1
|
Miller PD, Mengell J, Shultz DA, Kirk ML. Metal-Ligand Exchange Coupling Alters the Open-Shell Ligand Electronic Structure in a Bis(semiquinone) Complex. Inorg Chem 2024; 63:6493-6499. [PMID: 38517353 DOI: 10.1021/acs.inorgchem.4c00380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2024]
Abstract
The electronic structure of the bis(dioxolene) bridging ligand -SQ2Th2- is responsive to metal-ligand magnetic exchange coupling. Comparison of the crystal structure of (NiSQ)2Th2 to that of (ZnSQ)2Th2 indicates an open-shell biradical ground state for the dinuclear Ni(II) complex compared to the closed-shell quinoidal character found in the dinuclear Zn(II) complex. Consistent with a comparison of bond lengths obtained by X-ray diffraction, the analysis of the variable-temperature magnetic susceptibility data for crystalline (NiSQ)2Th2 yields reduced SQ-SQ radical-radical magnetic exchange coupling (JSQ-SQ = -203 cm-1) compared to that of (ZnSQ)2Th2 (JSQ-SQ = -321 cm-1). The reduced SQ-SQ exchange coupling in (NiSQ)2Th2 derives from an attenuation of the SQ spin densities, which in turn is derived from the Ni-SQ antiferromagnetic exchange interactions. This reduction in SQ--SQ exchange that we observe for (NiSQ)2Th2 correlates with an effective lengthening of the bridge unit by ∼2.1 Å relative to that of (ZnSQ)2Th2. This magnitude of the effective increase in the bridge distance is consistent with the (NiSQ)2Th2 JSQ-SQ value lying between those of (ZnSQ)2Th2 and (ZnSQ)2Th3. The ability to modulate spin populations on an organic radical via pairwise Ni-SQ magnetic exchange interactions is a general way to affect electronic coupling in the Th-Th bridge. Our results suggest that metal-radical exchange coupling represents a powerful mechanism for tuning organic molecular electronic structure, with important implications for molecular electronics and molecular electron transport.
Collapse
Affiliation(s)
- Paul D Miller
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Joshua Mengell
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
| | - David A Shultz
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Martin L Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
- The Center for High Technology Materials, The University of New Mexico, Albuquerque, New Mexico 87106, United States
- Center for Quantum Information and Control (CQuIC), The University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
- Center for Computational Chemistry, The University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
| |
Collapse
|
2
|
Panda S, Phan H, Karlin KD. Heme-copper and Heme O 2-derived synthetic (bioinorganic) chemistry toward an understanding of cytochrome c oxidase dioxygen chemistry. J Inorg Biochem 2023; 249:112367. [PMID: 37742491 PMCID: PMC10615892 DOI: 10.1016/j.jinorgbio.2023.112367] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/22/2023] [Accepted: 09/07/2023] [Indexed: 09/26/2023]
Abstract
Cytochrome c oxidase (CcO), also widely known as mitochondrial electron-transport-chain complex IV, is a multi-subunit transmembrane protein responsible for catalyzing the last step of the electron transport chain, dioxygen reduction to water, which is essential to the establishment and maintenance of the membrane proton gradient that drives ATP synthesis. Although many intermediates in the CcO catalytic cycle have been spectroscopically and/or computationally authenticated, the specifics regarding the IP intermediate, hypothesized to be a heme-Cu (hydro)peroxo species whose O-O bond homolysis is supported by a hydrogen-bonding network of water molecules, are largely obscured by the fast kinetics of the A (FeIII-O2•-/CuI/Tyr) → PM (FeIV=O/CuII-OH/Tyr•) step. In this review, we have focused on the recent advancements in the design, development, and characterization of synthetic heme-peroxo‑copper model complexes, which can circumvent the abovementioned limitation, for the investigation of the formation of IP and its O-O cleavage chemistry. Novel findings regarding (a) proton and electron transfer (PT/ET) processes, together with their contributions to exogenous phenol induced O-O cleavage, (b) the stereo-electronic tunability of the secondary coordination sphere (especially hydrogen-bonding) on the geometric and spin state alteration of the heme-peroxo‑copper unit, and (c) a plausible mechanism for the Tyr-His cofactor biogenesis, are discussed in great detail. Additionally, since the ferric-superoxide and the ferryl-oxo (Compound II) species are critically involved in the CcO catalytic cycle, this review also highlights a few fundamental aspects of these heme-only (i.e., without copper) species, including the structural and reactivity influences of electron-donating trans-axial ligands and Lewis acid-promoted H-bonding.
