1
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Szuster J, Zitare UA, Castro MA, Leguto AJ, Morgada MN, Vila AJ, Murgida DH. Cu A-based chimeric T1 copper sites allow for independent modulation of reorganization energy and reduction potential. Chem Sci 2020; 11:6193-6201. [PMID: 32953013 PMCID: PMC7480511 DOI: 10.1039/d0sc01620a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 06/01/2020] [Indexed: 01/19/2023] Open
Abstract
Attaining rational modulation of thermodynamic and kinetic redox parameters of metalloproteins is a key milestone towards the (re)design of proteins with new or improved redox functions. Here we report that implantation of ligand loops from natural T1 proteins into the scaffold of a CuA protein leads to a series of distorted T1-like sites that allow for independent modulation of reduction potentials (E°') and electron transfer reorganization energies (λ). On the one hand E°' values could be fine-tuned over 120 mV without affecting λ. On the other, λ values could be modulated by more than a factor of two while affecting E°' only by a few millivolts. These results are in sharp contrast to previous studies that used T1 cupredoxin folds, thus highlighting the importance of the protein scaffold in determining such parameters.
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Affiliation(s)
- Jonathan Szuster
- Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE, CONICET-UBA) , Argentina .
- Departamento de Química Inorgánica, Analítica y Química-Física , Facultad de Ciencias Exactas y Naturales , Universidad de Buenos Aires , Buenos Aires , Argentina
| | - Ulises A Zitare
- Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE, CONICET-UBA) , Argentina .
- Departamento de Química Inorgánica, Analítica y Química-Física , Facultad de Ciencias Exactas y Naturales , Universidad de Buenos Aires , Buenos Aires , Argentina
| | - María A Castro
- Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE, CONICET-UBA) , Argentina .
- Departamento de Química Inorgánica, Analítica y Química-Física , Facultad de Ciencias Exactas y Naturales , Universidad de Buenos Aires , Buenos Aires , Argentina
| | - Alcides J Leguto
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR) , Argentina
- Departamento de Química Biológica , Facultad de Ciencias Bioquímicas y Farmacéuticas , Universidad Nacional de Rosario , Rosario , Argentina
| | - Marcos N Morgada
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR) , Argentina
- Departamento de Química Biológica , Facultad de Ciencias Bioquímicas y Farmacéuticas , Universidad Nacional de Rosario , Rosario , Argentina
| | - Alejandro J Vila
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR) , Argentina
- Departamento de Química Biológica , Facultad de Ciencias Bioquímicas y Farmacéuticas , Universidad Nacional de Rosario , Rosario , Argentina
| | - Daniel H Murgida
- Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE, CONICET-UBA) , Argentina .
- Departamento de Química Inorgánica, Analítica y Química-Física , Facultad de Ciencias Exactas y Naturales , Universidad de Buenos Aires , Buenos Aires , Argentina
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2
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Chen H, Su B, Zhang T, Huang A, Liu H, Yu Y, Wang J. Engineering the metal-binding loop at a type 1 copper center by circular permutation. RSC Adv 2017. [DOI: 10.1039/c7ra11512a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Circular permutation of the cupredoxin azurin creates a break on the metal binding loop, highlighting the loop's flexibility.
