1
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Wei Y, Li P. Theoretical insights into the reduction of Azurin metal site with unnatural amino acid substitutions. J Inorg Biochem 2024; 259:112651. [PMID: 38968926 DOI: 10.1016/j.jinorgbio.2024.112651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 06/10/2024] [Accepted: 06/21/2024] [Indexed: 07/07/2024]
Abstract
Copper-containing proteins play crucial roles in biological systems. Azurin is a copper-containing protein which has a Type 1 copper site that facilitates electron transfer in the cytochrome chain. Previous research has highlighted the significant impact of mutations in the axial Met121 of the copper site on the reduction potential. However, the mechanism of this regulation has not been fully established. In this study, we employed theoretical modeling to investigate the reduction of the Type 1 copper site, focusing on how unnatural amino acid substitutions at Met121 influence its behavior. Our findings demonstrated a strong linear correlation between electrostatic interactions and the reduction potential of the copper site, which indicates that the perturbation of the reduction potential is primarily influenced by electrostatic interactions between the metal ion and the ligating atom. Furthermore, we found that CF/π and CF…H interactions could induce subtle changes in geometry and hence impact the electronic properties of the systems under study. In addition, our calculations suggest the coordination mode and ion-ligand distance could significantly impact the reduction potential of a copper site. Overall, this study offers valuable insights into the structural and electronic properties of the Type 1 copper site, which could potentially guide the design of future artificial catalysts.
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Affiliation(s)
- Yang Wei
- Department of Chemistry and Biochemistry, Loyola University Chicago, Chicago, IL 60660, United States
| | - Pengfei Li
- Department of Chemistry and Biochemistry, Loyola University Chicago, Chicago, IL 60660, United States.
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2
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Mitra S, Ainavarapu SRK, Dasgupta J. Long-Range Charge Delocalization Mediates the Ultrafast Ligand-to-Metal Charge Transfer Dynamics at the Cu 2+-Active Site in Azurin. J Phys Chem B 2022; 126:5390-5399. [PMID: 35797135 DOI: 10.1021/acs.jpcb.2c01427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The blue color metalloprotein in azurin has traditionally been attributed to the intense cysteine-to-Cu2+ ligand-to-metal charge transfer transition centered at 628 nm. Although resonance Raman measurements of the Cu2+ active site have implied that the LMCT transition electronically couples to the protein scaffold well beyond its primary metal-ligand coordination shell, the structural extent of this electronic coupling and visualization of the protein-mediated charge transfer dynamics have remained elusive. Here, using femtosecond broadband transient absorption and impulsive Raman spectroscopy, we provide direct evidence for a rapid relaxation between two distinct charge transfer states, having different spatial delocalization, within ∼300 fs followed by recombination of charges in subpicosecond time scales. We invoke the formation of a protein-centered radical cation, possibly Trp48 or a Phe residue, within 100 fs substantiating the long-range electronic coupling for the first time beyond the traditional copper active site. The Raman spectra of the excited CT state show the presence of protein-centric vibrations along with the vibrational modes assigned to the copper active site. Our results demonstrate a large delocalization length scale of the initially populated CT state, thereby highlighting the possibility of exploiting azurin photochemistry for energy conversion techniques.
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Affiliation(s)
- Soumyajit Mitra
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
| | | | - Jyotishman Dasgupta
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
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3
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Schulz C, van Gastel M, Pantazis DA, Neese F. Converged Structural and Spectroscopic Properties for Refined QM/MM Models of Azurin. Inorg Chem 2021; 60:7399-7412. [PMID: 33939922 PMCID: PMC8154437 DOI: 10.1021/acs.inorgchem.1c00640] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Indexed: 12/27/2022]
Abstract
Blue copper proteins continue to challenge experiment and theory with their electronic structure and spectroscopic properties that respond sensitively to the coordination environment of the copper ion. In this work, we report state-of-the art electronic structure studies for geometric and spectroscopic properties of the archetypal "Type I" copper protein azurin in its Cu(II) state. A hybrid quantum mechanics/molecular mechanics (QM/MM) approach is used, employing both density functional theory (DFT) and coupled cluster with singles, doubles, and perturbative triples (CCSD(T)) methods for the QM region, the latter method making use of the domain-based local pair natural orbital (DLPNO) approach. Models of increasing QM size are employed to investigate the convergence of critical geometric parameters. It is shown that convergence is slow and that a large QM region is critical for reproducing the short experimental Cu-SCys112 distance. The study of structural convergence is followed by investigation of spectroscopic parameters using both DFT and DLPNO-CC methods and comparing these to the experimental spectrum using simulations. The results allow us to examine for the first time the distribution of spin densities and hyperfine coupling constants at the coupled cluster level, leading us to revisit the experimental assignment of the 33S hyperfine splitting. The wavefunction-based approach to obtain spin-dependent properties of open-shell systems demonstrated here for the case of azurin is transferable and applicable to a large array of bioinorganic systems.
