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Rajbongshi J, Das DK, Mazumdar S. Spectroscopic and electrochemical studies of the pH-Induced transition in the CuA centre from Thermus thermophilus. Inorganica Chim Acta 2022. [DOI: 10.1016/j.ica.2021.120749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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2
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Khvorost TA, Beliaev LY, Masaoka Y, Hidaka T, Myasnikova OS, Ostras AS, Bogachev NA, Skripkin MY, Panov MS, Ryazantsev MN, Nagasawa Y, Mereshchenko AS. Ultrafast Excited-State Dynamics of CuBr 3- Complex Studied with Sub-20 fs Resolution. J Phys Chem B 2021; 125:7213-7221. [PMID: 34170695 DOI: 10.1021/acs.jpcb.1c03797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ultrafast excited-state dynamics of CuBr3- complex was studied in acetonitrile and dichloromethane solutions using femtosecond transient absorption spectroscopy with 18 fs temporal resolution and quantum-chemical DFT calculations. Upon 640 nm excitation, the CuBr3- complex is promoted to the ligand-to-metal charge transfer (LMCT) state, which then shortly undergoes internal conversion into the vibrationally hot ligand field (LF) excited state with time constants of 30 and 40 fs in acetonitrile and dichloromethane, respectively. The LF state nonradiatively relaxes into the ground state in 2.6 and 7.3 ps in acetonitrile and dichloromethane, respectively. Internal conversion of the LF state is accompanied by vibrational relaxation that occurs on the same time scale. Based on the analysis of coherent oscillations and quantum-chemical calculations, the predominant forms of the CuBr3- complex in acetonitrile and dichloromethane solutions were revealed. In acetonitrile, the CuBr3- complex exists as [CuBr3(CH3CN)2]-, whereas three forms of this complex, [CuBr3CH2Cl2]-, [CuBr3(CH2Cl2)2]-, and [CuBr3(CH2Cl2)3]-, are present in equilibrium in dichloromethane.
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Affiliation(s)
- Taras A Khvorost
- Saint-Petersburg State University, University Emb. 7/9, St. Petersburg 199034, Russia.,ITMO University, Birzhevaya l. 4, St. Petersburg 199034, Russia
| | - Leonid Yu Beliaev
- Saint-Petersburg State University, University Emb. 7/9, St. Petersburg 199034, Russia.,DTU Fotonik, Department of Photonics Engineering, Technical University of Denmark, Ørsteds Plads 343, DK-2800 Kgs. Lyngby, Denmark
| | - Yuto Masaoka
- College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Tsubasa Hidaka
- College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Olesya S Myasnikova
- Saint-Petersburg State University, University Emb. 7/9, St. Petersburg 199034, Russia
| | - Alexey S Ostras
- Saint-Petersburg State University, University Emb. 7/9, St. Petersburg 199034, Russia
| | - Nikita A Bogachev
- Saint-Petersburg State University, University Emb. 7/9, St. Petersburg 199034, Russia
| | - Mikhail Yu Skripkin
- Saint-Petersburg State University, University Emb. 7/9, St. Petersburg 199034, Russia
| | - Maxim S Panov
- Saint-Petersburg State University, University Emb. 7/9, St. Petersburg 199034, Russia
| | - Mikhail N Ryazantsev
- Saint-Petersburg State University, University Emb. 7/9, St. Petersburg 199034, Russia.,Saint Petersburg Academic University, ul. Khlopina 8/3, St. Petersburg 194021, Russia
| | - Yutaka Nagasawa
- College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Andrey S Mereshchenko