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Affiliation(s)
- Honghui Chen
- College of Biotechnology
- Tianjin University of Science and Technology
- Tianjin
- China
- Tianjin Institute of Industrial Biotechnology
| | - Binbin Su
- College of Biotechnology
- Tianjin University of Science and Technology
- Tianjin
- China
- Tianjin Institute of Industrial Biotechnology
| | - Tongtong Zhang
- Tianjin Institute of Industrial Biotechnology
- Chinese Academy of Sciences
- Tianjin
- China
| | - Aiping Huang
- Tianjin Institute of Industrial Biotechnology
- Chinese Academy of Sciences
- Tianjin
- China
| | - Haiping Liu
- Tianjin Institute of Industrial Biotechnology
- Chinese Academy of Sciences
- Tianjin
- China
| | - Yang Yu
- Tianjin Institute of Industrial Biotechnology
- Chinese Academy of Sciences
- Tianjin
- China
| | - Jiangyun Wang
- Laboratory of RNA Biology
- Institute of Biophysics
- Chinese Academy of Sciences
- Beijing
- China
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3
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Le Sueur AL, Schaugaard RN, Baik MH, Thielges MC. Methionine Ligand Interaction in a Blue Copper Protein Characterized by Site-Selective Infrared Spectroscopy. J Am Chem Soc 2016; 138:7187-93. [PMID: 27164303 DOI: 10.1021/jacs.6b03916] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The reactivity of metal sites in proteins is tuned by protein-based ligands. For example, in blue copper proteins such as plastocyanin (Pc), the structure imparts a highly elongated bond between the Cu and a methionine (Met) axial ligand to modulate its redox properties. Despite extensive study, a complete understanding of the contribution of the protein to redox activity is challenged by experimentally accessing both redox states of metalloproteins. Using infrared (IR) spectroscopy in combination with site-selective labeling with carbon-deuterium (C-D) vibrational probes, we characterized the localized changes at the Cu ligand Met97 in the oxidized and reduced states, as well as the Zn(II) or Co(II)-substituted, the pH-induced low-coordinate, the apoprotein, and the unfolded states. The IR absorptions of (d3-methyl)Met97 are highly sensitive to interaction of the sulfur-based orbitals with the metal center and are demonstrated to be useful reporters of its modulation in the different states. Unrestricted Kohn-Sham density functional theory calculations performed on a model of the Cu site of Pc confirm the observed dependence. IR spectroscopy was then applied to characterize the impact of binding to the physiological redox partner cytochrome (cyt) f. The spectral changes suggest a slightly stronger Cu-S(Met97) interaction in the complex with cyt f that has potential to modulate the electron transfer properties. Besides providing direct, molecular-level comparison of the oxidized and reduced states of Pc from the perspective of the axial Met ligand and evidence for perturbation of the Cu site properties by redox partner binding, this study demonstrates the localized spatial information afforded by IR spectroscopy of selectively incorporated C-D probes.
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Affiliation(s)
- Amanda L Le Sueur
- Department of Chemistry, Indiana University , 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Richard N Schaugaard
- Department of Chemistry, Indiana University , 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Mu-Hyun Baik
- Department of Chemistry, Indiana University , 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Megan C Thielges
- Department of Chemistry, Indiana University , 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
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4
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Roger M, Biaso F, Castelle CJ, Bauzan M, Chaspoul F, Lojou E, Sciara G, Caffarri S, Giudici-Orticoni MT, Ilbert M. Spectroscopic characterization of a green copper site in a single-domain cupredoxin. PLoS One 2014; 9:e98941. [PMID: 24932914 PMCID: PMC4059628 DOI: 10.1371/journal.pone.0098941] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 05/09/2014] [Indexed: 12/13/2022] Open
Abstract
Cupredoxins are widespread copper-binding proteins, mainly involved in electron transfer pathways. They display a typical rigid greek key motif consisting of an eight stranded β-sandwich. A fascinating feature of cupredoxins is the natural diversity of their copper center geometry. These geometry variations give rise to drastic changes in their color, such as blue, green, red or purple. Based on several spectroscopic and structural analyses, a connection between the geometry of their copper-binding site and their color has been proposed. However, little is known about the relationship between such diversity of copper center geometry in cupredoxins and possible implications for function. This has been difficult to assess, as only a few naturally occurring green and red copper sites have been described so far. We report herein the spectrocopic characterization of a novel kind of single domain cupredoxin of green color, involved in a respiratory pathway of the acidophilic organism Acidithiobacillus ferrooxidans. Biochemical and spectroscopic characterization coupled to bioinformatics analysis reveal the existence of some unusual features for this novel member of the green cupredoxin sub-family. This protein has the highest redox potential reported to date for a green-type cupredoxin. It has a constrained green copper site insensitive to pH or temperature variations. It is a green-type cupredoxin found for the first time in a respiratory pathway. These unique properties might be explained by a region of unknown function never found in other cupredoxins, and by an unusual length of the loop between the second and the fourth copper ligands. These discoveries will impact our knowledge on non-engineered green copper sites, whose involvement in respiratory chains seems more widespread than initially thought.