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Affiliation(s)
- Christine
E. Schulz
- Max-Planck-Institut für
Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Maurice van Gastel
- Max-Planck-Institut für
Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Dimitrios A. Pantazis
- Max-Planck-Institut für
Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Frank Neese
- Max-Planck-Institut für
Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
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4
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First-principles study on the structure and optical spectroscopy of the redox-active center of blue copper proteins. Chem Phys 2020. [DOI: 10.1016/j.chemphys.2020.110859] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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5
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Yu SS, Li JJ, Cui C, Tian S, Chen JJ, Yu HQ, Hou C, Nilges MJ, Lu Y. Structural Basis for a Quadratic Relationship between Electronic Absorption and Electronic Paramagnetic Resonance Parameters of Type 1 Copper Proteins. Inorg Chem 2020; 59:10620-10627. [PMID: 32689800 DOI: 10.1021/acs.inorgchem.0c01065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Type 1 copper (T1Cu) proteins play important roles in electron transfer in biology, largely due to the unique structure of the T1Cu center, which is reflected by its spectroscopic properties. Previous reports have suggested a correlation between a high ratio of electronic absorbance at ∼450 nm to that at ∼600 nm (R = A450/A600) and a large copper(II) hyperfine coupling in the z direction (Az) in electron paramagnetic resonance (EPR). However, this correlation does not have a clear physical meaning, nor does it hold for many proteins with a perturbed T1Cu center. To address this issue, a new parameter of R' [A450/(A450 + A600)] with a better physical meaning of a fractional SCys pseudo-σ to Cu(II) charge transfer transition intensity is defined and a quadratic relationship between R' and Az is found on the basis of a comprehensive analysis of ultraviolet-visible absorption, EPR, and structural parameters of T1Cu proteins. We are able to find good correlations between R' and the displacement of copper from the trigonal plane defined by the His2Cys ligands and the angle between the NHis1-Cu-NHis2 plane and the SCys-Cu-axial ligand plane, providing a structural basis for the observed correlation. These findings and analyses provide a new framework for a deeper understanding of the spectroscopic and electronic properties of T1Cu proteins, which may allow better design and applications of this important class of proteins for redox and electron transfer functions.
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Affiliation(s)
- Sheng-Song Yu
- Department of Applied Chemistry, University of Science & Technology of China, Hefei, Anhui 230026, P. R. China.,Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Jun-Jie Li
- Key Laboratory of Biorheology Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044, P. R. China.,Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Chang Cui
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Shiliang Tian
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Jie-Jie Chen
- Department of Applied Chemistry, University of Science & Technology of China, Hefei, Anhui 230026, P. R. China
| | - Han-Qing Yu
- Department of Applied Chemistry, University of Science & Technology of China, Hefei, Anhui 230026, P. R. China
| | - Changjun Hou
- Key Laboratory of Biorheology Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044, P. R. China
| | - Mark J Nilges
- School of Chemical Sciences Electron Paramagnetic Resonance Lab, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Yi Lu
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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6
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Mirts EN, Bhagi-Damodaran A, Lu Y. Understanding and Modulating Metalloenzymes with Unnatural Amino Acids, Non-Native Metal Ions, and Non-Native Metallocofactors. Acc Chem Res 2019; 52:935-944. [PMID: 30912643 DOI: 10.1021/acs.accounts.9b00011] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Metalloproteins set the gold standard for performing important functions, including catalyzing demanding reactions under mild conditions. Designing artificial metalloenzymes (ArMs) to catalyze abiological reactions has been a major endeavor for many years, but most ArM activities are far below those of native enzymes, making them unsuitable for most pratical applications. A critical step to advance the field is to fundamentally understand what it takes to not only confer but also fine-tune ArM activities so they match those of native enzymes. Indeed, only once we can freely modulate ArM activity to rival (or surpass!) natural enzymes can the potential of ArMs be fully realized. A key to unlocking ArM potential is the observation that one metal primary coordination sphere can display a range of functions and levels of activity, leading to the realization that secondary coordination sphere (SCS) interactions are critically important. However, SCS interactions are numerous, long-range, and weak, making them very difficult to reproduce in ArMs. Furthermore, natural enzymes are tied to a small set of biologically available functional moieties from canonical amino acids and physiologically available metal ions and metallocofactors, severely limiting the chemical space available to probe and tune ArMs. In this Account, we summarize the use of unnatural amino acids (UAAs) and non-native metal ions and metallocofactors by our group and our collaborators to probe and modulate ArM functions. We incorporated isostructural UAAs in a type 1 copper (T1Cu) protein azurin to provide conclusive evidence that axial ligand hydrophobicity is a major determinant of T1Cu redunction potential ( E°'). Closely related work from other groups are also discussed. We also probed the role of protein backbone interactions that cannot be altered by standard mutagenesis by replacing the peptide bond with an ester linkage. We used insight gained from these studies to tune the E°' of azurin across the entire physiological range, the broadest range ever achieved in a single metalloprotein. Introducing UAA analogues of Tyr into ArM models of heme-copper oxidase (HCO) revealed a linear relationship between p Ka, E°', and activity. We also substituted non-native hemes and non-native metal ions for their native equivalents in these models to resolve several issues that were intractable in native HCOs and the closely related nitric oxide reductases, such as their roles in modulating substrate affinity, electron transfer rate, and activity. We incorporated abiological cofactors such as ferrocene and Mn(salen) into azurin and myoglobin, respectively, to stabilize these inorganic and organometallic compounds in water, confer abiological functions, tune their E°' and activity through SCS interactions, and show that the approach to metallocofactor anchoring and orientation can tune enantioselectivity and alter function. Replacing Cu in azurin with non-native Fe or Ni can impart novel activities, such as superoxide reduction and C-C bond formation. While progress was made, we have identified only a small fraction of the interactions that can be generally applied to ArMs to fine-tune their functions. Because SCS interactions are subtle and heavily interconnected, it has been difficult to characterize their effects quantitatively. It is vital to develop spectroscopic and computational techniques to detect and quantify their effects in both resting states and catalytic intermediates.
