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Kimura H, Nagasato N, Kato N, Kojima M, Enomoto C, Nakata E, Takashima H. Photophysical and elecron-transfer reaction properties of tris(2,2’-bipyridine)ruthenium(II)-based inhibitors that covalently bound to the active site of chymotrypsin. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY 2021. [DOI: 10.1016/j.jpap.2021.100027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Takematsu K, Pospíšil P, Pižl M, Towrie M, Heyda J, Záliš S, Kaiser JT, Winkler JR, Gray HB, Vlček A. Hole Hopping Across a Protein-Protein Interface. J Phys Chem B 2019; 123:1578-1591. [PMID: 30673250 PMCID: PMC6384139 DOI: 10.1021/acs.jpcb.8b11982] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have investigated photoinduced hole hopping in a Pseudomonas aeruginosa azurin mutant Re126WWCuI, where two adjacent tryptophan residues (W124 and W122) are inserted between the CuI center and a Re photosensitizer coordinated to a H126 imidazole (Re = ReI(H126)(CO)3(dmp)+, dmp = 4,7-dimethyl-1,10-phenanthroline). Optical excitation of this mutant in aqueous media (≤40 μM) triggers 70 ns electron transport over 23 Å, yielding a long-lived (120 μs) ReI(H126)(CO)3(dmp•-)WWCuII product. The Re126FWCuI mutant (F124, W122) is not redox-active under these conditions. Upon increasing the concentration to 0.2-2 mM, {Re126WWCuI}2 and {Re126FWCuI}2 are formed with the dmp ligand of the Re photooxidant of one molecule in close contact (3.8 Å) with the W122' indole on the neighboring chain. In addition, {Re126WWCuI}2 contains an interfacial tryptophan quadruplex of four indoles (3.3-3.7 Å apart). In both mutants, dimerization opens an intermolecular W122' → //*Re ET channel (// denotes the protein interface, *Re is the optically excited sensitizer). Excited-state relaxation and ET occur together in two steps (time constants of ∼600 ps and ∼8 ns) that lead to a charge-separated state containing a Re(H126)(CO)3(dmp•-)//(W122•+)' unit; then (CuI)' is oxidized intramolecularly (60-90 ns) by (W122•+)', forming ReI(H126)(CO)3(dmp•-)WWCuI//(CuII)'. The photocycle is closed by ∼1.6 μs ReI(H126)(CO)3(dmp•-) → //(CuII)' back ET that occurs over 12 Å, in contrast to the 23 Å, 120 μs step in Re126WWCuI. Importantly, dimerization makes Re126FWCuI photoreactive and, as in the case of {Re126WWCuI}2, channels the photoproduced "hole" to the molecule that was not initially photoexcited, thereby shortening the lifetime of ReI(H126)(CO)3(dmp•-)//CuII. Although two adjacent W124 and W122 indoles dramatically enhance CuI → *Re intramolecular multistep ET, the tryptophan quadruplex in {Re126WWCuI}2 does not accelerate intermolecular electron transport; instead, it acts as a hole storage and crossover unit between inter- and intramolecular ET pathways. Irradiation of {Re126WWCuII}2 or {Re126FWCuII}2 also triggers intermolecular W122' → //*Re ET, and the Re(H126)(CO)3(dmp•-)//(W122•+)' charge-separated state decays to the ground state by ∼50 ns ReI(H126)(CO)3(dmp•-)+ → //(W122•+)' intermolecular charge recombination. Our findings shed light on the factors that control interfacial hole/electron hopping in protein complexes and on the role of aromatic amino acids in accelerating long-range electron transport.
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Affiliation(s)
- Kana Takematsu
- Department of Chemistry, Bowdoin College, Brunswick, ME 04011, USA
| | - Petr Pospíšil
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-182 23 Prague, Czech Republic
| | - Martin Pižl
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-182 23 Prague, Czech Republic
- University of Chemistry and Technology, Prague, Technická 5, CZ-166 28 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, UK
| | - Jan Heyda
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-182 23 Prague, Czech Republic
- 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
| | - Jens T. Kaiser
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - 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
| | - Antonín Vlček
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-182 23 Prague, Czech Republic
- Queen Mary University of London, School of Biological and Chemical Sciences, Mile End Road, London E1 4NS, United Kingdom
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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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Mentovich ED, Belgorodsky B, Richter S. Resolving the Mystery of the Elusive Peak: Negative Differential Resistance in Redox Proteins. J Phys Chem Lett 2011; 2:1125-1128. [PMID: 26295313 DOI: 10.1021/jz200304s] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Vertical molecular transistors are used to explain the nonconformal electron transfer results obtained for redox proteins. The transport characteristics of a negative differential resistance peak as appears in the transport data of azurin and its nonredox derivative are explored. A correlation between the peak and its redox center is demonstrated.