Collapse
Affiliation(s)
- Sanjib Panda
- Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Hai Phan
- Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Kenneth D Karlin
- Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA.
| |
Collapse
|
3
|
Jose A, Schaefer AW, Roveda AC, Transue WJ, Choi SK, Ding Z, Gennis RB, Solomon EI. The three-spin intermediate at the O-O cleavage and proton-pumping junction in heme-Cu oxidases. Science 2021; 373:1225-1229. [PMID: 34516790 DOI: 10.1126/science.abh3209] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
[Figure: see text].
Collapse
Affiliation(s)
- Anex Jose
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Andrew W Schaefer
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Antonio C Roveda
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Wesley J Transue
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Sylvia K Choi
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
| | - Ziqiao Ding
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
| | - Robert B Gennis
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
| | - Edward I Solomon
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA.,Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025, USA
| |
Collapse
|
4
|
Zheng D, Yuan XA, Ma H, Li X, Wang X, Liu Z, Ma J. Unexpected solvent effects on the UV/Vis absorption spectra of o-cresol in toluene and benzene: in contrast with non-aromatic solvents. ROYAL SOCIETY OPEN SCIENCE 2018; 5:171928. [PMID: 29657794 PMCID: PMC5882718 DOI: 10.1098/rsos.171928] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 02/09/2018] [Indexed: 06/07/2023]
Abstract
Cresol is a prototype molecule in understanding intermolecular interactions in material and biological systems, because it offers different binding sites with various solvents and protonation states under different pH values. It is found that the UV/Vis absorption spectra of o-cresol in aromatic solvents (benzene, toluene) are characterized by a sharp peak, unlike the broad double-peaks in 11 non-aromatic solvents. Both molecular dynamics simulations and electronic structure calculations revealed the formation of intermolecular π-complexation between o-cresol and aromatic solvents. The thermal movements of solvent and solute molecules render the conformations of o-cresol changing between trans and cis isomers. The π-interaction makes the cis configuration a dominant isomer, hence leading to the single keen-edged UV/Vis absorption peak at approximately 283 nm. The free conformation changes between trans and cis in aqueous solution rationalize the broader absorption peaks in the range of 260-280 nm. The pH dependence of the UV/Vis absorption spectra in aqueous solutions is also rationalized by different protonation states of o-cresol. The explicit solvent model with long-ranged interactions is vital to describe the effects of π-complexation and electrostatic interaction on the UV/Vis absorption spectra of o-cresol in toluene and alkaline aqueous (pH > 10.3) solutions, respectively.
Collapse
Affiliation(s)
| | | | | | | | | | | | - Jing Ma
- Author for correspondence: Jing Ma e-mail:
| |
Collapse
|
5
|
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]
|
6
|
Choi J, Yang C, Fujitsuka M, Tojo S, Ihee H, Majima T. Reply to “Comment on ‘Proton Transfer of Guanine Radical Cations Studied by Time-Resolved Resonance Raman Spectroscopy Combined with Pulse Radiolysis’”. J Phys Chem B 2016. [DOI: 10.1021/acs.jpcb.6b00713] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jungkweon Choi
- The
Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
- Center
for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 305-701, Republic of Korea
| | - Cheolhee Yang
- Center
for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 305-701, Republic of Korea
- Department
of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Republic of Korea
| | - Mamoru Fujitsuka
- The
Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Sachiko Tojo
- The
Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Hyotcherl Ihee
- Center
for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 305-701, Republic of Korea
- Department
of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Republic of Korea
| | - Tetsuro Majima
- The
Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| |
Collapse
|
7
|
Yu Y, Cui C, Liu X, Petrik ID, Wang J, Lu Y. A Designed Metalloenzyme Achieving the Catalytic Rate of a Native Enzyme. J Am Chem Soc 2015; 137:11570-3. [PMID: 26318313 PMCID: PMC4676421 DOI: 10.1021/jacs.5b07119] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Terminal
oxidases catalyze four-electron reduction of oxygen to
water, and the energy harvested is utilized to drive the synthesis
of adenosine triphosphate. While much effort has been made to design
a catalyst mimicking the function of terminal oxidases, most biomimetic
catalysts have much lower activity than native oxidases. Herein we
report a designed oxidase in myoglobin with an O2 reduction
rate (52 s–1) comparable to that of a native cytochrome
(cyt) cbb3 oxidase (50 s–1) under identical conditions. We achieved this goal by engineering
more favorable electrostatic interactions between a functional oxidase
model designed in sperm whale myoglobin and its native redox partner,
cyt b5, resulting in a 400-fold electron
transfer (ET) rate enhancement. Achieving high activity equivalent
to that of native enzymes in a designed metalloenzyme offers deeper
insight into the roles of tunable processes such as ET in oxidase
activity and enzymatic function and may extend into applications such
as more efficient oxygen reduction reaction catalysts for biofuel
cells.