- Saint-Petersburg State University, University Emb. 7/9, St. Petersburg 199034, Russia
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3
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Mereshchenko AS, Myasnikova OS, Olshin PK, Matveev SM, Panov MS, Kochemirovsky VA, Skripkin MY, Tarnovsky AN. Ultrafast Excited-State Dynamics of Ligand-Field and Ligand-to-Metal Charge-Transfer States of CuCl42– in Solution: A Detailed Transient Absorption Study. J Phys Chem B 2018; 122:10558-10571. [DOI: 10.1021/acs.jpcb.8b06901] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Andrey S. Mereshchenko
- Saint-Petersburg State University, University Embankment 7/9, St. Petersburg 199034, Russia
- Department of Chemistry and the Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States
| | - Olesya S. Myasnikova
- Saint-Petersburg State University, University Embankment 7/9, St. Petersburg 199034, Russia
| | - Pavel K. Olshin
- Saint-Petersburg State University, University Embankment 7/9, St. Petersburg 199034, Russia
| | - Sergey M. Matveev
- Department of Chemistry and the Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States
| | - Maxim S. Panov
- Saint-Petersburg State University, University Embankment 7/9, St. Petersburg 199034, Russia
- Department of Chemistry and the Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States
| | | | - Mikhail Yu. Skripkin
- Saint-Petersburg State University, University Embankment 7/9, St. Petersburg 199034, Russia
| | - Alexander N. Tarnovsky
- Department of Chemistry and the Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States
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4
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Mereshchenko AS, Olshin PK, Myasnikova OS, Panov MS, Kochemirovsky VA, Skripkin MY, Moroz PN, Zamkov M, Tarnovsky AN. Ultrafast Photochemistry of Copper(II) Monochlorocomplexes in Methanol and Acetonitrile by Broadband Deep-UV-to-Near-IR Femtosecond Transient Absorption Spectroscopy. J Phys Chem A 2016; 120:1833-44. [PMID: 26901567 DOI: 10.1021/acs.jpca.5b12509] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Photochemistry of copper(II) monochlorocomplexes in methanol and acetonitrile solutions is studied by UV-pump/broadband deep-UV-to-near-IR probe femtosecond transient absorption spectroscopy. Upon 255 and 266 nm excitation, the complexes in acetonitrile and methanol, respectively, are promoted to the excited ligand-to-metal charge transfer (LMCT) state, which has a short (sub-250 fs) lifetime. From the LMCT state, the complexes decay via internal conversion to lower-lying ligand field (LF) d-d excited states or the vibrationally hot ground electronic state. A minor fraction of the excited complexes relaxes to the LF electronic excited states, which are relatively long-lived with lifetimes >1 ns. Also, in methanol solutions, about 3% of the LMCT-excited copper(II) monochlorocomplexes dissociate forming copper(I) solvatocomplexes and chlorine atoms, which then further react forming long-lived photoproducts. In acetonitrile, about 50% of the LMCT-excited copper(II) monochlorocomplexes dissociate forming radical and ionic products in a ratio of 3:2. Another minor process observed following excitation only in methanol solutions is the re-equilibration between several forms of the copper(II) ground-state complexes present in solutions. This re-equilibration occurs on a time scale from sub-nanoseconds to nanoseconds.