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Affiliation(s)
- Evan N. Mirts
- Department of Chemistry and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Ambika Bhagi-Damodaran
- Department of Chemistry and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Yi Lu
- Department of Chemistry and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
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7
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Ferentinos E, Chatziefthimiou S, Boudalis AK, Pissas M, Mathies G, Gast P, Groenen EJJ, Sanakis Y, Kyritsis P. The [Fe{(SePPh2
)2
N}2
] Complex Revisited: X-ray Crystallography, Magnetometry, High-Frequency EPR, and Mössbauer Studies Reveal Its Tetrahedral FeII
Se4
Coordination Sphere. Eur J Inorg Chem 2018. [DOI: 10.1002/ejic.201701459] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Eleftherios Ferentinos
- Inorganic Chemistry Laboratory; Department of Chemistry; National and Kapodistrian University of Athens; Panepistimiopolis 15771 Athens Greece
| | - Spyros Chatziefthimiou
- Institute of Nanoscience and Nanotechnology; N.C.S.R. “Demokritos”; Aghia Paraskevi 15310 Attiki Greece
| | - Athanassios K. Boudalis
- Institute of Nanoscience and Nanotechnology; N.C.S.R. “Demokritos”; Aghia Paraskevi 15310 Attiki Greece
| | - Michael Pissas
- Institute of Nanoscience and Nanotechnology; N.C.S.R. “Demokritos”; Aghia Paraskevi 15310 Attiki Greece
| | - Guinevere Mathies
- Huygens-Kamerlingh Onnes Laboratory; Department of Physics; Leiden University; Niels Bohrweg 2 2333 CA Leiden The Netherlands
| | - Peter Gast
- Huygens-Kamerlingh Onnes Laboratory; Department of Physics; Leiden University; Niels Bohrweg 2 2333 CA Leiden The Netherlands
| | - Edgar J. J. Groenen
- Huygens-Kamerlingh Onnes Laboratory; Department of Physics; Leiden University; Niels Bohrweg 2 2333 CA Leiden The Netherlands
| | - Yiannis Sanakis
- Institute of Nanoscience and Nanotechnology; N.C.S.R. “Demokritos”; Aghia Paraskevi 15310 Attiki Greece
| | - Panayotis Kyritsis
- Inorganic Chemistry Laboratory; Department of Chemistry; National and Kapodistrian University of Athens; Panepistimiopolis 15771 Athens Greece
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8
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Romero-Muñiz C, Ortega M, Vilhena JG, Díez-Pérez I, Cuevas JC, Pérez R, Zotti LA. Ab initio electronic structure calculations of entire blue copper azurins. Phys Chem Chem Phys 2018; 20:30392-30402. [DOI: 10.1039/c8cp06862c] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
We present a theoretical study of the blue-copper azurin extracted from Pseudomonas aeruginosa and several of its single amino acid mutants.
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Affiliation(s)
- Carlos Romero-Muñiz
- Departamento de Física Teórica de la Materia Condensada
- Universidad Autónoma de Madrid
- E-28049 Madrid
- Spain
| | - María Ortega
- Departamento de Física Teórica de la Materia Condensada
- Universidad Autónoma de Madrid
- E-28049 Madrid
- Spain
| | - J. G. Vilhena
- Departamento de Física Teórica de la Materia Condensada
- Universidad Autónoma de Madrid
- E-28049 Madrid
- Spain
- Department of Physics
| | - I. Díez-Pérez
- Department of Materials Science and Physical Chemistry & Institute of Theoretical and Computational Chemistry (IQTCUB)
- University of Barcelona
- Barcelona 08028
- Spain
- Department of Chemistry
| | - Juan Carlos Cuevas
- Departamento de Física Teórica de la Materia Condensada
- Universidad Autónoma de Madrid
- E-28049 Madrid
- Spain
- Condensed Matter Physics Center (IFIMAC)
| | - Rubén Pérez
- Departamento de Física Teórica de la Materia Condensada
- Universidad Autónoma de Madrid
- E-28049 Madrid
- Spain
- Condensed Matter Physics Center (IFIMAC)
| | - Linda A. Zotti
- Departamento de Física Teórica de la Materia Condensada
- Universidad Autónoma de Madrid
- E-28049 Madrid
- Spain
- Condensed Matter Physics Center (IFIMAC)
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9
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Biosynthetic approach to modeling and understanding metalloproteins using unnatural amino acids. Sci China Chem 2016. [DOI: 10.1007/s11426-016-0343-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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10
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Bhagi-Damodaran A, Hosseinzadeh P, Mirts E, Reed J, Petrik ID, Lu Y. Design of Heteronuclear Metalloenzymes. Methods Enzymol 2016; 580:501-37. [PMID: 27586347 PMCID: PMC5156654 DOI: 10.1016/bs.mie.2016.05.050] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Heteronuclear metalloenzymes catalyze some of the most fundamentally interesting and practically useful reactions in nature. However, the presence of two or more metal ions in close proximity in these enzymes makes them more difficult to prepare and study than homonuclear metalloenzymes. To meet these challenges, heteronuclear metal centers have been designed into small and stable proteins with rigid scaffolds to understand how these heteronuclear centers are constructed and the mechanism of their function. This chapter describes methods for designing heterobinuclear metal centers in a protein scaffold by giving specific examples of a few heme-nonheme bimetallic centers engineered in myoglobin and cytochrome c peroxidase. We provide step-by-step procedures on how to choose the protein scaffold, design a heterobinuclear metal center in the protein scaffold computationally, incorporate metal ions into the protein, and characterize the resulting metalloproteins, both structurally and functionally. Finally, we discuss how an initial design can be further improved by rationally tuning its secondary coordination sphere, electron/proton transfer rates, and the substrate affinity.
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Affiliation(s)
- A Bhagi-Damodaran
- University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - P Hosseinzadeh
- University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - E Mirts
- University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - J Reed
- University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - I D Petrik
- University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Y Lu
- University of Illinois at Urbana-Champaign, Urbana, IL, United States.