Collapse
Affiliation(s)
| | | | - Xiaohong Liu
- Laboratory of Non-coding RNA, Institute of Biophysics, Chinese Academy of Sciences , 15 Datun Road, Chaoyang District, Beijing 100101, P. R. China
| | | | - Jiangyun Wang
- Laboratory of Non-coding RNA, Institute of Biophysics, Chinese Academy of Sciences , 15 Datun Road, Chaoyang District, Beijing 100101, P. R. China
| | | |
Collapse
|
8
|
Yu Y, Lv X, Li J, Zhou Q, Cui C, Hosseinzadeh P, Mukherjee A, Nilges MJ, Wang J, Lu Y. Defining the role of tyrosine and rational tuning of oxidase activity by genetic incorporation of unnatural tyrosine analogs. J Am Chem Soc 2015; 137:4594-7. [PMID: 25672571 PMCID: PMC4676419 DOI: 10.1021/ja5109936] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Indexed: 12/31/2022]
Abstract
While a conserved tyrosine (Tyr) is found in oxidases, the roles of phenol ring pKa and reduction potential in O2 reduction have not been defined despite many years of research on numerous oxidases and their models. These issues represent major challenges in our understanding of O2 reduction mechanism in bioenergetics. Through genetic incorporation of unnatural amino acid analogs of Tyr, with progressively decreasing pKa of the phenol ring and increasing reduction potential, in the active site of a functional model of oxidase in myoglobin, a linear dependence of both the O2 reduction activity and the fraction of H2O formation with the pKa of the phenol ring has been established. By using these unnatural amino acids as spectroscopic probe, we have provided conclusive evidence for the location of a Tyr radical generated during reaction with H2O2, by the distinctive hyperfine splitting patterns of the halogenated tyrosines and one of its deuterated derivatives incorporated at the 33 position of the protein. These results demonstrate for the first time that enhancing the proton donation ability of the Tyr enhances the oxidase activity, allowing the Tyr analogs to augment enzymatic activity beyond that of natural Tyr.
Collapse
Affiliation(s)
- Yang Yu
- Center of Biophysics and Computational Biology, Department of Chemistry, Department of Biochemistry, Illinois EPR Research
Center, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Xiaoxuan Lv
- Laboratory
of Non-Coding RNA, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing, 100101, P. R. China
- University of Chinese
Academy of Sciences, Beijing 100049, P. R. China
| | - Jiasong Li
- Laboratory
of Non-Coding RNA, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing, 100101, P. R. China
- University of Chinese
Academy of Sciences, Beijing 100049, P. R. China
| | - Qing Zhou
- Laboratory
of Non-Coding RNA, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing, 100101, P. R. China
- University of Chinese
Academy of Sciences, Beijing 100049, P. R. China
| | - Chang Cui
- Center of Biophysics and Computational Biology, Department of Chemistry, Department of Biochemistry, Illinois EPR Research
Center, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Parisa Hosseinzadeh
- Center of Biophysics and Computational Biology, Department of Chemistry, Department of Biochemistry, Illinois EPR Research
Center, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Arnab Mukherjee
- Center of Biophysics and Computational Biology, Department of Chemistry, Department of Biochemistry, Illinois EPR Research
Center, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Mark J. Nilges
- Center of Biophysics and Computational Biology, Department of Chemistry, Department of Biochemistry, Illinois EPR Research
Center, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Jiangyun Wang
- Laboratory
of Non-Coding RNA, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing, 100101, P. R. China
- University of Chinese
Academy of Sciences, Beijing 100049, P. R. China
| | - Yi Lu
- Center of Biophysics and Computational Biology, Department of Chemistry, Department of Biochemistry, Illinois EPR Research