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Affiliation(s)
- Andrey S Mereshchenko
- Saint-Petersburg State University , 7/9 Universitetskaya nab., St. Petersburg, 199034 Russia
| | - Pavel K Olshin
- Saint-Petersburg State University , 7/9 Universitetskaya nab., St. Petersburg, 199034 Russia
| | - Olesya S Myasnikova
- Saint-Petersburg State University , 7/9 Universitetskaya nab., St. Petersburg, 199034 Russia
| | - Maxim S Panov
- Saint-Petersburg State University , 7/9 Universitetskaya nab., St. Petersburg, 199034 Russia
| | | | - Mikhail Yu Skripkin
- Saint-Petersburg State University , 7/9 Universitetskaya nab., St. Petersburg, 199034 Russia
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5
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Photochemistry of copper(II) chlorocomplexes in acetonitrile: Trapping the ligand-to-metal charge transfer excited state relaxations pathways. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2014.10.016] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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6
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Kaas Q, Craik DJ. NMR of plant proteins. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2013; 71:1-34. [PMID: 23611313 DOI: 10.1016/j.pnmrs.2013.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 01/21/2013] [Indexed: 06/02/2023]
Affiliation(s)
- Quentin Kaas
- The University of Queensland, Institute for Molecular Bioscience, Brisbane, Queensland 4072, Australia
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Ranieri A, Battistuzzi G, Borsari M, Bortolotti CA, Di Rocco G, Sola M. pH and solvent H/D isotope effects on the thermodynamics and kinetics of electron transfer for electrode-immobilized native and urea-unfolded stellacyanin. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:15087-15094. [PMID: 23009339 DOI: 10.1021/la303363h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The thermodynamics of Cu(II) to Cu(I) reduction and the kinetics of the electron transfer (ET) process for Rhus vernicifera stellacyanin (STC) immobilized on a decane-1-thiol coated gold electrode have been measured through cyclic voltammetry at varying pH and temperature, in the presence of urea and in D(2)O. Immobilized STC undergoes a limited conformational change that mainly results in an enhanced exposure of one or both copper binding histidines to solvent which slightly stabilizes the cupric state and increases histidine basicity. The large immobilization-induced increase in the pK(a) for the acid transition (from 4.5 to 6.3) makes this electrode-SAM-protein construct an attractive candidate as a biomolecular ET switch operating near neutral pH in molecular electronics. Such a potential interest is increased by the robustness of this interface against chemical unfolding as it undergoes only moderate changes in the reduction thermodynamics and in the ET rate in the presence of up to 8 M urea. The sensitivity of these parameters to solvent H/D isotope effects testifies to the role of protein solvation as effector of the thermodynamics and kinetics of ET.
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Affiliation(s)
- Antonio Ranieri
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Modena, Italy
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Ruan XM, Luo F, Li DD, Zhang J, Liu ZH, Xu WL, Huang GQ, Li XB. Cotton BCP genes encoding putative blue copper-binding proteins are functionally expressed in fiber development and involved in response to high-salinity and heavy metal stresses. PHYSIOLOGIA PLANTARUM 2011; 141:71-83. [PMID: 21029107 DOI: 10.1111/j.1399-3054.2010.01420.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Copper is vitally required for plants at low concentrations but extremely toxic for plants at elevated concentrations. Plants have evolved a series of mechanisms to prevent the consequences of the excess or deficit of copper. These mechanisms require copper-interacting proteins involved in copper trafficking. Blue copper-binding proteins (BCPs) are a class of copper proteins containing one blue copper-binding domain binding a single type I copper. To investigate the role of BCPs in plant development and in response to stresses, we isolated nine cDNAs encoding the putative blue copper-binding proteins (GhBCPs) from cotton (Gossypium hirsutum). Meanwhile, four corresponding genes (including GhBCP1-GhBCP4), which contain a single intron inserted in their conserved position, were isolated from cotton genome. Quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) analysis indicated that the nine GhBCP genes are differentially expressed in cotton tissues. Among them, GhBCP1 and GhBCP4 were predominantly expressed in fibers, while the transcripts of GhBCP2 and GhBCP3 were accumulated at relatively high levels in fibers. These four genes were strongly expressed in early fiber elongation, but dramatically declined with further fiber development. In addition, these GhBCP genes were upregulated in fibers by Cu(2+) , Zn(2+) , high-salinity and drought stresses, but downregulated in fibers by Al(3+) treatment. Overexpression of GhBCP1 and GhBCP4 in yeast (Schizosaccharomyces pombe) significantly increased the cell growth rate under Cu(2+) , Zn(2+) and high-salinity stresses. These results suggested that these GhBCPs may participate in the regulation of fiber development and in response to high-salinity and heavy metal stresses in cotton.