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11
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Yamaguchi T, Yano J, Yachandra VK, Nihei Y, Togashi H, Szilagyi RK, Kohzuma T. The Allosteric Regulation of Axial/Rhombic Population in a “Type 1” Copper Site: Multi-Edge X-ray Absorption Spectroscopic and Density Functional Studies of Pseudoazurin. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2015. [DOI: 10.1246/bcsj.20150225] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
| | - Junko Yano
- Physical Biosciences Division, Lawrence Berkeley National Laboratory
| | | | - Yuko Nihei
- Institute of Applied Beam Science, Ibaraki University
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12
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Zhang X, Liu X, Phillips DL, Zhao C. Mechanistic Insights Into the Factors That Influence the DNA Nuclease Activity of Mononuclear Facial Copper Complexes Containing Hetero-Substituted Cyclens. ACS Catal 2015. [DOI: 10.1021/acscatal.5b01735] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xuepeng Zhang
- MOE
Key Laboratory of Bioinorganic and Synthetic Chemistry, School of
Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, P. R. China
| | - Xueping Liu
- MOE
Key Laboratory of Bioinorganic and Synthetic Chemistry, School of
Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, P. R. China
| | - David Lee Phillips
- Department
of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - Cunyuan Zhao
- MOE
Key Laboratory of Bioinorganic and Synthetic Chemistry, School of
Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, P. R. China
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13
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Beedle AEM, Lezamiz A, Stirnemann G, Garcia-Manyes S. The mechanochemistry of copper reports on the directionality of unfolding in model cupredoxin proteins. Nat Commun 2015; 6:7894. [PMID: 26235284 PMCID: PMC4532836 DOI: 10.1038/ncomms8894] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 06/24/2015] [Indexed: 11/09/2022] Open
Abstract
Understanding the directionality and sequence of protein unfolding is crucial to elucidate the underlying folding free energy landscape. An extra layer of complexity is added in metalloproteins, where a metal cofactor participates in the correct, functional fold of the protein. However, the precise mechanisms by which organometallic interactions are dynamically broken and reformed on (un)folding are largely unknown. Here we use single molecule force spectroscopy AFM combined with protein engineering and MD simulations to study the individual unfolding pathways of the blue-copper proteins azurin and plastocyanin. Using the nanomechanical properties of the native copper centre as a structurally embedded molecular reporter, we demonstrate that both proteins unfold via two independent, competing pathways. Our results provide experimental evidence of a novel kinetic partitioning scenario whereby the protein can stochastically unfold through two distinct main transition states placed at the N and C termini that dictate the direction in which unfolding occurs.
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Affiliation(s)
- Amy E M Beedle
- Department of Physics, King's College London, London WC2R 2LS, UK
| | - Ainhoa Lezamiz
- Randall Division of Cell and Molecular Biophysics, King's College London, London WC2R 2LS, UK
| | - Guillaume Stirnemann
- CNRS - Institut de Biologie Physico-Chimique - PSL Research University, Laboratoire de Biochimie Théorique, 75005 Paris, France
| | - Sergi Garcia-Manyes
- Department of Physics, King's College London, London WC2R 2LS, UK.,Randall Division of Cell and Molecular Biophysics, King's College London, London WC2R 2LS, UK
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14
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Olson AC, Keith JM, Batista ER, Boland KS, Daly SR, Kozimor SA, MacInnes MM, Martin RL, Scott BL. Using solution- and solid-state S K-edge X-ray absorption spectroscopy with density functional theory to evaluate M-S bonding for MS4(2-) (M = Cr, Mo, W) dianions. Dalton Trans 2015; 43:17283-95. [PMID: 25311904 DOI: 10.1039/c4dt02302a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein, we have evaluated relative changes in M-S electronic structure and orbital mixing in Group 6 MS4(2-) dianions using solid- and solution-phase S K-edge X-ray absorption spectroscopy (XAS; M = Mo, W), as well as density functional theory (DFT; M = Cr, Mo, W) and time-dependent density functional theory (TDDFT) calculations. To facilitate comparison with solution measurements (conducted in acetonitrile), theoretical models included gas-phase calculations as well as those that incorporated an acetonitrile dielectric, the latter of which provided better agreement with experiment. Two pre-edge features arising from S 1s → e* and t electron excitations were observed in the S K-edge XAS spectra and were reasonably assigned as (1)A1 → (1)T2 transitions. For MoS4(2-), both solution-phase pre-edge peak intensities were consistent with results from the solid-state spectra. For WS4(2-), solution- and solid-state pre-edge peak intensities for transitions involving e* were equivalent, while transitions involving the t orbitals were less intense in solution. Experimental and computational results have been presented in comparison to recent analyses of MO4(2-) dianions, which allowed M-S and M-O orbital mixing to be evaluated as the principle quantum number (n) for the metal valence d orbitals increased (3d, 4d, 5d). Overall, the M-E (E = O, S) analyses revealed distinct trends in orbital mixing. For example, as the Group 6 triad was descended, e* (π*) orbital mixing remained constant in the M-S bonds, but increased appreciably for M-O interactions. For the t orbitals (σ* + π*), mixing decreased slightly for M-S bonding and increased only slightly for the M-O interactions. These results suggested that the metal and ligand valence orbital energies and radial extensions delicately influenced the orbital compositions for isoelectronic ME4(2-) (E = O, S) dianions.
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Affiliation(s)
- Angela C Olson
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
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15
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Wei C, Lazim R, Zhang D. Importance of polarization effect in the study of metalloproteins: application of polarized protein specific charge scheme in predicting the reduction potential of azurin. Proteins 2014; 82:2209-19. [PMID: 24753270 DOI: 10.1002/prot.24584] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 03/07/2014] [Accepted: 04/12/2014] [Indexed: 11/08/2022]
Abstract
Molecular dynamics (MD) simulation is commonly used in the study of protein dynamics, and in recent years, the extension of MD simulation to the study of metalloproteins is gaining much interest. Choice of force field is crucial in MD studies, and the inclusion of metal centers complicates the process of accurately describing the electrostatic environment that surrounds the redox centre. Herein, we would like to explore the importance of including electrostatic contribution from both protein and solvent in the study of metalloproteins. MD simulations with the implementation of thermodynamic integration will be conducted to model the reduction process of azurin from Pseudomonas aeruginosa. Three charge schemes will be used to derive the partial charges of azurin. These charge schemes differ in terms of the amount of immediate environment, respective to copper, considered during charge fitting, which ranges from the inclusion of copper and residues in the first coordination sphere during density functional theory charge fitting to the comprehensive inclusion of protein and solvent effect surrounding the metal centre using polarized protein-specific charge scheme. From the simulations conducted, the relative reduction potential of the mutated azurins respective to that of wild-type azurin (ΔEcal) were calculated and compared with experimental values. The ΔEcal approached experimental value with increasing consideration of environmental effect hence substantiating the importance of polarization effect in the study of metalloproteins. This study also attests the practicality of polarized protein-specific charge as a computational tool capable of incorporating both protein environment and solvent effect into MD simulations.