Center, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| |
Collapse
|
9
|
Solomon EI, Heppner DE, Johnston EM, Ginsbach JW, Cirera J, Qayyum M, Kieber-Emmons MT, Kjaergaard CH, Hadt RG, Tian L. Copper active sites in biology. Chem Rev 2014; 114:3659-853. [PMID: 24588098 PMCID: PMC4040215 DOI: 10.1021/cr400327t] [Citation(s) in RCA: 1135] [Impact Index Per Article: 113.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
| | - David E. Heppner
- Department of Chemistry, Stanford University, Stanford, CA, 94305
| | | | - Jake W. Ginsbach
- Department of Chemistry, Stanford University, Stanford, CA, 94305
| | - Jordi Cirera
- Department of Chemistry, Stanford University, Stanford, CA, 94305
| | - Munzarin Qayyum
- Department of Chemistry, Stanford University, Stanford, CA, 94305
| | | | | | - Ryan G. Hadt
- Department of Chemistry, Stanford University, Stanford, CA, 94305
| | - Li Tian
- Department of Chemistry, Stanford University, Stanford, CA, 94305
| |
Collapse
|
10
|
Yu Y, Mukherjee A, Nilges MJ, Hosseinzadeh P, Miner KD, Lu Y. Direct EPR observation of a tyrosyl radical in a functional oxidase model in myoglobin during both H2O2 and O2 reactions. J Am Chem Soc 2014; 136:1174-1177. [PMID: 24383850 PMCID: PMC3955430 DOI: 10.1021/ja4091885] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tyrosine is a conserved redox-active amino acid that plays important roles in heme-copper oxidases (HCO). Despite the widely proposed mechanism that involves a tyrosyl radical, its direct observation under O2 reduction conditions remains elusive. Using a functional oxidase model in myoglobin called F33Y-Cu(B)Mb that contains an engineered tyrosine, we report herein direct observation of a tyrosyl radical during both reactions of H2O2 with oxidized protein and O2 with reduced protein by electron paramagnetic resonance spectroscopy, providing a firm support for the tyrosyl radical in the HCO enzymatic mechanism.
Collapse
Affiliation(s)
- Yang Yu
- Center for Biophysics and Computational Biology, University of Illinois at Urbana–Champaign, Urbana, Illinois 61801, United States
| | - Arnab Mukherjee
- Department of Chemistry, University of Illinois at Urbana–Champaign, Urbana, Illinois 61801, United States
| | - Mark J. Nilges
- The Illinois EPR Research Center, University of Illinois at Urbana–Champaign, Urbana, Illinois 61801, United States
| | - Parisa Hosseinzadeh
- Department of Biochemistry, University of Illinois at Urbana–Champaign, Urbana, Illinois 61801, United States
| | - Kyle D. Miner
- Department of Biochemistry, University of Illinois at Urbana–Champaign, Urbana, Illinois 61801, United States
| | - Yi Lu
- Center for Biophysics and Computational Biology, University of Illinois at Urbana–Champaign, Urbana, Illinois 61801, United States
- Department of Chemistry, University of Illinois at Urbana–Champaign, Urbana, Illinois 61801, United States
- Department of Biochemistry, University of Illinois at Urbana–Champaign, Urbana, Illinois 61801, United States
| |
Collapse
|
11
|
Massaad J, Micheau JC, Coudret C, Serpentini CL, Guirado G. Proton Catalysis in the Redox Responsivity of a Mini-Sized Photochromic Diarylethene. Chemistry 2013; 19:12435-45. [DOI: 10.1002/chem.201301566] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Indexed: 11/08/2022]
Affiliation(s)
- Julie Massaad
- Université Paul Sabatier, UMR CNRS 5623, IMRCP, 31062 Toulouse (France)
| | | | | | | | | |
Collapse
|
12
|
