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Rivera JJ, Trinh C, Kim JE. Photoinduced Electron Transfer from the Tryptophan Triplet State in Zn-Azurin. ACS PHYSICAL CHEMISTRY AU 2022; 3:63-73. [PMID: 36718260 PMCID: PMC9881450 DOI: 10.1021/acsphyschemau.2c00042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/18/2022] [Accepted: 10/19/2022] [Indexed: 11/30/2022]
Abstract
Tryptophan is one of few residues that participates in biological electron transfer reactions. Upon substitution of the native Cu2+ center with Zn2+ in the blue-copper protein azurin, a long-lived tryptophan neutral radical can be photogenerated. We report the following quantum yield values for Zn-substituted azurin in the presence of the electron acceptor Cu(II)-azurin: formation of the tryptophan neutral radical (Φrad), electron transfer (ΦET), fluorescence (Φfluo), and phosphorescence (Φphos), as well as the efficiency of proton transfer of the cation radical (ΦPT). Increasing the concentration of the electron acceptor increased Φrad and ΦET values and decreased Φphos without affecting Φfluo. At all concentrations of the acceptor, the value of ΦPT was nearly unity. These observations indicate that the phosphorescent triplet state is the parent state of electron transfer and that nearly all electron transfer events lead to proton loss. Similar results regarding the parent state were obtained with a different electron acceptor, [Co(NH3)5Cl]2+; however, Stern-Volmer graphs revealed that [Co(NH3)5Cl]2+ was a more effective phosphorescence quencher (K SV = 230 000 M-1) compared to Cu(II)-azurin (K SV = 88 000 M-1). Competition experiments in the presence of both [Co(NH3)5Cl]2+ and Cu(II)-azurin suggested that [Co(NH3)5Cl]2+ is the preferred electron acceptor. Implications of these results in terms of quenching mechanisms are discussed.
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Yu Y, Marshall NM, Garner DK, Nilges MJ, Lu Y. Tuning reduction potentials of type 1 copper center in azurin by replacing a histidine ligand with its isostructural analogues. J Inorg Biochem 2022; 234:111863. [DOI: 10.1016/j.jinorgbio.2022.111863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 05/02/2022] [Accepted: 05/08/2022] [Indexed: 11/16/2022]
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3
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Baldacchini C, Bizzarri AR, Cannistraro S. Electron transfer, conduction and biorecognition properties of the redox metalloprotein Azurin assembled onto inorganic substrates. Eur Polym J 2016. [DOI: 10.1016/j.eurpolymj.2016.04.030] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Dahl EW, Szymczak NK. Hydrogen Bonds Dictate the Coordination Geometry of Copper: Characterization of a Square-Planar Copper(I) Complex. Angew Chem Int Ed Engl 2016; 55:3101-5. [PMID: 26822857 PMCID: PMC4804195 DOI: 10.1002/anie.201511527] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Indexed: 12/31/2022]
Abstract
6,6''-Bis(2,4,6-trimethylanilido)terpyridine (H2Tpy(NMes)) was prepared as a rigid, tridentate pincer ligand containing pendent anilines as hydrogen bond donor groups in the secondary coordination sphere. The coordination geometry of (H2 Tpy(NMes))copper(I)-halide (Cl, Br and I) complexes is dictated by the strength of the NH-halide hydrogen bond. The Cu(I)Cl and Cu(II)Cl complexes are nearly isostructural, the former presenting a highly unusual square-planar geometry about Cu(I) . The geometric constraints provided by secondary interactions are reminiscent of blue copper proteins where a constrained geometry, or entatic state, allows for extremely rapid Cu(I)/Cu(II) electron-transfer self-exchange rates. Cu(H2 Tpy(NMes))Cl shows similar fast electron transfer (≈10(5) m(-1) s(-1)) which is the same order of magnitude as biological systems.
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Affiliation(s)
- Eric W Dahl
- Department of Chemistry, University of Michigan, 930 N. University, Ann Arbor, MI, 48109, USA
| | - Nathaniel K Szymczak
- Department of Chemistry, University of Michigan, 930 N. University, Ann Arbor, MI, 48109, USA.