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Affiliation(s)
- Caiyi Wei
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore
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16
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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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17
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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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18
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Liu J, Chakraborty S, Hosseinzadeh P, Yu Y, Tian S, Petrik I, Bhagi A, Lu Y. Metalloproteins containing cytochrome, iron-sulfur, or copper redox centers. Chem Rev 2014; 114:4366-469. [PMID: 24758379 PMCID: PMC4002152 DOI: 10.1021/cr400479b] [Citation(s) in RCA: 560] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Indexed: 02/07/2023]
Affiliation(s)
- Jing Liu
- Department of Chemistry, Department of Biochemistry, and Center for Biophysics
and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Saumen Chakraborty
- Department of Chemistry, Department of Biochemistry, and Center for Biophysics
and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Parisa Hosseinzadeh
- Department of Chemistry, Department of Biochemistry, and Center for Biophysics
and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Yang Yu
- Department of Chemistry, Department of Biochemistry, and Center for Biophysics
and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Shiliang Tian
- Department of Chemistry, Department of Biochemistry, and Center for Biophysics
and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Igor Petrik
- Department of Chemistry, Department of Biochemistry, and Center for Biophysics
and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Ambika Bhagi
- Department of Chemistry, Department of Biochemistry, and Center for Biophysics
and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Yi Lu
- Department of Chemistry, Department of Biochemistry, and Center for Biophysics
and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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19
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Coutinho LH, Gardenghi DJ, Schlachter AS, de Souza GGB, Stolte WC. Positive and negative ion formation in deep-core excited molecules: S 1s excitation in dimethyl sulfoxide. J Chem Phys 2014; 140:024314. [PMID: 24437884 DOI: 10.1063/1.4861050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The photo-fragmentation of the dimethyl sulfoxide (DMSO) molecule was studied using synchrotron radiation and a magnetic mass spectrometer. The total cationic yield spectrum was recorded in the photon energy region around the sulfur K edge. The sulfur composition of the highest occupied molecular orbital's and lowest unoccupied molecular orbital's in the DMSO molecule has been obtained using both ab initio and density functional theory methods. Partial cation and anion-yield measurements were obtained in the same energy range. An intense resonance is observed at 2475.4 eV. Sulfur atomic ions present a richer structure around this resonant feature, as compared to other fragment ions. The yield curves are similar for most of the other ionic species, which we interpret as due to cascade Auger processes leading to multiply charged species which then undergo Coulomb explosion. The anions S(-), C(-), and O(-) are observed for the first time in deep-core-level excitation of DMSO.
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Affiliation(s)
- L H Coutinho
- Physics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-972, Brazil
| | - D J Gardenghi
- Department of Chemistry, University of Nevada, Las Vegas, Nevada 89154-4003, USA
| | - A S Schlachter
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - G G B de Souza
- Chemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21949-900, Brazil
| | - W C Stolte
- Department of Chemistry, University of Nevada, Las Vegas, Nevada 89154-4003, USA
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20
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Reschke S, Niks D, Wilson H, Sigfridsson KGV, Haumann M, Rajagopalan KV, Hille R, Leimkühler S. Effect of Exchange of the Cysteine Molybdenum Ligand with Selenocysteine on the Structure and Function of the Active Site in Human Sulfite Oxidase. Biochemistry 2013; 52:8295-303. [DOI: 10.1021/bi4008512] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Stefan Reschke
- Department
of Molecular Enzymology, Institute of Biochemistry and Biology, University of Potsdam, 14476 Potsdam, Germany
| | - Dimitri Niks
- Department
of Biochemistry, University of California, Riverside, California 92521, United States
| | - Heather Wilson
- Department
of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, United States
| | | | - Michael Haumann
- Institute
of Experimental Physics, Free University Berlin, 14195 Berlin, Germany
| | - K. V. Rajagopalan
- Department
of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, United States
| | - Russ Hille
- Department
of Biochemistry, University of California, Riverside, California 92521, United States
| | - Silke Leimkühler
- Department
of Molecular Enzymology, Institute of Biochemistry and Biology, University of Potsdam, 14476 Potsdam, Germany
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21
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22
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Wilson TD, Yu Y, Lu Y. Understanding copper-thiolate containing electron transfer centers by incorporation of unnatural amino acids and the CuA center into the type 1 copper protein azurin. Coord Chem Rev 2013. [DOI: 10.1016/j.ccr.2012.06.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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23
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Hadt RG, Sun N, Marshall NM, Hodgson KO, Hedman B, Lu Y, Solomon EI. Spectroscopic and DFT studies of second-sphere variants of the type 1 copper site in azurin: covalent and nonlocal electrostatic contributions to reduction potentials. J Am Chem Soc 2012; 134:16701-16. [PMID: 22985400 PMCID: PMC3506006 DOI: 10.1021/ja306438n] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The reduction potentials (E(0)) of type 1 (T1) or blue copper (BC) sites in proteins and enzymes with identical first coordination spheres around the redox active copper ion can vary by ~400 mV. Here, we use a combination of low-temperature electronic absorption and magnetic circular dichroism, electron paramagnetic resonance, resonance Raman, and S K-edge X-ray absorption spectroscopies to investigate a series of second-sphere variants--F114P, N47S, and F114N in Pseudomonas aeruginosa azurin--which modulate hydrogen bonding to and protein-derived dipoles nearby the Cu-S(Cys) bond. Density functional theory calculations correlated to the experimental data allow for the fractionation of the contributions to tuning E(0) into covalent and nonlocal electrostatic components. These are found to be significant, comparable in magnitude, and additive for active H-bonds, while passive H-bonds are mostly nonlocal electrostatic in nature. For dipoles, these terms can be additive to or oppose one another. This study provides a methodology for uncoupling covalency from nonlocal electrostatics, which, when coupled to X-ray crystallographic data, distinguishes specific local interactions from more long-range protein/active interactions, while affording further insight into the second-sphere mechanisms available to the protein to tune the E(0) of electron-transfer sites in biology.