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Affiliation(s)
- Magali Roger
- Unité de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, CNRS-UMR7281, Aix-Marseille Université, Marseille, France
| | - Frédéric Biaso
- Unité de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, CNRS-UMR7281, Aix-Marseille Université, Marseille, France
| | - Cindy J. Castelle
- Department of Earth and Planetary Science, University of California, Berkeley, California, United States of America
| | - Marielle Bauzan
- Unité de Fermentation, Institut de Microbiologie de la Méditerranée, CNRS-FR 3479, Aix Marseille Université, Marseille, France
| | - Florence Chaspoul
- Unité Chimie Physique, Prévention des Risques et Nuisances Technologiques, Faculté de Pharmacie, CNRS-UMR 7263, Aix-Marseille Université, Marseille, France
| | - Elisabeth Lojou
- Unité de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, CNRS-UMR7281, Aix-Marseille Université, Marseille, France
| | - Giuliano Sciara
- Unité de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, CNRS-UMR7281, Aix-Marseille Université, Marseille, France
| | - Stefano Caffarri
- Unité de Biologie Végétale et Microbiologie Environnementales, CNRS-UMR 7265, CEA, Aix Marseille Université, Marseille, France
| | - Marie-Thérèse Giudici-Orticoni
- Unité de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, CNRS-UMR7281, Aix-Marseille Université, Marseille, France
| | - Marianne Ilbert
- Unité de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, CNRS-UMR7281, Aix-Marseille Université, Marseille, France
- * E-mail:
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5
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Morgada MN, Abriata LA, Zitare U, Alvarez-Paggi D, Murgida DH, Vila AJ. Control of the Electronic Ground State on an Electron-Transfer Copper Site by Second-Sphere Perturbations. Angew Chem Int Ed Engl 2014; 53:6188-92. [DOI: 10.1002/anie.201402083] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 02/24/2014] [Indexed: 01/07/2023]
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6
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Morgada MN, Abriata LA, Zitare U, Alvarez-Paggi D, Murgida DH, Vila AJ. Control of the Electronic Ground State on an Electron-Transfer Copper Site by Second-Sphere Perturbations. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201402083] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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7
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Allen S, Badarau A, Dennison C. The influence of protein folding on the copper affinities of trafficking and target sites. Dalton Trans 2012; 42:3233-9. [PMID: 23169585 DOI: 10.1039/c2dt32166a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The relative influence of protein unfolding on the Cu(I) affinity of trafficking and target sites for copper has been determined. For the copper metallochaperone Atx1 from Synechocystis PCC 6803 (a cyanobacterium), Saccharomyces cerevisiae and humans unfolding in urea results in a decrease in the Cu(I) affinity from (4-5) × 10(17) M(-1) to (1-3) × 10(16) M(-1) at pH 7. The affinities of the unfolded Atx1s are similar to those for CXXC-containing peptides. Partial unfolding, due to the loop 5 His61Lys mutation in Synechocystis Atx1, gives rise to a more limited decrease in Cu(I) affinity. For the copper target protein plastocyanin from Synechocystis, chemical unfolding results in the Cu(I) affinity decreasing by 5-orders of magnitude. This differential influence of protein unfolding on Cu(I) affinity is due to a more complex copper site structure in the target protein, including numerous interactions of non-coordinating residues with ligating amino acids. This second-coordination sphere is much simpler in the Atx1s with the main interaction provided by the loop 5 residue that tunes the Cu(I) affinity by altering the pK(a) of the C-terminal Cys ligand of the CXXC motif. This interaction and others are absent in the unfolded Atx1s and the two Cys ligands have pK(a) values reminiscent of free thiols (>8) resulting in lowered Cu(I) affinities at pH 7. Residues close to the active site of the thiol-disulfide oxidoreductase thioredoxin appear to lower the Cu(I) affinity of its CXXC motif to 3.1 × 10(15) M(-1) at pH 7, presumably to prevent copper binding in vivo. The structure of a copper site, including the number and relative position of ligands in the primary structure and the complexity of the second-coordination sphere, results in dramatically different effects of unfolding on Cu(I) affinity that has important implications for copper homeostasis.
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Affiliation(s)
- Stephen Allen
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
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8
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Laming EM, McGrath AP, Guss JM, Kappler U, Maher MJ. The X-ray crystal structure of a pseudoazurin from Sinorhizobium meliloti. J Inorg Biochem 2012; 115:148-54. [DOI: 10.1016/j.jinorgbio.2012.04.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 04/20/2012] [Accepted: 04/20/2012] [Indexed: 10/28/2022]
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9
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Incorporation of the red copper nitrosocyanin binding loop into blue copper azurin. J Biol Inorg Chem 2010; 16:473-80. [DOI: 10.1007/s00775-010-0746-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Accepted: 11/24/2010] [Indexed: 10/18/2022]
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10
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Najmudin S, Pauleta SR, Moura I, Romão MJ. The 1.4 A resolution structure of Paracoccus pantotrophus pseudoazurin. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:627-35. [PMID: 20516588 PMCID: PMC2882758 DOI: 10.1107/s1744309110013989] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2010] [Accepted: 04/15/2010] [Indexed: 11/10/2022]
Abstract
Pseudoazurins are small type 1 copper proteins that are involved in the flow of electrons between various electron donors and acceptors in the bacterial periplasm, mostly under denitrifying conditions. The previously determined structure of Paracoccus pantotrophus pseudoazurin in the oxidized form was improved to a nominal resolution of 1.4 A, with R and R(free) values of 0.188 and 0.206, respectively. This high-resolution structure makes it possible to analyze the interactions between the monomers and the solvent structure in detail. Analysis of the high-resolution structure revealed the structural regions that are responsible for monomer-monomer recognition during dimer formation and for protein-protein interaction and that are important for partner recognition. The pseudoazurin structure was compared with other structures of various type 1 copper proteins and these were grouped into families according to similarities in their secondary structure; this may be useful in the annotation of copper proteins in newly sequenced genomes and in the identification of novel copper proteins.