Yu MA, Egawa T, Shinzawa-Itoh K, Yoshikawa S, Guallar V, Yeh SR, Rousseau DL, Gerfen GJ. Two tyrosyl radicals stabilize high oxidation states in cytochrome C oxidase for efficient energy conservation and proton translocation. J Am Chem Soc 2012; 134:4753-61. [PMID: 22296274 DOI: 10.1021/ja210535w] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The reaction of oxidized bovine cytochrome c oxidase (bCcO) with hydrogen peroxide (H(2)O(2)) was studied by electron paramagnetic resonance (EPR) to determine the properties of radical intermediates. Two distinct radicals with widths of 12 and 46 G are directly observed by X-band EPR in the reaction of bCcO with H(2)O(2) at pH 6 and pH 8. High-frequency EPR (D-band) provides assignments to tyrosine for both radicals based on well-resolved g-tensors. The wide radical (46 G) exhibits g-values similar to a radical generated on L-Tyr by UV-irradiation and to tyrosyl radicals identified in many other enzyme systems. In contrast, the g-values of the narrow radical (12 G) deviate from L-Tyr in a trend akin to the radicals on tyrosines with substitutions at the ortho position. X-band EPR demonstrates that the two tyrosyl radicals differ in the orientation of their β-methylene protons. The 12 G wide radical has minimal hyperfine structure and can be fit using parameters unique to the post-translationally modified Y244 in bCcO. The 46 G wide radical has extensive hyperfine structure and can be fit with parameters consistent with Y129. The results are supported by mixed quantum mechanics and molecular mechanics calculations. In addition to providing spectroscopic evidence of a radical formed on the post-translationally modified tyrosine in CcO, this study resolves the much debated controversy of whether the wide radical seen at low pH in the bovine enzyme is a tyrosine or tryptophan. The possible role of radical formation and migration in proton translocation is discussed.
Collapse
Affiliation(s)
- Michelle A Yu
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, United States
| | | | | | | | | | | | | | | |
Collapse
|
13
|
Voicescu M, El Khoury Y, Martel D, Heinrich M, Hellwig P. Spectroscopic Analysis of Tyrosine Derivatives: On the Role of the Tyrosine−Histidine Covalent Linkage in Cytochrome c Oxidase. J Phys Chem B 2009; 113:13429-36. [DOI: 10.1021/jp9048742] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mariana Voicescu
- Laboratoire de Spectroscopie Vibrationnelle et Electrochimie des Biomolécules, UMR 7177, Institut de Chimie, CNRS-Université de Strasbourg, 1 rue Blaise Pascal, 67070 Strasbourg, France, and Laboratoire d’Electrochimie et de Chimie Physique du Corps Solide, Institut de Chimie, UMR 7177 CNRS, Université de Strasbourg, 4 rue Blaise Pascal, 67070 Strasbourg, France
| | - Youssef El Khoury
- Laboratoire de Spectroscopie Vibrationnelle et Electrochimie des Biomolécules, UMR 7177, Institut de Chimie, CNRS-Université de Strasbourg, 1 rue Blaise Pascal, 67070 Strasbourg, France, and Laboratoire d’Electrochimie et de Chimie Physique du Corps Solide, Institut de Chimie, UMR 7177 CNRS, Université de Strasbourg, 4 rue Blaise Pascal, 67070 Strasbourg, France
| | - David Martel
- Laboratoire de Spectroscopie Vibrationnelle et Electrochimie des Biomolécules, UMR 7177, Institut de Chimie, CNRS-Université de Strasbourg, 1 rue Blaise Pascal, 67070 Strasbourg, France, and Laboratoire d’Electrochimie et de Chimie Physique du Corps Solide, Institut de Chimie, UMR 7177 CNRS, Université de Strasbourg, 4 rue Blaise Pascal, 67070 Strasbourg, France
| | - Martine Heinrich
- Laboratoire de Spectroscopie Vibrationnelle et Electrochimie des Biomolécules, UMR 7177, Institut de Chimie, CNRS-Université de Strasbourg, 1 rue Blaise Pascal, 67070 Strasbourg, France, and Laboratoire d’Electrochimie et de Chimie Physique du Corps Solide, Institut de Chimie, UMR 7177 CNRS, Université de Strasbourg, 4 rue Blaise Pascal, 67070 Strasbourg, France
| | - Petra Hellwig
- Laboratoire de Spectroscopie Vibrationnelle et Electrochimie des Biomolécules, UMR 7177, Institut de Chimie, CNRS-Université de Strasbourg, 1 rue Blaise Pascal, 67070 Strasbourg, France, and Laboratoire d’Electrochimie et de Chimie Physique du Corps Solide, Institut de Chimie, UMR 7177 CNRS, Université de Strasbourg, 4 rue Blaise Pascal, 67070 Strasbourg, France
