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Lim H, Baker ML, Cowley RE, Kim S, Bhadra M, Siegler MA, Kroll T, Sokaras D, Weng TC, Biswas DR, Dooley DM, Karlin KD, Hedman B, Hodgson KO, Solomon EI. Kβ X-ray Emission Spectroscopy as a Probe of Cu(I) Sites: Application to the Cu(I) Site in Preprocessed Galactose Oxidase. Inorg Chem 2020; 59:16567-16581. [PMID: 33136386 DOI: 10.1021/acs.inorgchem.0c02495] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cu(I) active sites in metalloproteins are involved in O2 activation, but their O2 reactivity is difficult to study due to the Cu(I) d10 closed shell which precludes the use of conventional spectroscopic methods. Kβ X-ray emission spectroscopy (XES) is a promising technique for investigating Cu(I) sites as it detects photons emitted by electronic transitions from occupied orbitals. Here, we demonstrate the utility of Kβ XES in probing Cu(I) sites in model complexes and a metalloprotein. Using Cu(I)Cl, emission features from double-ionization (DI) states are identified using varying incident X-ray photon energies, and a reasonable method to correct the data to remove DI contributions is presented. Kβ XES spectra of Cu(I) model complexes, having biologically relevant N/S ligands and different coordination numbers, are compared and analyzed, with the aid of density functional theory (DFT) calculations, to evaluate the sensitivity of the spectral features to the ligand environment. While the low-energy Kβ2,5 emission feature reflects the ionization energy of ligand np valence orbitals, the high-energy Kβ2,5 emission feature corresponds to transitions from molecular orbitals (MOs) having mainly Cu 3d character with the intensities determined by ligand-mediated d-p mixing. A Kβ XES spectrum of the Cu(I) site in preprocessed galactose oxidase (GOpre) supports the 1Tyr/2His structural model that was determined by our previous X-ray absorption spectroscopy and DFT study. The high-energy Kβ2,5 emission feature in the Cu(I)-GOpre data has information about the MO containing mostly Cu 3dx2-y2 character that is the frontier molecular orbital (FMO) for O2 activation, which shows the potential of Kβ XES in probing the Cu(I) FMO associated with small-molecule activation in metalloproteins.
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Affiliation(s)
- Hyeongtaek Lim
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Michael L Baker
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Ryan E Cowley
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Sunghee Kim
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Mayukh Bhadra
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Maxime A Siegler
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Thomas Kroll
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Dimosthenis Sokaras
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Tsu-Chien Weng
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Dalia R Biswas
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - David M Dooley
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States.,University of Rhode Island, Kingston, Rhode Island 02881, United States
| | - Kenneth D Karlin
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Britt Hedman
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Keith O Hodgson
- Department of Chemistry, Stanford University, Stanford, California 94305, United States.,Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Edward I Solomon
- Department of Chemistry, Stanford University, Stanford, California 94305, United States.,Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
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Martinie RJ, Blaesi EJ, Bollinger JM, Krebs C, Finkelstein KD, Pollock CJ. Two-Color Valence-to-Core X-ray Emission Spectroscopy Tracks Cofactor Protonation State in a Class I Ribonucleotide Reductase. Angew Chem Int Ed Engl 2018; 57:12754-12758. [PMID: 30075052 PMCID: PMC6579043 DOI: 10.1002/anie.201807366] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 07/20/2018] [Indexed: 12/20/2022]
Abstract
Proton transfer reactions are of central importance to a wide variety of biochemical processes, though determining proton location and monitoring proton transfers in biological systems is often extremely challenging. Herein, we use two-color valence-to-core X-ray emission spectroscopy (VtC XES) to identify protonation events across three oxidation states of the O2 -activating, radical-initiating manganese-iron heterodinuclear cofactor in a class I-c ribonucleotide reductase. This is the first application of VtC XES to an enzyme intermediate and the first simultaneous measurement of two-color VtC spectra. In contrast to more conventional methods of assessing protonation state, VtC XES is a more direct probe applicable to a wide range of metalloenzyme systems. These data, coupled to insight provided by DFT calculations, allow the inorganic cores of the MnIV FeIV and MnIV FeIII states of the enzyme to be assigned as MnIV (μ-O)2 FeIV and MnIV (μ-O)(μ-OH)FeIII , respectively.