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Dahl EW, Szymczak NK. Hydrogen Bonds Dictate the Coordination Geometry of Copper: Characterization of a Square‐Planar Copper(I) Complex. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201511527] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Eric W. Dahl
- Department of Chemistry University of Michigan 930 N. University Ann Arbor MI 48109 USA
| | - Nathaniel K. Szymczak
- Department of Chemistry University of Michigan 930 N. University Ann Arbor MI 48109 USA
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Immobilization of azurin with retention of its native electrochemical properties at alkylsilane self-assembled monolayer modified indium tin oxide. Electrochim Acta 2012. [DOI: 10.1016/j.electacta.2012.08.044] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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7
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Warren JJ, Lancaster KM, Richards JH, Gray HB. Inner- and outer-sphere metal coordination in blue copper proteins. J Inorg Biochem 2012; 115:119-26. [PMID: 22658756 PMCID: PMC3434318 DOI: 10.1016/j.jinorgbio.2012.05.002] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Revised: 04/30/2012] [Accepted: 05/01/2012] [Indexed: 10/28/2022]
Abstract
Blue copper proteins (BCPs) comprise classic cases of Nature's profound control over the electronic structures and chemical reactivity of transition metal ions. Early studies of BCPs focused on their inner coordination spheres, that is, residues that directly coordinate Cu. Equally important are the electronic and geometric perturbations to these ligands provided by the outer coordination sphere. In this tribute to Hans Freeman, we review investigations that have advanced the understanding of how inner-sphere and outer-sphere coordination affects biological Cu properties.
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Affiliation(s)
- Jeffrey J Warren
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA
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Ullmann RT, Ullmann GM. Coupling of Protonation, Reduction, and Conformational Change in azurin from Pseudomonas aeruginosa Investigated with Free Energy Measures of Cooperativity. J Phys Chem B 2011; 115:10346-59. [DOI: 10.1021/jp204644h] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- R. Thomas Ullmann
- Structural Biology/Bioinformatics, University of Bayreuth, Universitätsstrasse 30, BGI, 95447 Bayreuth, Germany
| | - G. Matthias Ullmann
- Structural Biology/Bioinformatics, University of Bayreuth, Universitätsstrasse 30, BGI, 95447 Bayreuth, Germany
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Lancaster KM, Farver O, Wherland S, Crane EJ, Richards JH, Pecht I, Gray HB. Electron transfer reactivity of type zero Pseudomonas aeruginosa azurin. J Am Chem Soc 2011; 133:4865-73. [PMID: 21405124 PMCID: PMC3607328 DOI: 10.1021/ja1093919] [Citation(s) in RCA: 45] [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
Type zero copper is a hard-ligand analogue of the classical type 1 or blue site in copper proteins that function as electron transfer (ET) agents in photosynthesis and other biological processes. The EPR spectroscopic features of type zero Cu(II) are very similar to those of blue copper, although lacking the deep blue color, due to the absence of thiolate ligation. We have measured the rates of intramolecular ET from the pulse radiolytically generated C3-C26 disulfide radical anion to the Cu(II) in both type zero C112D/M121L and type 2 C112D Pseudomonas aeruginosa azurins in pH 7.0 aqueous solutions between 8 and 45 °C. We also have obtained rate/temperature (10-30 °C) profiles for ET reactions between these mutants and the wild-type azurin. Analysis of the rates and activation parameters for both intramolecular and intermolecular ET reactions indicates that the type zero copper reorganization energy falls in a range (0.9-1.1 eV) slightly above that for type 1 (0.7-0.8 eV), but substantially smaller than that for type 2 (>2 eV), consistent with XAS and EXAFS data that reveal minimal type zero site reorientation during redox cycling.