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Affiliation(s)
- Elad D Mentovich
- †School of Chemistry, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
- ‡University Center for Nanoscience and Nanotechnology, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
| | - Bogdan Belgorodsky
- †School of Chemistry, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
| | - Shachar Richter
- †School of Chemistry, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
- ‡University Center for Nanoscience and Nanotechnology, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
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Blanco-Rodríguez AM, Di Bilio AJ, Shih C, Museth AK, Clark IP, Towrie M, Cannizzo A, Sudhamsu J, Crane BR, Sýkora J, Winkler JR, Gray HB, Záliš S, Vlček A. Phototriggering electron flow through Re(I)-modified Pseudomonas aeruginosa azurins. Chemistry 2011; 17:5350-61. [PMID: 21469225 DOI: 10.1002/chem.201002162] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Revised: 12/12/2010] [Indexed: 11/07/2022]
Abstract
The [Re(I)(CO)(3)(4,7-dimethyl-1,10-phenanthroline)(histidine-124)(tryptophan-122)] complex, denoted [Re(I)(dmp)(W122)], of Pseudomonas aeruginosa azurin behaves as a single photoactive unit that triggers very fast electron transfer (ET) from a distant (2 nm) Cu(I) center in the protein. Analysis of time-resolved (ps-μs) IR spectroscopic and kinetics data collected on [Re(I)(dmp)(W122)AzM] (in which M=Zn(II), Cu(II), Cu(I); Az=azurin) and position-122 tyrosine (Y), phenylalanine (F), and lysine (K) mutants, together with excited-state DFT/time-dependent (TD)DFT calculations and X-ray structural characterization, reveal the character, energetics, and dynamics of the relevant electronic states of the [Re(I)(dmp)(W122)] unit and a cascade of photoinduced ET and relaxation steps in the corresponding Re-azurins. Optical population of [Re(I)(imidazole-H124)(CO)(3)]→dmp (1)CT states (CT=charge transfer) is followed by around 110 fs intersystem crossing and about 600 ps structural relaxation to a (3)CT state. The IR spectrum indicates a mixed Re(I)(CO)(3),A→dmp/π→π(*)(dmp) character for aromatic amino acids A122 (A=W, Y, F) and Re(I)(CO)(3)→dmp metal-ligand charge transfer (MLCT) for [Re(I)(dmp)(K122)AzCu(II)]. In a few ns, the (3)CT state of [Re(I)(dmp)(W122)AzM] establishes an equilibrium with the [Re(I)(dmp(.-))(W122(.+))AzM] charge-separated state, (3)CS, whereas the (3)CT state of the other Y, F, and K122 proteins decays to the ground state. In addition to this main pathway, (3)CS is populated by fs- and ps-W(indole)→Re(II) ET from (1)CT and the initially "hot" (3)CT states, respectively. The (3)CS state undergoes a tens-of-ns dmp(.-)→W122(.+) ET recombination leading to the ground state or, in the case of the Cu(I) azurin, a competitively fast (≈30 ns over 1.12 nm) Cu(I)→W(.+) ET, to give [Re(I)(dmp(.-))(W122)AzCu(II)]. The overall photoinduced Cu(I)→Re(dmp) ET through [Re(I)(dmp)(W122)AzCu(I)] occurs over a 2 nm distance in <50 ns after excitation, with the intervening fast (3)CT-(3)CS equilibrium being the principal accelerating factor. No reaction was observed for the three Y, F, and K122 analogues. Although the presence of [Re(dmp)(W122)AzCu(II)] oligomers in solution was documented by mass spectrometry and phosphorescence anisotropy, the kinetics data do not indicate any significant interference from the intermolecular ET steps. The ground-state dmp-indole π-π interaction together with well-matched W/W(.+) and excited-state [Re(II)(CO)(3)(dmp(.-))]/[Re(I)(CO)(3)(dmp(.-))] potentials that result in very rapid electron interchange and (3)CT-(3)CS energetic proximity, are the main factors responsible for the unique ET behavior of [Re(I)(dmp)(W122)]-containing azurins.
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Affiliation(s)
- Ana María Blanco-Rodríguez
- Queen Mary University of London, School of Biological and Chemical Sciences, Mile End Road, London E1 4NS, UK
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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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Electron Tunneling through Pseudomonas aeruginosa Azurins on SAM Gold Electrodes. Inorganica Chim Acta 2008; 361:1095-1099. [PMID: 19262679 DOI: 10.1016/j.ica.2007.08.022] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Robust voltammetric responses were obtained for wild-type and Y72F/H83Q/Q107H/Y108F azurins adsorbed on CH(3)(CH(2))(n)SH:HO(CH(2))(m)SH (n=m=4,6,8,11; n=13,15 m=11) self-assembled monolayer (SAM) gold electrodes in acidic solution (pH 4.6) at high ionic strengths. Electron-transfer (ET) rates do not vary substantially with ionic strength, suggesting that the SAM methyl headgroup binds to azurin by hydrophobic interactions. The voltammetric responses for both proteins at higher pH values (>4.6 to 11) also were strong. A binding model in which the SAM hydroxyl headgroup interacts with the Asn47 carboxamide accounts for the relatively strong coupling to the copper center that can be inferred from the ET rates. Of particular interest is the finding that rate constants for electron tunneling through n = 8, 13 SAMs are higher at pH 11 than those at pH 4.6, possibly owing to enhanced coupling of the SAM to Asn 47 caused by deprotonation of nearby surface residues.
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