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Affiliation(s)
- Ryan J Martinie
- Department of Chemistry, The Pennsylvania State University, 318 Chemistry Building, University Park, PA, 16802, USA
| | - Elizabeth J Blaesi
- Department of Chemistry, The Pennsylvania State University, 318 Chemistry Building, University Park, PA, 16802, USA
| | - J Martin Bollinger
- Department of Chemistry and Department of Biochemistry and Molecular Biology, The Pennsylvania State University, 318 Chemistry Building, University Park, PA, 16802, USA
| | - Carsten Krebs
- Department of Chemistry and Department of Biochemistry and Molecular Biology, The Pennsylvania State University, 318 Chemistry Building, University Park, PA, 16802, USA
| | - Kenneth D Finkelstein
- Cornell High Energy Synchrotron Source, Wilson Laboratory, Cornell University, Ithaca, NY, 14853, USA
| | - Christopher J Pollock
- Department of Chemistry, The Pennsylvania State University, 318 Chemistry Building, University Park, PA, 16802, USA
- Present address: Cornell High Energy Synchrotron Source, Wilson Laboratory, Cornell University, Ithaca, NY, 14853, USA
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Martinie RJ, Blaesi EJ, Bollinger JM, Krebs C, Finkelstein KD, Pollock CJ. Two‐Color Valence‐to‐Core X‐ray Emission Spectroscopy Tracks Cofactor Protonation State in a Class I Ribonucleotide Reductase. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201807366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Ryan J. Martinie
- Department of Chemistry The Pennsylvania State University 318 Chemistry Building University Park PA 16802 USA
| | - Elizabeth J. Blaesi
- Department of Chemistry The Pennsylvania State University 318 Chemistry Building University Park PA 16802 USA
| | - J. Martin Bollinger
- Department of Chemistry and Department of Biochemistry and Molecular Biology The Pennsylvania State University 318 Chemistry Building University Park PA 16802 USA
| | - Carsten Krebs
- Department of Chemistry and Department of Biochemistry and Molecular Biology The Pennsylvania State University 318 Chemistry Building University Park PA 16802 USA
| | - Kenneth D. Finkelstein
- Cornell High Energy Synchrotron Source, Wilson Laboratory Cornell University Ithaca NY 14853 USA
| | - Christopher J. Pollock
- Department of Chemistry The Pennsylvania State University 318 Chemistry Building University Park PA 16802 USA
- Present address: Cornell High Energy Synchrotron Source Wilson Laboratory Cornell University Ithaca NY 14853 USA
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Colomban C, Philouze C, Molton F, Leconte N, Thomas F. Copper(II) complexes of N3O ligands as models for galactose oxidase: Effect of variation of steric bulk of coordinated phenoxyl moiety on the radical stability and spectroscopy. Inorganica Chim Acta 2018. [DOI: 10.1016/j.ica.2017.09.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Martin-Diaconescu V, Chacón KN, Delgado-Jaime MU, Sokaras D, Weng TC, DeBeer S, Blackburn NJ. Kβ Valence to Core X-ray Emission Studies of Cu(I) Binding Proteins with Mixed Methionine - Histidine Coordination. Relevance to the Reactivity of the M- and H-sites of Peptidylglycine Monooxygenase. Inorg Chem 2016; 55:3431-9. [PMID: 26965786 PMCID: PMC4878823 DOI: 10.1021/acs.inorgchem.5b02842] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Biological systems use copper as a redox center in many metalloproteins, where the role of the metal is to cycle between its +1 and +2 oxidation states. This chemistry requires the redox potential to be in a range that can stabilize both Cu(I) and Cu(II) states and often involves protein-derived ligand sets involving mixed histidine-methionine coordination that balance the preferences of both oxidation states. Transport proteins, on the other hand, utilize copper in the Cu(I) state and often contain sites comprised predominately of the cuprophilic residue methionine. The electronic factors that allow enzymes and transporters to balance their redox requirements are complex and are often elusive due to the dearth of spectroscopic probes of the Cu(I) state. Here we present the novel application of X-ray emission spectroscopy to copper proteins via a study of a series of mixed His-Met copper sites where the ligand set varies in a systematic way between the His3 and Met3 limits. The sites are derived from the wild-type peptidylglycine monooxygenase (PHM), two single-site variants which replicate each of its two copper sites (CuM-site and CuH-site), and the transporters CusF and CusB. Clear differences are observed in the Kβ2,5 region at the Met3 and His3 limits. CusB (Met3) has a distinct peak at 8978.4 eV with a