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Affiliation(s)
- Xiang-Mei Ruan
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, HuaZhong Normal University, Wuhan 430079, China
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9
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Guzzi R, Sportelli L, Sato K, Cannistraro S, Dennison C. Thermal unfolding studies of a phytocyanin. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2008; 1784:1997-2003. [DOI: 10.1016/j.bbapap.2008.07.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2008] [Revised: 07/03/2008] [Accepted: 07/03/2008] [Indexed: 10/21/2022]
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10
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Battistuzzi G, Bellei M, Dennison C, Di Rocco G, Sato K, Sola M, Yanagisawa S. Thermodynamics of the alkaline transition in phytocyanins. J Biol Inorg Chem 2007; 12:895-900. [PMID: 17569996 DOI: 10.1007/s00775-007-0245-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2007] [Accepted: 04/29/2007] [Indexed: 10/23/2022]
Abstract
The thermodynamics of the alkaline transition which influences the spectral and redox properties of the type 1 copper center in phytocyanins has been determined spectroscopically. The proteins investigated include Rhus vernicifera stellacyanin, cucumber basic protein and its Met89Gln variant, and umecyanin, the stellacyanin from horseradish roots, along with its Gln95Met variant. The changes in reaction enthalpy and entropy within the protein series show partial compensatory behavior. Thus, the reaction free energy change (hence the pK (a) value) is rather variable. This indicates that species-dependent differences in reaction thermodynamics, although containing an important contribution from changes in the hydrogen-bonding network of water molecules in the hydration sphere of the protein (which feature enthalpy-entropy compensation), are to a large extent protein-based. The data for axial ligand variants are consistent with the hypothesis of a copper-binding His as the deprotonating residue responsible for this transition.
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Affiliation(s)
- Gianantonio Battistuzzi
- Department of Chemistry, University of Modena and Reggio Emilia, Via Campi 183, 41100 Modena, Italy
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11
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Delfino I, Manzoni C, Sato K, Dennison C, Cerullo G, Cannistraro S. Ultrafast Pump−Probe Study of Excited-State Charge-Transfer Dynamics in Umecyanin from Horseradish Root. J Phys Chem B 2006; 110:17252-9. [PMID: 16928024 DOI: 10.1021/jp062904y] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have applied femtosecond pump-probe spectroscopy to investigate the excited-state dynamics of umecyanin from horseradish roots, by exciting its 600-nm ligand-to-metal charge-transfer band with a 15-fs pulse and probing over a broad range in the visible region. The decay of the pump-induced ground-state bleaching is modulated by clearly visible oscillations and occurs exponentially with a time constant depending on the observed spectral component of the transmission difference signal, ranging from 270 fs up to 700 fs. The slower decaying process characterizes the spectral component corresponding to the metal-to-ligand charge-transfer transition. The excited-state decay rate is significantly lower than in other blue copper proteins, probably because of the larger energy gap between ligand- and metal-based orbitals in umecyanin. Wavelength dependence of the recovery times could be due to either the excitation of several transitions or the occurrence of intramolecular vibrational relaxation within the excited state. We also find evidence of a hot ground-state absorption, at 700 nm, persisting for several picoseconds. The vibrational coherence induced by the ultrashort pump pulse allows vibrational activity to be observed, mainly in the ground state, as expected in a system with fast excited-state decay. However, we find evidence of a rapidly damped oscillation, which we assign to the excited state. Finally, the Fourier transform of the oscillatory component of the signal presents additional bands in the low-frequency region which are assigned to collective motions of the protein.