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Affiliation(s)
- Shabir Najmudin
- REQUIMTE, Centro de Química Fina e Biotecnologia, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Sofia R. Pauleta
- REQUIMTE, Centro de Química Fina e Biotecnologia, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Isabel Moura
- REQUIMTE, Centro de Química Fina e Biotecnologia, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Maria J. Romão
- REQUIMTE, Centro de Química Fina e Biotecnologia, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
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11
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Savelieff MG, Lu Y. CuA centers and their biosynthetic models in azurin. J Biol Inorg Chem 2010; 15:461-83. [DOI: 10.1007/s00775-010-0625-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2009] [Accepted: 01/20/2010] [Indexed: 11/28/2022]
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12
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Worrall JAR, Vijgenboom E. Copper mining in Streptomyces: enzymes, natural products and development. Nat Prod Rep 2010; 27:742-56. [DOI: 10.1039/b804465c] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Shimazaki Y, Takani M, Yamauchi O. Metal complexes of amino acids and amino acid side chain groups. Structures and properties. Dalton Trans 2009:7854-69. [PMID: 19771344 DOI: 10.1039/b905871k] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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14
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Sato K, Firbank S, Li C, Banfield M, Dennison C. The Importance of the Long Type 1 Copper‐Binding Loop of Nitrite Reductase for Structure and Function. Chemistry 2008; 14:5820-8. [DOI: 10.1002/chem.200701997] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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15
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Experimental evidence for a link among cupredoxins: red, blue, and purple copper transformations in nitrous oxide reductase. Proc Natl Acad Sci U S A 2008; 105:7919-24. [PMID: 18535143 DOI: 10.1073/pnas.0711316105] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The cupredoxin fold is an important motif in numerous proteins that are central to several critical cellular processes ranging from aerobic and anaerobic respiration to catalysis and iron homeostasis. Three types of copper sites have been found to date within cupredoxin folds: blue type 1 (T1) copper, red type 2 (T2) copper, and purple Cu(A). Although as much as 90% sequence difference has been observed among some members of this superfamily of proteins that span several kingdoms, sequence alignment and phylogenic trees strongly suggest an evolutionary link and common ancestry. However, experimental evidence for such a link has been lacking. We report herein the observation of pH-dependent transformation between blue T1 copper, red T2 copper, and the native purple Cu(A) centers of nitrous oxide reductase (N2OR) from Paracoccus denitrificans. The blue and red copper centers form initially before they are transformed into purple Cu(A) center. This transformation process is pH-dependent, with lower pH resulting in fewer trapped T1 and T2 coppers and faster transition to purple Cu(A). These observations suggest that the purple Cu(A) site contains the essential elements of T1 and T2 copper centers and that the Cu(A) center is preferentially formed at low pH. Therefore, this work provides an underlying link between the various cupredoxin copper sites and possible experimental evidence in vitro for the evolutionary relationship between the cupredoxin proteins. The findings also lend physiological relevance to cupredoxin site biosynthesis.
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16
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Yamauchi O, Yajima T, Fujii R, Shimazaki Y, Yabusaki M, Takani M, Tashiro M, Motoyama T, Kakuto M, Nakabayashi Y. CH⋯Metal(II) axial interaction in planar complexes (metal=Cu, Pd) and implications for possible environmental effects of alkyl groups at biological copper sites. J Inorg Biochem 2008; 102:1218-26. [DOI: 10.1016/j.jinorgbio.2007.11.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2007] [Revised: 10/15/2007] [Accepted: 11/30/2007] [Indexed: 11/29/2022]
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17
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Abstract
Many approaches are being used to engineer metalloproteins, with most of these informed by, and aiming to further elucidate, the basic structural requirements for biological metal centers. Cupredoxins are type 1 (T1) copper-containing electron transfer (ET) proteins with a -barrel fold that is thought to constrain metal site structure. The T1 copper ion is bound by ligands mainly originating from a single active site loop whose length and structure varies. This Highlight article will focus on protein engineering studies which have investigated the role of the metal-binding loop for active site integrity and functionality. Scaffold differences are present within the cupredoxin family and their influence has also been assessed. Given the widespread occurrence of -barrel domains in nature, and the array of metal sites in proteins composed of loop regions, the studies described on this model system have implications for a variety of metalloproteins.