broad shoulder at 8975.6 eV, whereas CuH (His3) has two well-resolved features: a more intense feature at 8974.8 eV and a second at 8977.2 eV. The mixed coordination sphere CusF (Met2His) and the PHM CuM variant (Met1His2) have very similar spectra consisting of two features at 8975.2 and 8977.8 eV. An analysis of DFT calculated spectra indicate that the intensity of the higher energy peak near 8978 eV is mediated by mixing of ligand-based orbitals into the Cu d(10) manifold, with S from Met providing more intensity by facilitating increased Cu p-d mixing. Furthermore, reaction of WT PHM with CO (an oxygen analogue) produced the M site CO complex, which showed a unique XES spectrum that could be computationally reproduced by including interactions between Cu(I) and the CO ligand. The study suggests that the valence-to-core (VtC) region can not only serve as a probe of ligand speciation but also offer insight into the coordination geometry, in a fashion similar to XAS pre-edges, and may be sufficiently sensitive to the coordination of exogenous ligands to be useful in the study of reaction mechanisms.
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Affiliation(s)
- Vlad Martin-Diaconescu
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34 – 36, D-45470 Mülheim an der Ruhr, Mülheim an der Ruhr, Germany
| | - Kelly N. Chacón
- Institute of Environmental Health, Oregon Health & Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97239
| | - Mario Ulises Delgado-Jaime
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34 – 36, D-45470 Mülheim an der Ruhr, Mülheim an der Ruhr, Germany
| | - Dimosthenis Sokaras
- Stanford Synchrotron Radiation Lightsource, 2575 Sand Hill Road, Menlo Park, CA 97025
| | - Tsu-Chien Weng
- Stanford Synchrotron Radiation Lightsource, 2575 Sand Hill Road, Menlo Park, CA 97025
| | - Serena DeBeer
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34 – 36, D-45470 Mülheim an der Ruhr, Mülheim an der Ruhr, Germany
- Cornell University, Department of Chemistry and Chemical Biology, Ithaca, New York, 14853, United States
| | - Ninian J. Blackburn
- Institute of Environmental Health, Oregon Health & Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97239
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Safaei E, Hajikhanmirzaei L, Karimi B, Wojtczak A, Cotič P, Lee YI. TEMPO-mediated aerobic oxidation of alcohols using copper(II) complex of bis(phenol) di-amine ligand as biomimetic model for Galactose oxidase enzyme. Polyhedron 2016. [DOI: 10.1016/j.poly.2015.11.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ghorai S, Sarmah A, Roy RK, Tiwari A, Mukherjee C. Effect of Geometrical Distortion on the Electronic Structure: Synthesis and Characterization of Monoradical-Coordinated Mononuclear Cu(II) Complexes. Inorg Chem 2016; 55:1370-80. [PMID: 26812584 DOI: 10.1021/acs.inorgchem.5b01257] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ligand H3Sami(Mixed(tBu)) was composed of two different compartments, a redox-active 2-aminophenol and a salen salicylidene. Both compartments were linked via a benzyl linker. The ligand reacted with CuCl2·2H2O under air in the presence of Et3N and provided the corresponding monoradical-coordinated mononuclear Cu(II) complex (1). Complex 1, in solution, reacted with air and provided complex 2 via ligand-centered oxygenation at the benzyl-CH2 position. Both complexes were characterized via IR, mass spectrometry, X-ray single-crystal diffraction, variable-temperature magnetic susceptibility, cyclic voltammograms (CVs), and UV-vis/NIR spectroscopic techniques. X-ray crystallographic analyses clearly showed almost equally distorted square planar geometry around the Cu(II) atom in both complexes. However, the bending of the radical-containing C6 ring compared to the N1-Cu1-O1 plane was different in both complexes. While complex 1 was paramagnetic and showed a ferromagnetic coupling between the d(x(2)-y(2)) magnetic orbital of Cu(II) ion and the p(z) orbital of coordinated π-radical, complex 2 was diamagnetic by experiencing a strong antiferromagnetic coupling between the two magnetic orbitals. UV-vis/NIR spectra of the complexes were dominated by charge-transfer transitions. CVs of the complexes showed two reversible one-electron oxidations and one reversible one-electron reduction. E(1/2)(ox2) and E(1/2)(red1) potentials were different in both complexes, while E(1/2)(ox1) values were almost the same and the process corresponded to the formation of phenoxyl radical. Theoretical studies were also performed to understand the magnetic coupling phenomena, and TD-DFT calculations were employed for the assignment of charge-transfer absorption bands.