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Affiliation(s)
- Ines Delfino
- Biophysics and Nanoscience Centre, CNISM - Università della Tuscia, I-01100 Viterbo, Italy
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13
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Yanagisawa S, Dennison C. Reduction Potential Tuning at a Type 1 Copper Site Does Not Compromise Electron Transfer Reactivity. J Am Chem Soc 2005; 127:16453-9. [PMID: 16305231 DOI: 10.1021/ja054426v] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Type 1 (T1) copper sites promote biological electron transfer (ET) and typically possess a weakly coordinated thioether sulfur from an axial Met [Cu(II)-Sdelta approximately 2.6 to 3.3 A] along with the conserved His2Cys equatorial ligands. A strong axial bond [Cu(II)-Oepsilon1 approximately 2.2 A] is sometimes provided by a Gln (as in the stellacyanins), and the axial ligand can be absent (a Val, Leu or Phe in the axial position) as in ceruloplasmin, Fet3p, fungal laccases and some plantacyanins (PLTs). Cucumber basic protein (CBP) is a PLT which has a relatively short Cu(II)-S(Met89) axial bond (2.6 A). The Met89Gln variant of CBP has an electron self-exchange (ESE) rate constant (k(ese), a measure of intrinsic ET reactivity) approximately 7 times lower than that of the wild-type protein. The Met89Val mutation to CBP results in a 2-fold increase in k(ese). As the axial interaction decreases from strong Oepsilon1 of Gln to relatively weak Sdelta of Met to no ligand (Val), ESE reactivity is therefore enhanced by approximately 1 order of magnitude while the reduction potential increases by approximately 350 mV. The variable coordination position at this ubiquitous ET site provides a mechanism for tuning the driving force to optimize ET with the correct partner without significantly compromising intrinsic reactivity. The enhanced reactivity of a three-coordinate T1 copper site will facilitate intramolecular ET in fungal laccases and Fet3p.
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Affiliation(s)
- Sachiko Yanagisawa
- Institute for Cell and Molecular Biosciences, Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne, NE2 4HH, UK
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Koch M, Velarde M, Harrison MD, Echt S, Fischer M, Messerschmidt A, Dennison C. Crystal structures of oxidized and reduced stellacyanin from horseradish roots. J Am Chem Soc 2005; 127:158-66. [PMID: 15631465 DOI: 10.1021/ja046184p] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Umecyanin (UMC) is a type 1 copper-containing protein which originates from horseradish roots and belongs to the stellacyanin subclass of the phytocyanins, a ubiquitous family of plant cupredoxins. The crystal structures of Cu(II) and Cu(I) UMC have been determined at 1.9 and 1.8 A, respectively. The protein has an overall fold similar to those of other phytocyanins. At the active site the cupric ion is coordinated by the N(delta1) atoms of His44 and His90, the S(gamma) of Cys85, and the O(epsilon)(1) of Gln95 in a distorted tetrahedral geometry. Both His ligands are solvent exposed and are surrounded by nonpolar and polar side chains on the protein surface. Thus, UMC does not possess a distinct hydrophobic patch close to the active site in contrast to almost all other cupredoxins. UMC has a large surface acidic patch situated approximately 10-30 A from the active site. The structure of Cu(I) UMC is the first determined for a reduced phytocyanin and demonstrates that the coordination environment of the cuprous ion is more trigonal pyramidal. This subtle change in geometry is primarily due to the Cu-N(delta1)(His44) and Cu-O(epsilon1)(Gln95) bond lengths increasing from 2.0 and 2.3 A in Cu(II) UMC to 2.2 and 2.5 A, respectively, in the reduced form, as a consequence of slight rotations of the His44 and Gln95 side chains. The limited structural changes upon redox interconversion at the active site of this stellacyanin are analogous to those observed in a typical type 1 copper site with an axial Met ligand and along with its surface features suggest a role for UMC in interprotein electron transfer.