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Affiliation(s)
- Kyle M. Lancaster
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853
| | - Ole Farver
- Institute of Analytical Chemistry, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Scot Wherland
- Department of Chemistry, Washington State University, Pullman, WA 99164-4630
| | - Edward J. Crane
- Department of Chemistry, Pomona College, Claremont CA 91711-6338
| | - John H. Richards
- Beckman Institute, California Institute of Technology, Pasadena CA 91125
| | - Israel Pecht
- Department of Immunology, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Harry B. Gray
- Beckman Institute, California Institute of Technology, Pasadena CA 91125
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10
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Biological Outer-Sphere Coordination. MOLECULAR ELECTRONIC STRUCTURES OF TRANSITION METAL COMPLEXES I 2011. [DOI: 10.1007/430_2011_49] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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11
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Mukhopadhyay BP, Ghosh B, Bairagya HR, Nandi TK, Chakrabarti B, Bera AK. Molecular Modeling of the Ternary Complex of Rusticyanin-Cytochrome c4-Cytochrome Oxidase: An Insight to Possible H-Bond Mediated Recognition and Electron Transfer Reaction inT.ferrooxidans. J Biomol Struct Dyn 2008; 25:543-51. [DOI: 10.1080/07391102.2008.10507201] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Mukhopadhyay BP, Ghosh B, Bairagya HR, Bera AK, Nandi TK, Das SB. Modeling Study of Rusticyanin-Cytochrome C4Complex: An Insight to Possible H-Bond Mediated Recognition and Electron—Transfer Process. J Biomol Struct Dyn 2007; 25:157-64. [PMID: 17718594 DOI: 10.1080/07391102.2007.10507164] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Rusticyanin (RCy) mediated transfer of electron to Cytochrome C(4) (Cytc(4)) from the extracellular Fe(+2) ion is primarily involved in the Thiobacillus ferrooxidans induced bio-leaching of pyrite ore and also in the metabolism of this acidophilic bacteria. The modeling studies have revealed the two possible mode of RCy-Cytc(4) complexation involving nearly the same stabilization energy approximately -15 x 10(3) kJ/mol, one through N-terminal Asp 15 and another -C terminal Glu 121 of Cytc(4) with the Cu-bonded His 143 of RCy. The Asp 15:His 143 associated complex (DH) of Cytc(4)-RCy was stabilized by the intermolecular H-bonds of the carboxyl oxygen atoms O(delta1) and O(delta2) of Asp 15 with the Nepsilon-atom of His 143 and O(b) atoms of Ala 8 and Asp 5 (of Cytc(4)) with the Thr 146 and Phe 51 (of RCy). But the other Glu 121:His 143 associated complex (EH) of Cytc(4)-RCy was stabilized by the H-bonding interaction of the oxygen atoms O(epsilon1) and O(epsilon2) of Glu 121 with the Nepsilon and Ogamma atoms of His 143 and Thr 146 of RCy. The six water molecules were present in the binding region of the two proteins in the energy minimized autosolvated DH and EH-complexes. The MD studies also revealed the presence of six interacting water molecules at the binding region between the two proteins in both the complexes. Several residues Gly 82 and 84, His 143 (RCy) were participated through the water mediated (W 389, W 430, W 413, W 431, W 373, and W 478) interaction with the Asp 15, Ile 82, and 62, Tyr 63 (Cytc(4)) in DH complex, whereas in EH complex the Phe 51, Asn 80, Tyr 146 (RCy) residues were observed to interact with Asn 108, Met 120, Glu 121 (of Cytc(4)) through the water molecules W 507, W 445, W 401, W 446, and W 440. The direct water mediated (W 478) interaction of His 143 (RCy) to Asp 15 (of Cytc(4)) was observed only in the DH complex but not in EH. These direct and water mediated H-bonding between the two respective proteins and the binding free energy with higher interacting buried surface area of the DH complex compare to other EH complex have indicated an alternative possibility of the electron transfer route through the interaction of His 143 of RCy and the N-terminal Asp 15 of Cytc(4).
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Affiliation(s)
- B P Mukhopadhyay
- Department of Chemistry, National Institute Of Technology, Durgapur-713209, West Bengal, India.
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Magdesieva TV, Dolganov AV, Yakimanskii AV, Goikhman MY, Podeshvo IV, Kudryavtsev VV. Electrochemical synthesis of Cu-containing polyheteroarylenes and study of their catalytic properties. RUSS J ELECTROCHEM+ 2007. [DOI: 10.1134/s1023193507100059] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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de Jongh TE, Hoffmann M, Einsle O, Cavazzini D, Rossi G, Ubbink M, Canters GW. Inter‐ and Intramolecular Electron Transfer in Modified Azurin Dimers. Eur J Inorg Chem 2007. [DOI: 10.1002/ejic.200601234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Thyra E. de Jongh
- Leiden Institute of Chemistry, Leiden University, Gorlaeus Laboratories, P. O. Box 9502, 2300 RA Leiden, The Netherlands, Fax: +31‐71‐527‐4349, URL: http://www.chem.leidenuniv.nl/metprot
| | - Maren Hoffmann
- Institut für Mikrobiologie und Genetik, Georg‐August‐Universität Göttingen Justus‐von‐Liebig‐Weg 11, 37077 Göttingen, Germany
| | - Oliver Einsle
- Institut für Mikrobiologie und Genetik, Georg‐August‐Universität Göttingen Justus‐von‐Liebig‐Weg 11, 37077 Göttingen, Germany
| | - Davide Cavazzini