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Affiliation(s)
- Samir Ghorai
- Department of Chemistry, Indian Institute of Technology Guwahati , Guwahati, 781039 Assam, India
| | - Amrit Sarmah
- Department of Chemistry, Birla Institute of Technology and Science (BITS) , Pilani, 333031 Rajasthan, India
| | - Ram Kinkar Roy
- Department of Chemistry, Birla Institute of Technology and Science (BITS) , Pilani, 333031 Rajasthan, India
| | - Archana Tiwari
- Department of Physics, School of Physical Sciences, Sikkim University , Gangtok 737102 Sikkim, India
| | - Chandan Mukherjee
- Department of Chemistry, Indian Institute of Technology Guwahati , Guwahati, 781039 Assam, India
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Mijovilovich A. Delta-mu XANES reveals the electronic structure of the adsorption of propene on gold nanoparticles. RSC Adv 2014. [DOI: 10.1039/c3ra47209d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Experimental delta-mu spectra for the H oxidated and the propene co-fed Au nanoparticles were reproduced with XANES simulations with FEFF9. The results support that the propene has pi back-bonding to the Au with binding at defects or steps or in very small nanoparticles. Cationic, or even better, the neutrally charged Au nanoparticles, reproduce the experimental results of the propene co-fed catalyst found in the literature.
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Affiliation(s)
- Ana Mijovilovich
- Inorganic Chemistry and Catalysis group
- Utrecht University
- 3584 CG Utrecht, The Netherlands
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Leidel N, Chernev P, Havelius KGV, Ezzaher S, Ott S, Haumann M. Site-Selective X-ray Spectroscopy on an Asymmetric Model Complex of the [FeFe] Hydrogenase Active Site. Inorg Chem 2012; 51:4546-59. [DOI: 10.1021/ic2024154] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Nils Leidel
- Freie Universität Berlin, Institut für Experimentalphysik, 14195
Berlin, Germany
| | - Petko Chernev
- Freie Universität Berlin, Institut für Experimentalphysik, 14195
Berlin, Germany
| | - Kajsa G. V. Havelius
- Freie Universität Berlin, Institut für Experimentalphysik, 14195
Berlin, Germany
| | - Salah Ezzaher
- University of Uppsala, Department of Chemistry, Ångström
Laboratories, 75120
Uppsala, Sweden
| | - Sascha Ott
- University of Uppsala, Department of Chemistry, Ångström
Laboratories, 75120
Uppsala, Sweden
| | - Michael Haumann
- Freie Universität Berlin, Institut für Experimentalphysik, 14195
Berlin, Germany
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Mijovilovich A, Hayashi H, Kawamura N, Osawa H, Bruijnincx PCA, Klein Gebbink RJM, de Groot FMF, Weckhuysen BM. Kβ Detected High-Resolution XANES of FeII and FeIII Models of the 2-His-1-Carboxylate Motif: Analysis of the Carboxylate Binding Mode. Eur J Inorg Chem 2012. [DOI: 10.1002/ejic.201101075] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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