reagents for heavy-atom derivatization of protein crystals, which include ruthenium, rhenium and tungsten, are now available for the introduction of electron-dense scatterers for phasing of X-ray crystallographic data.
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Affiliation(s)
- Pierre Haquette
- Ecole Nationale Supérieure de Chimie de Paris, Laboratoire de Chimie et Biochimie des Complexes Moléculaires (UMR CNRS 7576), 75231 Paris Cedex 05, France
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17
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Reece SY, Seyedsayamdost MR, Stubbe J, Nocera DG. Electron Transfer Reactions of Fluorotyrosyl Radicals. J Am Chem Soc 2006; 128:13654-5. [PMID: 17044670 DOI: 10.1021/ja0636688] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The complex Re(bpy)(CO)3CN is an excited state oxidant of tyrosine upon deprotonation of the tyrosyl phenol. A series of Re(bpy-FnY)(CO)3CN complexes ([Re]-FnY: [Re]-Y, [Re]-3-FY, [Re]-3,5-F2Y, [Re]-2,3-F2Y, [Re]-2,3,5-F3Y, [Re]-2,3,6-F3Y, and [Re]-F4Y) have been prepared so as to vary the FnY*/FnY- reduction potential and thus the driving force for electron transfer in this system. Time-resolved emission and nanosecond absorption spectroscopies have been used to measure the rates for charge separation, CS, and charge recombination, CR, for each complex. A driving force analysis reveals that CS is well described by Marcus' theory for ET, is strongly driving force dependent (activated), and occurs in the normal region for ET. CR, on the other hand, is weakly driving force dependent (near activationless) and occurs in the inverted region for ET. These data demonstrate that fluorotyrosines will be powerful probes for unraveling charge transport mechanisms in enzymes that utilize tyrosyl radicals.
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Affiliation(s)
- Steven Y Reece
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139-4307, USA
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18
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Blanco-Rodríguez AM, Busby M, Gradinaru C, Crane BR, Di Bilio AJ, Matousek P, Towrie M, Leigh BS, Richards JH, Vlcek A, Gray HB. Excited-State Dynamics of Structurally Characterized [Re
I
(CO)
3
(phen)(HisX)]
+
(X = 83, 109)
Pseudomonas a
eruginosa
Azurins in Aqueous Solution. J Am Chem Soc 2006; 128:4365-70. [PMID: 16569013 DOI: 10.1021/ja057451+] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The triplet metal-to-ligand charge transfer ((3)MLCT) dynamics of two structurally characterized Re(I)(CO)(3)(phen)(HisX)-modified (phen = 1,10-phenanthroline; X = 83, 109) Pseudomonas aeruginosa azurins have been investigated by picosecond time-resolved infrared (TRIR) spectroscopy in aqueous (D(2)O) solution. The (3)MLCT relaxation dynamics exhibited by the two Re(I)-azurins are very different from those of the sensitizer [Re(I)(CO)(3)(phen)(im)](+) (im = imidazole). Whereas the Re(I)(CO)(3) intramolecular vibrational relaxation in Re(I)(CO)(3)(phen)(HisX)Az (4 ps) is similar to that of [Re(I)(CO)(3)(phen)(im)](+) (2 ps), the medium relaxation is much slower ( approximately 250 vs 9.5 ps); the 250-ps relaxation is attributable to reorientation of D(2)O molecules as well as structural reorganization of the rhenium chromophore and nearby polar amino acids in each of the modified proteins.
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19
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Lo KKW. Luminescent Transition Metal Complexes as Biological Labels and Probes. PHOTOFUNCTIONAL TRANSITION METAL COMPLEXES 2006. [DOI: 10.1007/430_2006_040] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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20
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Reece SY, Nocera DG. Direct Tyrosine Oxidation Using the MLCT Excited States of Rhenium Polypyridyl Complexes. J Am Chem Soc 2005; 127:9448-58. [PMID: 15984872 DOI: 10.1021/ja0510360] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Rhenium(I) polypyridyl complexes have been designed for the intramolecular photogeneration of tyrosyl radical. Tyrosine (Y) and phenylalanine (F) have each been separately appended to a conventional Re(I)(bpy)(CO)(3)CN framework via an amide linkage to the bipyridine (bpy) ligand. Comparative time-resolved emission quenching and transient absorption spectra of Re(bpy-Y)(CO)(3)CN and Re(bpy-F)(CO)(3)CN show that Y is oxidized only upon its deprotonation at pH 12. In an effort to redirect electron transport so that it is more compatible with intramolecular Y oxidation, polypyridyl Re(I) complexes have been prepared with the amide bond functionality located on a pendant phosphine ligand. A [Re(phen)(PP-Bn)(CO)(2)](PF(6)) (PP = bis(diphenylphosphino)ethylene) complex has been synthesized and crystallographically characterized. Electrochemistry and phosphorescence measurements of this complex indicate a modest excited-state potential for tyrosine oxidation, similar to that for the (bpy)Re(I)(CO)(3)CN framework. The excited-state oxidation potential can be increased by introducing a monodentate phosphine to the Re(I)(NN)(CO)(3)(+) framework (NN = polypyridyl). In this case, Y is oxidized at all pHs when appended to the triphenylphosphine (P) of [Re(phen)(P-Y)(CO(3))](PF(6)). Analysis of the pH dependence of the rate constant for tyrosyl radical generation is consistent with a proton-coupled electron transfer (PCET) quenching mechanism.
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Affiliation(s)
- Steven Y Reece
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139-4307, USA
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21
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Skourtis SS, Balabin IA, Kawatsu T, Beratan DN. Protein dynamics and electron transfer: electronic decoherence and non-Condon effects. Proc Natl Acad Sci U S A 2005; 102:3552-7. [PMID: 15738409 PMCID: PMC553344 DOI: 10.1073/pnas.0409047102] [Citation(s) in RCA: 155] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We compute the autocorrelation function of the donor-acceptor tunneling matrix element <T(DA)(t)T(DA)(0)> for six Ru-azurin derivatives. Comparison of this decay time to the decay time of the time-dependent Franck-Condon factor {computed by Rossky and coworkers [Lockwood, D. M., Cheng, Y.-K. & Rossky, P. J. (2001) Chem. Phys. Lett. 345, 159-165]} reveals the extent to which non-Condon effects influence the electron-transfer rate. <T(DA)(t)T(DA)(0)> is studied as a function of donor-acceptor distance, tunneling pathway structure, tunneling energy, and temperature to explore the structural and dynamical origins of non-Condon effects. For azurin, the correlation function is remarkably insensitive to tunneling pathway structure. The decay time is only slightly shorter than it is for solvent-mediated electron transfer in small organic molecules and originates, largely, from fluctuations of valence angles rather than bond lengths.
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Affiliation(s)
- Spiros S Skourtis
- Department of Physics, University of Cyprus, P.O. Box 20537, Nicosia 1678, Cyprus.
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