- Department of Biochemistry and Molecular Biology, University of Parma V.le G. P. Usberti 23/A., 43100 Parma, Italy
| | - Gian‐Luigi Rossi
- Department of Biochemistry and Molecular Biology, University of Parma V.le G. P. Usberti 23/A., 43100 Parma, Italy
| | - Marcellus Ubbink
- Leiden Institute of Chemistry, Leiden University, Gorlaeus Laboratories, P. O. Box 9502, 2300 RA Leiden, The Netherlands, Fax: +31‐71‐527‐4349, URL: http://www.chem.leidenuniv.nl/metprot
| | - Gerard W. Canters
- Leiden Institute of Chemistry, Leiden University, Gorlaeus Laboratories, P. O. Box 9502, 2300 RA Leiden, The Netherlands, Fax: +31‐71‐527‐4349, URL: http://www.chem.leidenuniv.nl/metprot
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McEvoy JP, Foord JS. Direct electrochemistry of blue copper proteins at boron-doped diamond electrodes. Electrochim Acta 2005. [DOI: 10.1016/j.electacta.2004.11.043] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Pinho D, Besson S, Brondino CD, Pereira E, de Castro B, Moura I. Two azurins with unusual redox and spectroscopic properties isolated from the Pseudomonas chlororaphis strains DSM 50083T and DSM 50135. J Inorg Biochem 2004; 98:276-86. [PMID: 14729308 DOI: 10.1016/j.jinorgbio.2003.10.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Two azurins (Az624 and Az626) were isolated from the soluble extract of two strains of Pseudomonas chlororaphis, DSM 50083(T) and DSM 50135, respectively, grown under microaerobic conditions with nitrate as final electron acceptor. The azurins, purified to electrophoretic homogeneity in three chromatographic steps, exhibit several peculiar properties. They have high reduction potentials and lower pI than most azurins described in the literature. As previously observed for Pseudomonas aeruginosa azurin, their reduction potentials are pH-dependent, but the pK values of their oxidized forms are lower, which suggests that deeper structural changes are associated with the oxidation process of these novel azurins. A hitherto undescribed pH-dependence of the diffusion coefficient was observed in Az624, that could be caused either by conformational changes, or by the formation of supramolecular aggregates associated with a protonation process. Both azurins exhibit axial X-band electron paramagnetic resonance spectra in frozen solution showing a typical hyperfine with the copper nucleus (I=3/2) and a well-resolved superhyperfine structure with two equivalent 14N nucleus (I=1), which is not usually observed for azurins from other species.
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Affiliation(s)
- Dora Pinho
- REQUIMTE, Departamento de Química, Faculdade de Ciências, Universidade do Porto, Porto 4169-007, Portugal
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18
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Electrochemical study of the intermolecular electron transfer to Pseudomonas aeruginosa cytochrome cd1 nitrite reductase. Electrochim Acta 2003. [DOI: 10.1016/s0013-4686(02)00843-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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19
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Jeuken LJ, Wisson LJ, Armstrong FA. The kinetics of a weakly electron-coupled proton transfer in azurin. Inorganica Chim Acta 2002. [DOI: 10.1016/s0020-1693(01)00809-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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20
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van Amsterdam IM, Ubbink M, Canters GW. Anti-cooperativity in the two electron oxidation of the S118C disulfide dimer of azurin. Inorganica Chim Acta 2002. [DOI: 10.1016/s0020-1693(02)00688-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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21
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Cutruzzolà F, Arese M, Ranghino G, van Pouderoyen G, Canters G, Brunori M. Pseudomonas aeruginosa cytochrome C(551): probing the role of the hydrophobic patch in electron transfer. J Inorg Biochem 2002; 88:353-61. [PMID: 11897350 DOI: 10.1016/s0162-0134(01)00390-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Cytochrome c(551) from Pseudomonas aeruginosa is a monomeric redox protein of 82 amino-acid residues, involved in dissimilative denitrification as the physiological electron donor of cd(1) nitrite reductase. The distribution of charged residues on the surface of c(551) is very anisotropic: one side is richer in acidic residues whereas the other shows a ring of positive side chains, mainly lysines, located at the border of an hydrophobic patch which surrounds the heme crevice. In order to map in cytochrome c(551) the surface involved in electron transfer, we have introduced specific mutations in three residues belonging to the hydrophobic patch, namely Val23-->Asp, Pro58-->Ala and Ile59-->Glu. The effect of these mutations was analyzed studying both the self-exchange rate and the electron-transfer activity towards P. aeruginosa cd(1) nitrite reductase, the physiological partner and P. aeruginosa azurin, a copper protein often used as a model redox partner in vitro. Our results show that introduction of a negative charge in the hydrophobic patch severely hampers both homonuclear and heteronuclear electron transfer.
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Affiliation(s)
- Francesca Cutruzzolà
- Dipartimento di Scienze Biochimiche, Università di Roma La Sapienza, P. le A. Moro 5, 00185 Rome, Italy.