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Affiliation(s)
- Michael Koch
- Abteilung Strukturforschung, Max-Planck-Institut für Biochemie, Am Klopferspitz 18, D-82152 Martinsried, Germany
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15
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Abstract
The shortest known type 1 copper binding loop (that of amicyanin, Ami) has been introduced into three different cupredoxin beta-barrel scaffolds. All of the loop-contraction variants possess copper centers with authentic type 1 properties and are redox active. The Cu(II) and Co(II) sites experience only small structural alterations upon loop contraction with the largest changes in the azurin variant (AzAmi), which can be ascribed to the removal of a hydrogen bond to the coordinating thiolate sulfur of the Cys ligand. In all cases, loop contraction leads to an increase in the pK(a) of the His ligand found on the loop in the reduced proteins, and in the pseudoazurin (Paz) and plastocyanin (Pc) variants the values are almost identical to that of Ami ( approximately 6.7). Thus, in Paz, Pc, and Ami, the length of this loop tunes the pK(a) of the His ligand. In the AzAmi variant, the pK(a) is 5.5, which is considerably higher than the estimated value for Az (<2), and other controlling factors, along with loop length, are involved. The reduction potentials of the loop-contraction variants are all lower than those of the wild-type proteins by approximately 30-60 mV, and thus this property of a type 1 copper site is fine-tuned by the C-terminal loop. The electron self-exchange rate constant of Paz is significantly diminished by the introduction of a shorter loop. However, in PcAmi only a 2-fold decrease is observed and in AzAmi there is no effect, and thus in these two cupredoxins loop contraction does not significantly influence electron-transfer reactivity. Loop contraction provides an active site environment in all of the cupredoxins which is preferable for Cu(II), whereas previous loop elongation experiments always favored the cuprous site. Thus, the ligand-containing loop plays an important role in tuning the entatic nature of a type 1 copper center.
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Affiliation(s)
- Sachiko Yanagisawa
- School of Natural Sciences, Bedson Building, University of Newcastle upon Tyne, Newcastle upon Tyne, NE1 7RU, UK
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Harrison MD, Dennison C. Characterization of Arabidopsis thaliana stellacyanin: A comparison with umecyanin. Proteins 2004; 55:426-35. [PMID: 15048833 DOI: 10.1002/prot.20017] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The cupredoxin domain of a putative type 1 blue copper protein (BCB) from Arabidopsis thaliana was overexpressed and purified. A recursive polymerase chain reaction method was used to synthesize an artificial coding region for the cupredoxin domain of horseradish stellacyanin (commonly known as umecyanin), prior to overexpression and purification. The recombinant proteins were refolded from inclusion bodies and reconstituted with copper, and their in vitro characteristics were studied. Recombinant umecyanin, which is nonglycosylated, has identical spectroscopic and redox properties to the native protein. The UV/Vis and EPR spectra of recombinant BCB and umecyanin demonstrate that they have comparable axial type 1 copper binding sites. Paramagnetic (1)H NMR spectroscopy highlights the similarity between the active site architectures of BCB and umecyanin. The reduction potential of recombinant BCB is 252 mV, compared to 293 mV for recombinant umecyanin. Identical pK(a) values of 9.7 are obtained for the alkaline transitions in both proteins. This study demonstrates that BCB is the A. thaliana stellacyanin and the results form the biochemical basis for a discussion of BCB function in the model vascular plant.
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Affiliation(s)
- Mark D Harrison
- School of Natural Sciences, University of Newcastle upon Tyne, Newcastle upon Tyne, United Kingdom
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Dennison C, Harrison MD. The Active-Site Structure of Umecyanin, the Stellacyanin from Horseradish Roots. J Am Chem Soc 2004; 126:2481-9. [PMID: 14982457 DOI: 10.1021/ja0375378] [Citation(s) in RCA: 20] [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
The type 1 copper sites of cupredoxins typically have a His(2)Cys equatorial ligand set with a weakly interacting axial Met, giving a distorted tetrahedral geometry. Natural variations to this coordination environment are known, and we have utilized paramagnetic (1)H NMR spectroscopy to study the active-site structure of umecyanin (UMC), a stellacyanin with an axial Gln ligand. The assigned spectra of the Cu(II) UMC and its Ni(II) derivative [Ni(II) UMC] demonstrate that this protein has the typical His(2)Cys equatorial coordination observed in other structurally characterized cupredoxins. The NMR spectrum of the Cu(II) protein does not exhibit any paramagnetically shifted resonances from the axial ligand, showing that this residue does not contribute to the singly occupied molecular orbital (SOMO) in Cu(II) UMC. The assigned paramagnetic (1)H NMR spectrum of Ni(II) UMC demonstrates that the axial Gln ligand coordinates in a monodentate fashion via its side-chain amide oxygen atom. The alkaline transition, a feature common to stellacyanins, influences all of the ligating residues but does not alter the coordination mode of the axial Gln ligand in UMC. The structural features which result in Cu(II) UMC possessing a classic type 1 site as compared to the perturbed type 1 center observed for other stellacyanins do not have a significant influence on the paramagnetic (1)H NMR spectra of the Cu(II) or Ni(II) proteins.