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Affiliation(s)
- Christopher Dennison
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne, UK.
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18
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Li C, Yanagisawa S, Martins BM, Messerschmidt A, Banfield MJ, Dennison C. Basic requirements for a metal-binding site in a protein: the influence of loop shortening on the cupredoxin azurin. Proc Natl Acad Sci U S A 2006; 103:7258-63. [PMID: 16651527 PMCID: PMC1464330 DOI: 10.1073/pnas.0600774103] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2006] [Indexed: 11/18/2022] Open
Abstract
The main active-site loop of the copper-binding protein azurin (a cupredoxin) has been shortened from C(112)TFPGH(117)SALM(121) to C(112)TPH(115)PFM(118) (the native loop from the cupredoxin amicyanin) and also to C(112)TPH(115)PM(117). The Cu(II) site structure is almost unaffected by shortening, as is that of the Cu(I) center at alkaline pH in the variant with the C(112)TPH(115)PM(117) loop sequence. Subtle spectroscopic differences due to alterations in the spin density distribution at the Cu(II) site can be attributed mainly to changes in the hydrogen-bonding pattern. Electron transfer is almost unaffected by the introduction of the C(112)TPH(115)PFM(118) loop, but removal of the Phe residue has a sizable effect on reactivity, probably because of diminished homodimer formation. At mildly acidic pH values, the His-115 ligand protonates and dissociates from the cuprous ion, an effect that has a dramatic influence on the reactivity of cupredoxins. These studies demonstrate that the amicyanin loop adopts a conformation identical to that found in the native protein when introduced into azurin, that a shorter than naturally occurring C-terminal active-site loop can support a functional T1 copper site, that CTPHPM is the minimal loop length required for binding this ubiquitous electron transfer center, and that the length and sequence of a metal-binding loop regulates a range of structural and functional features of the active site of a metalloprotein.
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Affiliation(s)
- Chan Li
- Institute for Cell and Molecular Biosciences, Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Sachiko Yanagisawa
- Institute for Cell and Molecular Biosciences, Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Berta M. Martins
- Elitenetzwerk Bayern Macromolecular Science, Mikrobiologie/Proteinkristallographie Laboratories, Universität Bayreuth, D-95440 Bayreuth, Germany; and
| | - Albrecht Messerschmidt
- Max-Planck-Institut für Biochemie, Abteilung Strukturforschung, Am Klopferspitz 18, D-82152 Martinsried, Germany
| | - Mark J. Banfield
- Institute for Cell and Molecular Biosciences, Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Christopher Dennison
- Institute for Cell and Molecular Biosciences, Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4HH, United Kingdom
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19
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Tolman WB. Using synthetic chemistry to understand copper protein active sites: a personal perspective. J Biol Inorg Chem 2006; 11:261-71. [PMID: 16447049 DOI: 10.1007/s00775-006-0078-9] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2005] [Accepted: 01/03/2006] [Indexed: 10/25/2022]
Abstract
The results of studies performed in the author's laboratory are surveyed, with particular emphasis on demonstrating the value of a multidisciplinary synthetic modeling approach for discovering new and unusual chemistry helpful for understanding the properties of the active sites of copper proteins or assessing the feasibility of mechanistic pathways they might follow during catalysis. The discussion focuses on the progress made to date toward comprehending the nitrite reductase catalytic site and mechanism, the electronic structures of copper thiolate electron transfer centers, the sulfido-bridged "CuZ" site in nitrous oxide reductase, and the processes of dioxygen binding and activation by mono- and dicopper centers in oxidases and oxygenases.
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Affiliation(s)
- William B Tolman
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant Street SE, Minneapolis, MN 55455, USA.
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20
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Garner D, McMaster J, Raven E, Walton P. Dalton Discussion No. 8. Metals: centres of biological activity. Dalton Trans 2005:3372-4. [PMID: 16234913 DOI: 10.1039/b513314a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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