| |
Collapse
|
14
|
Offenbacher A, White KN, Sen I, Oliver AG, Konopelski JP, Barry BA, Einarsdóttir O. A spectroscopic investigation of a tridentate Cu-complex mimicking the tyrosine-histidine cross-link of cytochrome C oxidase. J Phys Chem B 2009; 113:7407-17. [PMID: 19438285 DOI: 10.1021/jp9010795] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Heme-copper oxidases have a crucial role in the energy transduction mechanism, catalyzing the reduction of dioxygen to water. The reduction of dioxygen takes place at the binuclear center, which contains heme a3 and CuB. The X-ray crystal structures have revealed that the C6' of tyrosine 244 (bovine heart numbering) is cross-linked to a nitrogen of histidine 240, a ligand to CuB. The role of the cross-linked tyrosine at the active site still remains unclear. In order to provide insight into the function of the cross-linked tyrosine, we have investigated the spectroscopic and electrochemical properties of chemical analogues of the CuB-His-Tyr site. The analogues, a tridentate histidine-phenol cross-linked ether ligand and the corresponding Cu-containing complex, were previously synthesized in our laboratory (White, K.; et al. Chem. Commun. 2007, 3252-3254). Spectrophotometric titrations of the ligand and the Cu-complex indicate a pKa of the phenolic proton of 8.8 and 7.7, respectively. These results are consistent with the cross-linked tyrosine playing a proton delivery role at the cytochrome c oxidase active site. The presence of the phenoxyl radical was investigated at low temperature using electron paramagnetic resonance (EPR) and Fourier transform infrared (FT-IR) difference spectroscopy. UV photolysis of the ligand, without bound copper, generated a narrow g=2.0047 signal, attributed to the phenoxyl radial. EPR spectra recorded before and after UV photolysis of the Cu-complex showed a g=2 signal characteristic of oxidized copper, suggesting that the copper is not spin-coupled to the phenoxyl radical. An EPR signal from the phenoxyl radical was not observed in the Cu-complex, either due to spin relaxation of the two unpaired electrons or to masking of the narrow phenoxyl radical signal by the strong copper contribution. Stable isotope (13C) labeling of the phenol ring (C1') Cu-complex, combined with photoinduced difference FT-IR spectroscopy, revealed bands at 1485 and 1483 cm(-1) in the 12C-minus-13C-isotope-edited spectra of the ligand and Cu-complex, respectively. These bands are attributed to the radical v7a stretching frequency and are shifted to 1468 and 1472 cm(-1), respectively, with 13C1' labeling. These results show that a radical is generated in both the ligand and the Cu-complex and support the unambiguous assignment of a vibrational band to the phenoxyl radical v7a stretching mode. These data are discussed with respect to a possible role of the cross-linked tyrosine radical in cytochrome c oxidase.
Collapse
Affiliation(s)
- Adam Offenbacher
- Department of Chemistry and Biochemistry and the Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | | | | | | | | | | | | |
Collapse
|
15
|
Collman JP, Decréau RA. Functional biomimetic models for the active site in the respiratory enzyme cytochrome c oxidase. Chem Commun (Camb) 2008:5065-76. [PMID: 18956030 DOI: 10.1039/b808070b] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A functional analog of the active site in the respiratory enzyme, cytochrome c oxidase (CcO) reproduces every feature in CcO's active site: a myoglobin-like heme (heme a3), a distal tridentate imidazole copper complex (Cu(B)), a phenol (Tyr244), and a proximal imidazole. When covalently attached to a liquid-crystalline SAM film on an Au electrode, this functional model continuously catalyzes the selective four-electron reduction of dioxygen at physiological potential and pH, under rate-limiting electron flux (as occurs in CcO).