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Affiliation(s)
- Ryan G. Hadt
- Department of Chemistry, Stanford University, Stanford, CA 94305
| | - Ning Sun
- Department of Chemistry, Stanford University, Stanford, CA 94305
| | - Nicholas M. Marshall
- Department of Chemistry, University of Illinois, Urbana-Champaign, Illinois 61801
| | - Keith O. Hodgson
- Department of Chemistry, Stanford University, Stanford, CA 94305
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025
| | - Britt Hedman
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025
| | - Yi Lu
- Department of Chemistry, University of Illinois, Urbana-Champaign, Illinois 61801
| | - Edward I. Solomon
- Department of Chemistry, Stanford University, Stanford, CA 94305
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025
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24
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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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25
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Daly SR, Keith JM, Batista ER, Boland KS, Clark DL, Kozimor SA, Martin RL. Sulfur K-edge X-ray Absorption Spectroscopy and Time-Dependent Density Functional Theory of Dithiophosphinate Extractants: Minor Actinide Selectivity and Electronic Structure Correlations. J Am Chem Soc 2012; 134:14408-22. [DOI: 10.1021/ja303999q] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Scott R. Daly
- Los Alamos National Laboratory, Los Alamos,
New Mexico 87545, United States
| | - Jason M. Keith
- Los Alamos National Laboratory, Los Alamos,
New Mexico 87545, United States
| | - Enrique R. Batista
- Los Alamos National Laboratory, Los Alamos,
New Mexico 87545, United States
| | - Kevin S. Boland
- Los Alamos National Laboratory, Los Alamos,
New Mexico 87545, United States
| | - David L. Clark
- Los Alamos National Laboratory, Los Alamos,
New Mexico 87545, United States
| | - Stosh A. Kozimor
- Los Alamos National Laboratory, Los Alamos,
New Mexico 87545, United States
| | - Richard L. Martin
- Los Alamos National Laboratory, Los Alamos,
New Mexico 87545, United States
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26
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Hadt RG, Xie X, Pauleta SR, Moura I, Solomon EI. Analysis of resonance Raman data on the blue copper site in pseudoazurin: excited state π and σ charge transfer distortions and their relation to ground state reorganization energy. J Inorg Biochem 2012; 115:155-62. [PMID: 22560510 DOI: 10.1016/j.jinorgbio.2012.03.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2012] [Revised: 03/18/2012] [Accepted: 03/21/2012] [Indexed: 10/28/2022]
Abstract
The short Cu(2+)-S(Met) bond in pseudoazurin (PAz) results in the presence of two relatively intense S(p)(π) and S(p)(σ) charge transfer (CT) transitions. This has enabled resonance Raman (rR) data to be obtained for each excited state. The rR data show very different intensity distribution patterns for the vibrations in the 300-500 cm(-1) region. Time-dependent density functional theory (TDDFT) calculations have been used to determine that the change in intensity distribution between the S(p)(π) and S(p)(σ) excited states reflects the differential enhancement of S(Cys) backbone modes with Cu-S(Cys)-C(β) out-of-plane (oop) and in-plane (ip) bend character in their respective potential energy distributions (PEDs). The rR excited state distortions have been related to ground state reorganization energies (λ s) and predict that, in addition to M-L stretches, the Cu-S(Cys)-C(β) oop bend needs to be considered. DFT calculations predict a large distortion in the Cu-S(Cys)-C(β) oop bending coordinate upon reduction of a blue copper (BC) site; however, this distortion is not present in the X-ray crystal structures of reduced BC sites. The lack of Cu-S(Cys)-C(β) oop distortion upon reduction corresponds to a previously unconsidered constraint on the thiolate ligand orientation in the reduced state of BC proteins and can be considered as a contribution to the entatic/rack nature of BC sites.
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Affiliation(s)
- Ryan G Hadt
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
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27
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Abstract
Odorant receptors (ORs) in olfactory sensory neurons (OSNs) mediate detection of volatile odorants. Divalent sulfur compounds, such as thiols and thioethers, are extremely potent odorants. We identify a mouse OR, MOR244-3, robustly responding to (methylthio)methanethiol (MeSCH(2)SH; MTMT) in heterologous cells. Found specifically in male mouse urine, strong-smelling MTMT [human threshold 100 parts per billion (ppb)] is a semiochemical that attracts female mice. Nonadjacent thiol and thioether groups in MTMT suggest involvement of a chelated metal complex in MOR244-3 activation. Metal ion involvement in thiol-OR interactions was previously proposed, but whether these ions change thiol-mediated OR activation remained unknown. We show that copper ion among all metal ions tested is required for robust activation of MOR244-3 toward ppb levels of MTMT, structurally related sulfur compounds, and other metal-coordinating odorants (e.g., strong-smelling trans-cyclooctene) among >125 compounds tested. Copper chelator (tetraethylenepentamine, TEPA) addition abolishes the response of MOR244-3 to MTMT. Histidine 105, located in the third transmembrane domain near the extracellular side, is proposed to serve as a copper-coordinating residue mediating interaction with the MTMT-copper complex. Electrophysiological recordings of the OSNs in the septal organ, abundantly expressing MOR244-3, revealed neurons responding to MTMT. Addition of copper ion and chelator TEPA respectively enhanced and reduced the response of some MTMT-responding neurons, demonstrating the physiological relevance of copper ion in olfaction. In a behavioral context, an olfactory discrimination assay showed that mice injected with TEPA failed to discriminate MTMT. This report establishes the role of metal ions in mammalian odor detection by ORs.