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Martínez-Júlvez M, Nogués I, Faro M, Hurley JK, Brodie TB, Mayoral T, Sanz-Aparicio J, Hermoso JA, Stankovich MT, Medina M, Tollin G, Gómez-Moreno C. Role of a cluster of hydrophobic residues near the FAD cofactor in Anabaena PCC 7119 ferredoxin-NADP+ reductase for optimal complex formation and electron transfer to ferredoxin. J Biol Chem 2001; 276:27498-510. [PMID: 11342548 DOI: 10.1074/jbc.m102112200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the ferredoxin-NADP(+) reductase (FNR)/ferredoxin (Fd) system, an aromatic amino acid residue on the surface of Anabaena Fd, Phe-65, has been shown to be essential for the electron transfer (ET) reaction. We have investigated further the role of hydrophobic interactions in complex stabilization and ET between these proteins by replacing three hydrophobic residues, Leu-76, Leu-78, and Val-136, situated on the FNR surface in the vicinity of its FAD cofactor. Whereas neither the ability of FNR to accept electrons from NADPH nor its structure appears to be affected by the introduced mutations, different behaviors with Fd are observed. Thus, the ET interaction with Fd is almost completely lost upon introduction of negatively charged side chains. In contrast, only subtle changes are observed upon conservative replacement. Introduction of Ser residues produces relatively sizable alterations of the FAD redox potential, which can explain the modified behavior of these mutants. The introduction of bulky aromatic side chains appears to produce rearrangements of the side chains at the FNR/Fd interaction surface. Thus, subtle changes in the hydrophobic patch influence the rates of ET to and from Fd by altering the binding constants and the FAD redox potentials, indicating that these residues are especially important in the binding and orientation of Fd for efficient ET. These results are consistent with the structure reported for the Anabaena FNR.Fd complex.
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Affiliation(s)
- M Martínez-Júlvez
- Departamento de Bioquimica y Biologia Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, 50009-Zaragoza, Spain
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van Amsterdam IM, Ubbink M, Jeuken LJ, Verbeet MP, Einsle O, Messerschmidt A, Canters GW. Effects of dimerization on protein electron transfer. Chemistry 2001; 7:2398-406. [PMID: 11446642 DOI: 10.1002/1521-3765(20010601)7:11<2398::aid-chem23980>3.0.co;2-l] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In order to investigate the relationship between the rate of protein-protein electron transfer and the structure of the association complex, a dimer of the blue copper protein azurin was constructed and its electron exchange properties were determined. For this purpose, a site for covalent cross-linking was engineered by replacing the surface-exposed asparagine 42 with a cysteine. This mutation enabled the formation of disulfide-linked homo-dimers of azurin. Based on NMR line-broadening experiments, the electron self-exchange (e.s.e.) rate constant for this dimer was determined to be 4.2(+/-0.7) x 10(5)M(-1)s(-1), which is a seven-fold decrease relative to wild-type azurin. This difference is ascribed to a less accessible hydrophobic patch in the dimer. To discriminate between intramolecular electron transfer within a dimer and intermolecular electron transfer between two dimers, the e.s.e. rate constant of (Cu-Cu)-N42C dimers was compared with that of (Zn-Cu)- and (Ag-Cu)-N42C dimers. As Zn and Ag are redox inactive, the intramolecular electron transfer reaction in these latter dimers can be eliminated. The e.s.e. rate constants of the three dimers are the same and an upper limit for the intramolecular electron transfer rate of 10 s(-1) could be determined. This rate is compatible with a Cu-Cu distance of 18 A or more, which is larger than the Cu - Cu distance of 15 A observed in the wild-type crystal structure that shows two monomers that face each other with opposing hydrophobic patches. Modelling of the dimer shows that the Cu-Cu distance should be in the range of 17 A < rCu-Cu < 28 A, which is in agreement with the experimental findings. For efficient electron transfer, it appears crucial that the two molecules interact in the proper orientation. Direct cross-linking may disturb the formation of such an optimal electron transfer complex.