Collapse
Affiliation(s)
- James P Collman
- Stanford University, Chemistry Department, Stanford, CA-94305-5080, USA.
| | | |
Collapse
|
16
|
Milko P, Roithová J, Tsierkezos N, Schröder D. The C-O stretch as an unprecedently large spectral marker for the electron transfer between Copper(II) and a phenolate anion. J Am Chem Soc 2008; 130:7186-7. [PMID: 18479087 DOI: 10.1021/ja801079r] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
An unprecedented red shift of more than 200 cm(-1) in the vibrational frequency of the C-O bond in the [Cu(PhO)Ln]+ complex (PhO = phenoxy), dependent on the number n of additional ligands L, is reported. Upon change of n from 1 to 2, the spin density is shifted from the aromatic ring to the oxygen and copper atoms, which is reflected in the bond order and thus vibrational frequency of the C-O bond.
Collapse
Affiliation(s)
- Petr Milko
- Faculty of Science, Department of Organic Chemistry, Charles University in Prague, Hlavova 8, 12843 Prague 2, Czech Republic
| | | | | | | |
Collapse
|
17
|
Daskalakis V, Pinakoulaki E, Stavrakis S, Varotsis C. Probing the Environment of CuB in Heme−Copper Oxidases. J Phys Chem B 2007; 111:10502-9. [PMID: 17696387 DOI: 10.1021/jp0718597] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Time-resolved step-scan FTIR (TRS2-FTIR) and density functional theory have been applied to probe the structural dynamics of CuB in heme-copper oxidases at room temperature. The TRS2-FTIR data of cbb3 from Pseudomonas stutzeri indicate a small variation in the frequency of the transient CO bound to CuB in the pH/pD 7-9 range. This observation in conjunction with density functional theory calculations, in which significant frequency shifts of the nu(CO) are observed upon deprotonation and/or detachment of the CuB ligands, demonstrates that the properties of the CuB ligands including the cross-linked tyrosine, in contrast to previous reports, remain unchanged in the pH 7-9 range. We attribute the small variations in the nu(CO) of CuB to protein conformational changes in the vicinity of CuB. Consequently, the split of the heme Fe-CO vibrations (alpha-, beta-, and gamma-forms) is not due to changes in the ligation and/or protonation states of the CuB ligands or to the presence of one or more ionizable groups, as previously suggested, but the result of global protein conformational changes in the vicinity of CuB which, in turn, affect the position of CuB with respect to the heme Fe.
Collapse
Affiliation(s)
- Vangelis Daskalakis
- Department of Chemistry, University of Crete, 71003 Voutes, Heraklion, Crete, Greece
| | | | | | | |
Collapse
|
18
|
Liu JG, Naruta Y, Tani F. Synthetic Models of the Active Site of Cytochromec Oxidase: Influence of Tridentate or Tetradentate Copper Chelates Bearing a HisTyr Linkage Mimic on Dioxygen Adduct Formation by Heme/Cu Complexes. Chemistry 2007; 13:6365-78. [PMID: 17503416 DOI: 10.1002/chem.200601884] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Two synthetic models of the active site of cytochrome c oxidase--[(LN4-OH)CuI-FeII(TMP)]+ (1 a) and [(LN3-OH)CuI-FeII(TMP)]+ (2 a)-have been designed and synthesized. These models each contain a heme and a covalently attached copper moiety supported either by a tetradentate N4-copper chelate or by a tridentate N3-copper chelate including a moiety that acts as a mimic of the crosslinked His-Tyr component of cytochrome c oxidase. Low-temperature oxygenation reactions of these models have been investigated by spectroscopic methods including UV/Vis, resonance Raman, ESI-MS, and EPR spectroscopy. Oxygenation of the tetradentate model 1 a in MeCN and in other solvents produces a low-temperature-stable dioxygen-bridged peroxide [(LN4-OH)CuII-O2-FeIII(TMP)]+ {nuO--O=799 (16O2)/752 cm(-1) (18O2)}, while a heme superoxide species [(TMP)FeIII(O2-)CuIILN3-OH] {nuFe--O2: 576 (16O2)/551 cm(-1) (18O2)} is generated when the tridentate model 2 a is oxygenated in EtCN solution under similar experimental conditions. The coexistence of a heme superoxide species [(TMP)FeIII(O2-)CuIILN3-OH] and a bridged peroxide [(LN3-OH)CuII-O2-FeIII(TMP)]+ species in equal amounts is observed when the oxygenation reaction of 2 a is performed in CH2Cl(2)/7 % EtCN, while the percentage of the peroxide (approximately 70 %) in relation to superoxide (approximately 30 %) increases further when the crosslinked phenol moiety in 2 a is deprotonated to produce the bridged peroxide [(LN3-OH)CuII-O2-FeIII(TMP)]+ {nuO--O: 812 (16O2)/765 cm(-1) (18O2)} as the main dioxygen intermediate. The weak reducibility and decreased O2 reactivity of the tricoordinated CuI site in 2 a are responsible for the solvent-dependent formation of dioxygen adducts. The initial binding of dioxygen to the copper site en route to the formation of a bridged heme-O2-Cu intermediate by model 2 a is suggested and the deprotonated crosslinked His-Tyr moiety might contribute to enhancement of the O2 affinity of the CuI site at an early stage of the dioxygen-binding process.