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Affiliation(s)
- Christopher Dennison
- School of Natural Sciences, Bedson Building, University of Newcastle upon Tyne, Newcastle upon Tyne, NE1 7RU, UK.
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18
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Hass MAS, Thuesen MH, Christensen HEM, Led JJ. Characterization of μs−ms Dynamics of Proteins Using a Combined Analysis of 15N NMR Relaxation and Chemical Shift: Conformational Exchange in Plastocyanin Induced by Histidine Protonations. J Am Chem Soc 2003; 126:753-65. [PMID: 14733549 DOI: 10.1021/ja030366m] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An approach is presented that allows a detailed, quantitative characterization of conformational exchange processes in proteins on the micros-ms time scale. The approach relies on a combined analysis of NMR relaxation rates and chemical shift changes and requires that the chemical shift of the exchanging species can be determined independently of the relaxation rates. The applicability of the approach is demonstrated by a detailed analysis of the conformational exchange processes previously observed in the reduced form of the blue copper protein, plastocyanin from the cyanobacteria Anabaena variabilis (A.v. PCu) (Ma, L.; Hass, M. A. S.; Vierick, N.; Kristensen, S. M.; Ulstrup, J.; Led, J. J. Biochemistry 2003, 42, 320-330). The R1 and R2 relaxation rates of the backbone 15N nuclei were measured at a series of pH and temperatures on an 15N labeled sample of A.v. PCu, and the 15N chemical shifts were obtained from a series of HSQC spectra recorded in the pH range from 4 to 8. From the R1 and R2 relaxation rates, the contribution, Rex, to the transverse relaxation caused by the exchanges between the different allo-states of the protein were determined. Specifically, it is demonstrated that accurate Rex terms can be obtained from the R1 and R2 rates alone in the case of relatively rigid proteins with a small rotational anisotropy. The Rex terms belonging to the same exchange process were identified on the basis of their pH dependences. Subsequently the identifications were confirmed quantitatively by the correlation between the Rex terms and the corresponding chemical shift differences of the exchanging species. By this approach, the Rex terms of 15N nuclei belonging to contiguous regions in the protein could be assigned to the same exchange process. Furthermore, the analysis of the exchange terms shows that the observed micros-ms dynamics in A.v. PCu are caused primarily by the protonation/deprotonation of two histidine residues, His92 and His61, His92 being ligated to the Cu(I) ion. Also the exchange rate of the protonation/deprotonation process of His92 and its pH and temperature dependences were determined, revealing a reaction pathway that is more complex than a simple specific-acid/base catalysis. Finally, the approach allows a differentiation between two-site and multiple-site exchange processes, thus revealing that the protonation/deprotonation of His61 is at least a three-site exchange process. Overall, the approach makes it feasible to obtain exchange rates that are sufficiently accurate and versatile for studies of the kinetics and the mechanisms of local protein dynamics on the sub-millisecond time scale.
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Affiliation(s)
- Mathias A S Hass
- Department of Chemistry, University of Copenhagen, The H. C. Ørsted Institute, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
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Battistuzzi G, Di Rocco G, Leonardi A, Sola M. 1H NMR of native and azide-inhibited laccase from Rhus vernicifera. J Inorg Biochem 2003; 96:503-6. [PMID: 13678817 DOI: 10.1016/s0162-0134(03)00277-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The 1H NMR spectra of the fully oxidized Rhus vernicifera laccase and of its 1:1 and 2:1 azide adducts are reported for the first time. These spectra, which are the first so far reported for a multi copper oxidase, contain a number of broad hyperfine-shifted resonances in the high frequency region of the spectrum, which are attributed to the metal binding residues of the mononuclear T1 center. The differences between the patterns of the hyperfine resonances of the free enzyme and its azide derivatives suggest that the alterations in the structural properties of the T3 site induced by the binding of the first azide molecule induce a limited alteration of the spin density distribution over the T1 copper ligands. Overall, these data demonstrate that 1H NMR can be fruitfully applied to characterize the electronic properties of the metal sites of blue oxidases at room temperature.