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De Rienzo F, Gabdoulline RR, Menziani MC, Wade RC. Blue copper proteins: a comparative analysis of their molecular interaction properties. Protein Sci 2000; 9:1439-54. [PMID: 10975566 PMCID: PMC2144732 DOI: 10.1110/ps.9.8.1439] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Blue copper proteins are type-I copper-containing redox proteins whose role is to shuttle electrons from an electron donor to an electron acceptor in bacteria and plants. A large amount of experimental data is available on blue copper proteins; however, their functional characterization is hindered by the complexity of redox processes in biological systems. We describe here the application of a semiquantitative method based on a comparative analysis of molecular interaction fields to gain insights into the recognition properties of blue copper proteins. Molecular electrostatic and hydrophobic potentials were computed and compared for a set of 33 experimentally-determined structures of proteins from seven blue copper subfamilies, and the results were quantified by means of similarity indices. The analysis provides a classification of the blue copper proteins and shows that (I) comparison of the molecular electrostatic potentials provides useful information complementary to that highlighted by sequence analysis; (2) similarities in recognition properties can be detected for proteins belonging to different subfamilies, such as amicyanins and pseudoazurins, that may be isofunctional proteins; (3) dissimilarities in interaction properties, consistent with experimentally different binding specificities, may be observed between proteins belonging to the same subfamily, such as cyanobacterial and eukaryotic plastocyanins; (4) proteins with low sequence identity, such as azurins and pseudoazurins, can have sufficient similarity to bind to similar electron donors and acceptors while having different binding specificity profiles.
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Affiliation(s)
- F De Rienzo
- European Molecular Biology Laboratory, Heidelberg, Germany
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25
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Kohzuma T, Inoue T, Yoshizaki F, Sasakawa Y, Onodera K, Nagatomo S, Kitagawa T, Uzawa S, Isobe Y, Sugimura Y, Gotowda M, Kai Y. The structure and unusual pH dependence of plastocyanin from the fern Dryopteris crassirhizoma. The protonation of an active site histidine is hindered by pi-pi interactions. J Biol Chem 1999; 274:11817-23. [PMID: 10206999 DOI: 10.1074/jbc.274.17.11817] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Spectroscopic properties, amino acid sequence, electron transfer kinetics, and crystal structures of the oxidized (at 1.7 A resolution) and reduced form (at 1.8 A resolution) of a novel plastocyanin from the fern Dryopteris crassirhizoma are presented. Kinetic studies show that the reduced form of Dryopteris plastocyanin remains redox-active at low pH, under conditions where the oxidation of the reduced form of other plastocyanins is inhibited by the protonation of a solvent-exposed active site residue, His87 (equivalent to His90 in Dryopteris plastocyanin). The x-ray crystal structure analysis of Dryopteris plastocyanin reveals pi-pi stacking between Phe12 and His90, suggesting that the active site is uniquely protected against inactivation. Like higher plant plastocyanins, Dryopteris plastocyanin has an acidic patch, but this patch is located closer to the solvent-exposed active site His residue, and the total number of acidic residues is smaller. In the reactions of Dryopteris plastocyanin with inorganic redox reagents, the acidic patch (the "remote" site) and the hydrophobic patch surrounding His90 (the "adjacent" site) are equally efficient for electron transfer. These results indicate the significance of the lack of protonation at the active site of Dryopteris plastocyanin, the equivalence of the two electron transfer sites in this protein, and a possibility of obtaining a novel insight into the photosynthetic electron transfer system of the first vascular plant fern, including its molecular evolutionary aspects. This is the first report on the characterization of plastocyanin and the first three-dimensional protein structure from fern plant.
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Affiliation(s)
- T Kohzuma
- Faculty of Science, Ibaraki University, Mito, Ibaraki 310-8512, Japan.
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26
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Dennison C, Kohzuma T. Alkaline Transition of Pseudoazurin from Achromobacter cycloclastes Studied by Paramagnetic NMR and Its Effect on Electron Transfer. Inorg Chem 1999. [DOI: 10.1021/ic981242r] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Christopher Dennison
- Department of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland, and Department of Chemistry, Ibaraki University, Mito, Ibaraki 310, Japan
| | - Takamitsu Kohzuma
- Department of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland, and Department of Chemistry, Ibaraki University, Mito, Ibaraki 310, Japan
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27
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28
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Dennison C, Canters G, Vries S, Vijgenboom E, Spanning R. The Methylamine Dehydrogenase Electron Transfer Chain. ADVANCES IN INORGANIC CHEMISTRY 1998. [DOI: 10.1016/s0898-8838(08)60029-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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29
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Abstract