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28
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Pollock CJ, DeBeer S. Valence-to-core X-ray emission spectroscopy: a sensitive probe of the nature of a bound ligand. J Am Chem Soc 2011; 133:5594-601. [PMID: 21417349 DOI: 10.1021/ja200560z] [Citation(s) in RCA: 109] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The sensitivity of iron Kβ X-ray emission spectroscopy (XES) to the nature of the bound ligands (σ-donating, π-donating, and π-accepting) has been explored. A combination of experiment and theory has been employed, with a DFT approach being utilized to elucidate ligand effects on the spectra and to assign the spectral intensity mechanisms. Knowledge of the various contributions to the spectra allows for a deeper understanding of spectral features and demonstrates the sensitivity of this method to the identity of the interacting ligands. The potential of XES for identifying intermediate species in nonheme iron enzymes is highlighted.
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Affiliation(s)
- Christopher J Pollock
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA
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29
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Siluvai GS, Nakano M, Mayfield M, Blackburn NJ. The essential role of the Cu(II) state of Sco in the maturation of the Cu(A) center of cytochrome oxidase: evidence from H135Met and H135SeM variants of the Bacillus subtilis Sco. J Biol Inorg Chem 2010; 16:285-97. [PMID: 21069401 DOI: 10.1007/s00775-010-0725-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Accepted: 10/19/2010] [Indexed: 01/24/2023]
Abstract
Sco is a red copper protein that plays an essential yet poorly understood role in the metalation of the Cu(A) center of cytochrome oxidase, and is stable in both the Cu(I) and Cu(II) forms. To determine which oxidation state is important for function, we constructed His135 to Met or selenomethionine (SeM) variants that were designed to stabilize the Cu(I) over the Cu(II) state. H135M was unable to complement a scoΔ strain of Bacillus subtilis, indicating that the His to Met substitution abrogated cytochrome oxidase maturation. The Cu(I) binding affinities of H135M and H135SeM were comparable to that of the WT and 100-fold tighter than that of the H135A variant. The coordination chemistry of the H135M and H135SeM variants was studied by UV/vis, EPR, and XAS spectroscopy in both the Cu(I) and the Cu(II) forms. Both oxidation states bound copper via the S atoms of C45, C49 and M135. In particular, EXAFS data collected at both the Cu and the Se edges of the H135SeM derivative provided unambiguous evidence for selenomethionine coordination. Whereas the coordination chemistry and copper binding affinity of the Cu(I) state closely resembled that of the WT protein, the Cu(II) state was unstable, undergoing autoreduction to Cu(I). H135M also reacted faster with H(2)O(2) than WT Sco. These data, when coupled with the complete elimination of function in the H135M variant, imply that the Cu(I) state cannot be the sole determinant of function; the Cu(II) state must be involved in function at some stage of the reaction cycle.
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Affiliation(s)
- Gnana S Siluvai
- Division of Environmental and Biomolecular Systems, Oregon Health and Sciences University, 20000 NW Walker Road, Beaverton, OR 97006, USA
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30
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McMaster J, Oganesyan VS. Magnetic circular dichroism spectroscopy as a probe of the structures of the metal sites in metalloproteins. Curr Opin Struct Biol 2010; 20:615-22. [PMID: 20619632 DOI: 10.1016/j.sbi.2010.06.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Revised: 06/07/2010] [Accepted: 06/09/2010] [Indexed: 11/30/2022]
Abstract
Magnetic circular dichroism (MCD) is a powerful probe of the electronic and geometric structures of metal centres in metalloproteins. MCD has provided significant insight into the nature of the axial donors at haem centres and, more recently, sophisticated methods for the analysis of MCD spectra have had a major impact on the study of the electronic structures of the ground states of a range of Cu, non-haem iron and Mo-containing active sites. This detail, together with data from other complimentary spectroscopies, has played a major role in defining the chemistry underpinning the catalysis achieved by these metal centres.
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Affiliation(s)
- Jonathan McMaster
- School of Chemistry, The University of Nottingham, Nottingham NG7 2RD, UK.
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31
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Rajapandian V, Hakkim V, Subramanian V. Molecular Dynamics Studies on Native, Loop-Contracted, and Metal Ion-Substituted Azurins. J Phys Chem B 2010; 114:8474-86. [DOI: 10.1021/jp911301v] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- V. Rajapandian
- Chemical Laboratory, Central Leather Research Institute, Council of Scientific and Industrial Research, Adyar, Chennai 600 020, India
| | - V. Hakkim
- Chemical Laboratory, Central Leather Research Institute, Council of Scientific and Industrial Research, Adyar, Chennai 600 020, India
| | - V. Subramanian
- Chemical Laboratory, Central Leather Research Institute, Council of Scientific and Industrial Research, Adyar, Chennai 600 020, India
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32
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Cramer CJ, Truhlar DG. Density functional theory for transition metals and transition metal chemistry. Phys Chem Chem Phys 2009; 11:10757-816. [PMID: 19924312 DOI: 10.1039/b907148b] [Citation(s) in RCA: 1079] [Impact Index Per Article: 71.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We introduce density functional theory and review recent progress in its application to transition metal chemistry. Topics covered include local, meta, hybrid, hybrid meta, and range-separated functionals, band theory, software, validation tests, and applications to spin states, magnetic exchange coupling, spectra, structure, reactivity, and catalysis, including molecules, clusters, nanoparticles, surfaces, and solids.