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Affiliation(s)
- Gianantonio Battistuzzi
- Department of Chemistry, University of Modena and Reggio Emilia, via Campi 183, 41100 Modena, Italy.
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Dennison C, Harrison MD, Lawler AT. Alkaline transition of phytocyanins: a comparison of stellacyanin and umecyanin. Biochem J 2003; 371:377-83. [PMID: 12529171 PMCID: PMC1223298 DOI: 10.1042/bj20021869] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2002] [Revised: 01/08/2003] [Accepted: 01/15/2003] [Indexed: 11/17/2022]
Abstract
The effect of pH on Cu(I) and Cu(II) forms of the isolated soluble domain of the stellacyanin from Rhus vernicifera (SCu), the Japanese lacquer tree, has been studied by electronic and NMR spectroscopy and using direct electrochemical measurements. A pK(a) value of 10.1-10.4 is observed for the alkaline transition in this oxidized phytocyanin and results in a slightly altered active-site structure, as indicated by changes in the visible and paramagnetic (1)H NMR spectra. Electrochemical studies show that the pK(a) value for this transition in SCu(I) (reduced SCu) is 11.0. These results are compared with those recently obtained for other phytocyanins, and in particular umecyanin. In all cases, the alkaline transition is caused by the deprotonation of the surface lysine residue adjacent to the axial ligand. This lysine residue is completely conserved in known phytocyanin sequences. Also highlighted in these studies are the remarkable active-site similarities between stellacyanin and umecyanin.
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Affiliation(s)
- Christopher Dennison
- School of Natural Sciences, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU, UK.
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Banci L, Pierattelli R, Vila AJ. Nuclear magnetic resonance spectroscopy studies on copper proteins. ADVANCES IN PROTEIN CHEMISTRY 2003; 60:397-449. [PMID: 12418182 DOI: 10.1016/s0065-3233(02)60058-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Affiliation(s)
- Lucia Banci
- CERM, University of Florence, 50019 Sesto Fiorentino, Italy
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Dennison C, Sato K. Paramagnetic 1H NMR spectrum of nickel(II) pseudoazurin: investigation of the active site structure and the acid and alkaline transitions. Inorg Chem 2002; 41:6662-72. [PMID: 12470061 DOI: 10.1021/ic020303p] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The paramagnetic (1)H NMR spectrum of Ni(II) pseudoazurin [(PA)Ni(II)] possesses a number of resonances exhibiting sizable Fermi-contact shifts. These have been assigned to protons associated with the four ligating amino acids, His40, Cys78, His81, and Met86. The shifts experienced by the C(gamma)H protons of the axial Met86 ligand are unprecedented compared to other Ni(II)- and Co(II)-substituted cupredoxins (the C(gamma)(1)H signal is found at 432.5 ppm at 25 degrees C). The large shift of protons of the axial Met86 ligand highlights a strong Ni(II)-S(Met) interaction in (PA)Ni(II). The paramagnetic (1)H NMR spectrum of (PA)Ni(II) is altered by decreasing and increasing the pH value from 8.0. At acidic pH a number of the hyperfine-shifted resonances undergo limited changes in their chemical shift values. This effect is assigned to the surface His6 residue whose protonation results in a structural modification of the active site. Increasing the pH value from 8.0 has a more significant effect on the paramagnetic (1)H NMR spectrum of (PA)Ni(II), and the alkaline transition can now be assigned to two surface lysine residues close to the active site of the protein. The effect of altering pH on the (1)H NMR spectrum of Ni(II) pseudoazurin is smaller than that previously observed in the Cu(II) protein indicating more limited structural rearrangements at the non-native metal site.
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