Denitrification is a distinct means of energy conservation, making use of N oxides as terminal electron acceptors for cellular bioenergetics under anaerobic, microaerophilic, and occasionally aerobic conditions. The process is an essential branch of the global N cycle, reversing dinitrogen fixation, and is associated with chemolithotrophic, phototrophic, diazotrophic, or organotrophic metabolism but generally not with obligately anaerobic life. Discovered more than a century ago and believed to be exclusively a bacterial trait, denitrification has now been found in halophilic and hyperthermophilic archaea and in the mitochondria of fungi, raising evolutionarily intriguing vistas. Important advances in the biochemical characterization of denitrification and the underlying genetics have been achieved with Pseudomonas stutzeri, Pseudomonas aeruginosa, Paracoccus denitrificans, Ralstonia eutropha, and Rhodobacter sphaeroides. Pseudomonads represent one of the largest assemblies of the denitrifying bacteria within a single genus, favoring their use as model organisms. Around 50 genes are required within a single bacterium to encode the core structures of the denitrification apparatus. Much of the denitrification process of gram-negative bacteria has been found confined to the periplasm, whereas the topology and enzymology of the gram-positive bacteria are less well established. The activation and enzymatic transformation of N oxides is based on the redox chemistry of Fe, Cu, and Mo. Biochemical breakthroughs have included the X-ray structures of the two types of respiratory nitrite reductases and the isolation of the novel enzymes nitric oxide reductase and nitrous oxide reductase, as well as their structural characterization by indirect spectroscopic means. This revealed unexpected relationships among denitrification enzymes and respiratory oxygen reductases. Denitrification is intimately related to fundamental cellular processes that include primary and secondary transport, protein translocation, cytochrome c biogenesis, anaerobic gene regulation, metalloprotein assembly, and the biosynthesis of the cofactors molybdopterin and heme D1. An important class of regulators for the anaerobic expression of the denitrification apparatus are transcription factors of the greater FNR family. Nitrate and nitric oxide, in addition to being respiratory substrates, have been identified as signaling molecules for the induction of distinct N oxide-metabolizing enzymes.
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Affiliation(s)
- W G Zumft
- Lehrstuhl für Mikrobiologie, Universität Fridericiana, Karlsruhe, Germany
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30
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Van Pouderoyen G, Cigna G, Rolli G, Cutruzzolà F, Malatesta F, Silvestrini MC, Brunori M, Canters GW. Electron-transfer properties of Pseudomonas aeruginosa [Lys44, Glu64]azurin. EUROPEAN JOURNAL OF BIOCHEMISTRY 1997; 247:322-31. [PMID: 9249043 DOI: 10.1111/j.1432-1033.1997.00322.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In the hydrophobic patch of azurin from Pseudomonas aeruginosa, an electric dipole was created by changing Met44 into Lys and Met64 into Glu. The effect of this dipole on the electron-transfer properties of azurin was investigated. From a spectroscopic characterization (NMR, EPR and ultraviolet-visible) it was found that both the copper site and the overall structure of the [Lys44, Glu64]azurin were not disturbed by the two mutations. A small perturbation of the active site at high pH, similar to that observed for [Lys44]azurin, occurs in the double mutant. At neutral pH the electron-self-exchange rate constant of the double mutant shows a decrease of three orders of magnitude compared with the wild-type value. The possible reasons for this decrease are discussed. Electron transfer with the proposed physiological redox partners cytochrome c551 and nitrite reductase have been investigated and the data analyzed in the Marcus framework. From this analysis it is confirmed that the hydrophobic patch of azurin is the interaction site with both partners, and that cytochrome c551 uses its hydrophobic patch and nitrite reductase a negatively charged surface area for the electron transfer.
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Affiliation(s)
- G Van Pouderoyen
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, The Netherlands
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31
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Kukimoto M, Nishiyama M, Tanokura M, Murphy ME, Adman ET, Horinouchi S. Site-directed mutagenesis of azurin from Pseudomonas aeruginosa enhances the formation of an electron-transfer complex with a copper-containing nitrite reductase from Alcaligenes faecalis S-6. FEBS Lett 1996; 394:87-90. [PMID: 8925934 DOI: 10.1016/0014-5793(96)00934-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Kinetic analysis of electron transfer between azurin from Pseudomonas aeruginosa and copper-containing nitrite reductase (NIR) from Akaligenes faecalis S-6 was carried out to investigate the specificity of electron transfer between copper-containing proteins. Apparent values of kcat and Km of NIR for azurin were 300-fold smaller and 172-fold larger than those for the physiological redox partner, pseudoazurin from A. faecalis S-6, respectively, suggesting that the electron transfer between azurin and NIR was less specific than that between pseudoazurin and NIR. One of the major differences in 3-D structure between these redox proteins, azurin and pseudoazurin, is the absence and presence of lysine residues near their type 1 copper sites, respectively. Three mutated azurins, D11K, P36K, and D11K/P36K, were constructed to evaluate the importance of lysine residues in the interaction with NIR. The redox potentials of D11K, P36K, and D11K/P36K azurins were higher than that of wild-type azurin by 48, 7, and 55 mV, respectively. As suggested by the increase in the redox potential, kinetic analysis of electron transfer revealed reduced ability of electron transfer in the mutated azurins. On the other hand, although each of the single mutations caused modest effects on the decrease in the Km value, the simultaneous mutations of D11K and P36K caused significant decrease in the Km value when compared to that for wild-type azurin. These results suggest that the introduction of two lysine residues into azurin facilitated docking to NIR.