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Affiliation(s)
- Christopher J Cramer
- Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, MN 55455-0431, USA.
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33
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Rajapandian V, Raman SS, Hakkim V, Parthasarathi R, Subramanian V. Molecular mechanics and molecular dynamics study on azurin using extensible and systematic force field (ESFF). ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.theochem.2009.04.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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34
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Rajapandian V, Hakkim V, Subramanian V. ONIOM Calculation on Azurin: Effect of Metal Ion Substitutions. J Phys Chem A 2009; 113:8615-25. [DOI: 10.1021/jp900451f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- V. Rajapandian
- Chemical Laboratory, Central Leather Research Institute, Council of Scientific and Industrial Research, Adyar, Chennai 600 020, India
| | - V. Hakkim
- Chemical Laboratory, Central Leather Research Institute, Council of Scientific and Industrial Research, Adyar, Chennai 600 020, India
| | - V. Subramanian
- Chemical Laboratory, Central Leather Research Institute, Council of Scientific and Industrial Research, Adyar, Chennai 600 020, India
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35
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Probing the role of the proximal heme ligand in cytochrome P450cam by recombinant incorporation of selenocysteine. Proc Natl Acad Sci U S A 2009; 106:5481-6. [PMID: 19293375 DOI: 10.1073/pnas.0810503106] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The unique monooxygenase activity of cytochrome P450cam has been attributed to coordination of a cysteine thiolate to the heme cofactor. To investigate this interaction, we replaced cysteine with the more electron-donating selenocysteine. Good yields of the selenoenzyme were obtained by bacterial expression of an engineered gene containing the requisite UGA codon for selenocysteine and a simplified yet functional selenocysteine insertion sequence (SECIS). The sulfur-to-selenium substitution subtly modulates the structural, electronic, and catalytic properties of the enzyme. Catalytic activity decreases only 2-fold, whereas substrate oxidation becomes partially uncoupled from electron transfer, implying a more complex role for the axial ligand than generally assumed.
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36
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Lucas HR, Karlin KD. Copper-Carbon Bonds in Mechanistic and Structural Probing of Proteins as well as in Situations where Copper is a Catalytic or Receptor Site. METAL-CARBON BONDS IN ENZYMES AND COFACTORS 2009. [DOI: 10.1039/9781847559333-00295] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
While copper-carbon bonds are well appreciated in organometallic synthetic chemistry, such occurrences are less known in biological settings. By far, the greatest incidence of copper-carbon moieties is in bioinorganic research aimed at probing copper protein active site structure and mechanism; for example, carbon monoxide (CO) binding as a surrogate for O2. Using infrared (IR) spectroscopy, CO coordination to cuprous sites has proven to be an extremely useful tool for determining active site copper ligation (e.g., donor atom number and type). The coupled (hemocyanin, tyrosinase, catechol oxidase) and non-coupled (peptidylglycine α-hydroxylating monooxygenase, dopamine β-monooxygenase) binuclear copper proteins as well as the heme-copper oxidases (HCOs) have been studied extensively via this method. In addition, environmental changes within the vicinity of the active site have been determined based on shifts in the CO stretching frequencies, such as for copper amine oxidases, nitrite reductases and again in the binuclear proteins and HCOs. In many situations, spectroscopic monitoring has provided kinetic and thermodynamic data on CuI-CO formation and CO dissociation from copper(I); recently, processes occurring on a femtosecond timescale have been reported. Copper-cyano moieties have also been useful for obtaining insights into the active site structure and mechanisms of copper-zinc superoxide dismutase, azurin, nitrous oxide reductase, and multi-copper oxidases. Cyanide is a good ligand for both copper(I) and copper(II), therefore multiple physical-spectroscopic techniques can be applied. A more obvious occurrence of a “Cu-C” moiety was recently described for a CO dehydrogenase which contains a novel molybdenum-copper catalytic site. A bacterial copper chaperone (CusF) was recently established to have a novel d-π interaction comprised of copper(I) with the arene containing side-chain of a tryptophan amino acid residue. Meanwhile, good evidence exists that a plant receptor site (ETR1) utilizes copper(I) to sense ethylene, a growth hormone. A copper olfactory receptor has also been suggested. All of the above mentioned occurrences or uses of carbon-containing substrates and/or probes are reviewed and discussed within the framework of copper proteins and other relevant systems.
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Affiliation(s)
- Heather R. Lucas
- Department of Chemistry, The Johns Hopkins University 3400 N. Charles Street Baltimore MD 21218 USA
| | - Kenneth D. Karlin
- Department of Chemistry, The Johns Hopkins University 3400 N. Charles Street Baltimore MD 21218 USA
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37
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Abstract
Metalloproteins contain highly specialized metal-binding sites that are designed to accept specific metal ions to maintain correct function. Although many of the sites have been modified with success, the relative paucity of functional group availability within proteinogenic amino acids can sometimes leave open questions about specific functions of the metal binding ligands. Attaining a more thorough analysis of individual amino acid function within metalloproteins has been realized using expressed protein ligation (EPL). Here we describe our recent efforts using EPL to incorporate nonproteinogenic cysteine and methionine analogues into the type 1 copper site found in Pseudomonas aeruginosa azurin.
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Affiliation(s)
- Kevin M. Clark
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Wilfred van der Donk
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Yi Lu
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
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Emam SM, McArdle P, McManus J, Mahon M. Ring opening complexation of nickel(II) and copper(II) by 2-phenyl-2-(2-pyridyl)imidazolidine: Synthesis, spectra and X-ray crystal structures. Polyhedron 2008. [DOI: 10.1016/j.poly.2008.04.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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