Collapse
Affiliation(s)
- Jin-Gang Liu
- Institute for Materials Chemistry and Engineering, Kyushu University, Higashi-ku, Fukuoka, 812-8581, Japan
| | | | | |
Collapse
|
19
|
Chufán EE, Puiu SC, Karlin KD. Heme-copper/dioxygen adduct formation, properties, and reactivity. Acc Chem Res 2007; 40:563-72. [PMID: 17550225 DOI: 10.1021/ar700031t] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This Account focuses on our recent developments in synthetic heme/copper/O 2 chemistry, potentially relevant to the mechanism of action of heme-copper oxidases (e.g., cytochrome c oxidase) and to dioxygen activation chemistry. Methods for the generation of O 2 adducts, which are high-spin heme(Fe (III))-peroxo-Cu (II) complexes, are described, along with a detailed structural/electronic characterization of one example. The coordination mode of the O 2-derived heme-Cu bridging group depends upon the copper-ligand environment, resulting in micro-(O 2 (2-)) side-on to Fe (III) and end-on to Cu (II) (micro-eta (2):eta (1)) binding for cases having N 4 tetradentate ligands but side-on/side-on (micro-eta (2):eta (2)) micro-peroxo coordination with tridentate copper chelates. The dynamics of the generation of Fe (III)-(O 2 (2-))-Cu (II) complexes are known in some cases, including the initial formation of a short-lived superoxo (heme)Fe (III)(O 2 -) intermediate. Complexes with cross-linked imidazole-phenol "cofactors" adjacent to the copper centers have also been described. Essential investigations of heme-copper-mediated reductive O-O bond cleavage chemistry are ongoing.
Collapse
Affiliation(s)
- Eduardo E Chufán
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | | | | |
Collapse
|
20
|
Collman JP, Decréau RA, Yan Y, Yoon J, Solomon EI. Intramolecular single-turnover reaction in a cytochrome C oxidase model bearing a Tyr244 mimic. J Am Chem Soc 2007; 129:5794-5. [PMID: 17429972 PMCID: PMC2512969 DOI: 10.1021/ja0690969] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- James P Collman
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA.
| | | | | | | | | |
Collapse
|
21
|
Lonnon DG, Lee ST, Colbran SB. Valence Tautomerism and Coordinative Lability in Copper(II)−Imidazolyl−Semiquinonate Anion Radical Models for the CuB Center in Cytochrome c Oxidases. J Am Chem Soc 2007; 129:5800-1. [PMID: 17429970 DOI: 10.1021/ja068972f] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- David G Lonnon
- School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia
| | | | | |
Collapse
|
22
|
White KN, Sen I, Szundi I, Landaverry YR, Bria LE, Konopelski JP, Olmstead MM, Einarsdóttir O. Synthesis and structural characterization of cross-linked histidine–phenol Cu(ii) complexes as cytochrome c oxidase active site models. Chem Commun (Camb) 2007:3252-4. [PMID: 17668091 DOI: 10.1039/b703835f] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Tridentate cross-linked histidine-phenol Cu(ii) ether and ester complexes, chemical analogs of the active site of several heme-copper oxidases, have been synthesized and crystallized.
Collapse
Affiliation(s)
- Kimberly N White
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA
| | | | | | | | | | | | | | | |
Collapse
|