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Affiliation(s)
- M Kukimoto
- Department of Biotechnology, The University of Tokyo, Japan
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32
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McMaster J, Beddoes RL, Collison D, Eardley DR, Helliwell M, Garner CD. A bis(diimidazole)Copper Complex Possessing a Reversible CuII/CuI Couple with a High Redox Potential. Chemistry 1996. [DOI: 10.1002/chem.19960020613] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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33
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Structure-function correlation of intramolecular electron transfer in wild type and single-site mutated azurins. Chem Phys 1996. [DOI: 10.1016/0301-0104(95)00294-4] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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34
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Dennison C, Van Driessche G, Van Beeumen J, McFarlane W, Geoffrey Sykes A. Electron-Transfer Properties and Active-Site Structure of the Type 1 (Blue) Copper Protein Umecyanin. Chemistry 1996. [DOI: 10.1002/chem.19960020118] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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35
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Larsson S, Källebring B, Wittung P, Malmström BG. The CuA center of cytochrome-c oxidase: electronic structure and spectra of models compared to the properties of CuA domains. Proc Natl Acad Sci U S A 1995; 92:7167-71. [PMID: 7638162 PMCID: PMC41300 DOI: 10.1073/pnas.92.16.7167] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The electronic structure and spectrum of several models of the binuclear metal site in soluble CuA domains of cytochrome-c oxidase have been calculated by the use of an extended version of the complete neglect of differential overlap/spectroscopic method. The experimental spectra have two strong transitions of nearly equal intensity around 500 nm and a near-IR transition close to 800 nm. The model that best reproduces these features consists of a dimer of two blue (type 1) copper centers, in which each Cu atom replaces the missing imidazole on the other Cu atom. Thus, both Cu atoms have one cysteine sulfur atom and one imidazole nitrogen atom as ligands, and there are no bridging ligands but a direct Cu-Cu bond. According to the calculations, the two strong bands in the visible region originate from exciton coupling of the dipoles of the two copper monomers, and the near-IR band is a charge-transfer transition between the two Cu atoms. The known amino acid sequence has been used to construct a molecular model of the CuA site by the use of a template and energy minimization. In this model, the two ligand cysteine residues are in one turn of an alpha-helix, whereas one ligand histidine is in a loop following this helix and the other one is in a beta-strand.
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Affiliation(s)
- S Larsson
- Department of Physical Chemistry University of Technology, Göteborg, Sweden
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36
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Salgado J, Jiménez HR, Donaire A, Moratal JM. 1H-NMR study of a cobalt-substituted blue copper protein: Pseudomonas aeruginosa Co(II)-azurin. EUROPEAN JOURNAL OF BIOCHEMISTRY 1995; 231:358-69. [PMID: 7635147 DOI: 10.1111/j.1432-1033.1995.tb20708.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Substitution of copper by cobalt in blue copper proteins gives a paramagnetic metalloderivative suitable for paramagnetic NMR studies. A thorough analysis of the 1H-NMR spectrum of Pseudomonas aeruginosa Co(II)-azurin is presented here. All the observable contact-shifted signals as well as many other paramagnetic signals from protons placed up to about 1.0 nm around the metal center, including some residues belonging to functionally important parts of the protein like the hydrophobic patch and the His35 region, have been assigned. The results obtained permit the detection and study of structural variations like those originated by the His35 ionization, and allow us to draw a feasible picture of the metal coordination site. Contact-shifted signals correspond to the same five residues which are found in the coordination sphere of the native Cu(II)-azurin, i.e. His46, His117, Cys112, Met121 and Gly45. Among them, the histidine residues present a pattern of resonances typical for histidines coordinated to cobalt in other cobalt protein derivatives, and the cysteine signals clearly indicate a strong interaction with the paramagnetic Co(II) ion. In contrast, the Met121 signals indicate a weak but still existent contact interaction with the metal center. On the other hand, the very weak copper ligand, Gly45, appears here as clearly coordinated to cobalt. Results are consistent with a distorted tetrahedral metal site with the cobalt deviated from the N2S plane towards the Gly45 O axial position and weakly interacting with the Met121 sulfur.
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Affiliation(s)
- J Salgado
- Department of Inorganic Chemistry, University of Valencia, Burjassot, Spain
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