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Borgstahl G, Azadmanesh J, Slobodnik K, Struble L, Cone E, Dasgupta M, Lutz W, Kumar S, Natarajan A, Coates L, Weiss K, Myles D, Kroll T. The role of Tyr34 in proton-coupled electron transfer of human manganese superoxide dismutase. RESEARCH SQUARE 2024:rs.3.rs-4494128. [PMID: 38946943 PMCID: PMC11213228 DOI: 10.21203/rs.3.rs-4494128/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Human manganese superoxide dismutase (MnSOD) plays a crucial role in controlling levels of reactive oxygen species (ROS) by converting superoxide (O2 ●-) to molecular oxygen (O2) and hydrogen peroxide (H2O2) with proton-coupled electron transfers (PCETs). The reactivity of human MnSOD is determined by the state of a key catalytic residue, Tyr34, that becomes post-translationally inactivated by nitration in various diseases associated with mitochondrial dysfunction. We previously reported that Tyr34 has an unusual pKa due to its proximity to the Mn metal and undergoes cyclic deprotonation and protonation events to promote the electron transfers of MnSOD. To shed light on the role of Tyr34 MnSOD catalysis, we performed neutron diffraction, X-ray spectroscopy, and quantum chemistry calculations of Tyr34Phe MnSOD in various enzymatic states. The data identifies the contributions of Tyr34 in MnSOD activity that support mitochondrial function and presents a thorough characterization of how a single tyrosine modulates PCET catalysis.
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Azadmanesh J, Slobodnik K, Struble LR, Cone EA, Dasgupta M, Lutz WE, Kumar S, Natarajan A, Coates L, Weiss KL, Myles DAA, Kroll T, Borgstahl GEO. The role of Tyr34 in proton-coupled electron transfer of human manganese superoxide dismutase. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.29.596464. [PMID: 38853997 PMCID: PMC11160768 DOI: 10.1101/2024.05.29.596464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Human manganese superoxide dismutase (MnSOD) plays a crucial role in controlling levels of reactive oxygen species (ROS) by converting superoxide (O 2 •- ) to molecular oxygen (O 2 ) and hydrogen peroxide (H 2 O 2 ) with proton-coupled electron transfers (PCETs). The reactivity of human MnSOD is determined by the state of a key catalytic residue, Tyr34, that becomes post-translationally inactivated by nitration in various diseases associated with mitochondrial dysfunction. We previously reported that Tyr34 has an unusual pK a due to its proximity to the Mn metal and undergoes cyclic deprotonation and protonation events to promote the electron transfers of MnSOD. To shed light on the role of Tyr34 MnSOD catalysis, we performed neutron diffraction, X-ray spectroscopy, and quantum chemistry calculations of Tyr34Phe MnSOD in various enzymatic states. The data identifies the contributions of Tyr34 in MnSOD activity that support mitochondrial function and presents a thorough characterization of how a single tyrosine modulates PCET catalysis.
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Borgstahl G, Azadmanesh J, Slobodnik K, Struble L, Lutz W, Coates L, Weiss K, Myles D, Kroll T. Revealing the atomic and electronic mechanism of human manganese superoxide dismutase product inhibition. RESEARCH SQUARE 2024:rs.3.rs-3880128. [PMID: 38405788 PMCID: PMC10889052 DOI: 10.21203/rs.3.rs-3880128/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Human manganese superoxide dismutase (MnSOD) is a crucial oxidoreductase that maintains the vitality of mitochondria by converting O 2 ∙ - to O 2 and H 2 O 2 with proton-coupled electron transfers (PCETs). Since changes in mitochondrial H 2 O 2 concentrations are capable of stimulating apoptotic signaling pathways, human MnSOD has evolutionarily gained the ability to be highly inhibited by its own product, H 2 O 2 . A separate set of PCETs is thought to regulate product inhibition, though mechanisms of PCETs are typically unknown due to difficulties in detecting the protonation states of specific residues that coincide with the electronic state of the redox center. To shed light on the underlying mechanism, we combined neutron diffraction and X-ray absorption spectroscopy of the product-bound, trivalent, and divalent states to reveal the all-atom structures and electronic configuration of the metal. The data identifies the product-inhibited complex for the first time and a PCET mechanism of inhibition is constructed.
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Azadmanesh J, Slobodnik K, Struble LR, Lutz WE, Coates L, Weiss KL, Myles DAA, Kroll T, Borgstahl GEO. Revealing the atomic and electronic mechanism of human manganese superoxide dismutase product inhibition. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.26.577433. [PMID: 38328249 PMCID: PMC10849630 DOI: 10.1101/2024.01.26.577433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Human manganese superoxide dismutase (MnSOD) is a crucial oxidoreductase that maintains the vitality of mitochondria by converting O 2 ●- to O 2 and H 2 O 2 with proton-coupled electron transfers (PCETs). Since changes in mitochondrial H 2 O 2 concentrations are capable of stimulating apoptotic signaling pathways, human MnSOD has evolutionarily gained the ability to be highly inhibited by its own product, H 2 O 2 . A separate set of PCETs is thought to regulate product inhibition, though mechanisms of PCETs are typically unknown due to difficulties in detecting the protonation states of specific residues that coincide with the electronic state of the redox center. To shed light on the underlying mechanism, we combined neutron diffraction and X-ray absorption spectroscopy of the product-bound, trivalent, and divalent states to reveal the all-atom structures and electronic configuration of the metal. The data identifies the product-inhibited complex for the first time and a PCET mechanism of inhibition is constructed.
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da Silva MAR, Tarakina NV, Filho JBG, Cunha CS, Rocha GFSR, Diab GAA, Ando RA, Savateev O, Agirrezabal-Telleria I, Silva IF, Stolfi S, Ghigna P, Fagnoni M, Ravelli D, Torelli P, Braglia L, Teixeira IF. Single-Atoms on Crystalline Carbon Nitrides for Selective C─H Photooxidation: A Bridge to Achieve Homogeneous Pathways in Heterogeneous Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2304152. [PMID: 37986204 DOI: 10.1002/adma.202304152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 09/15/2023] [Indexed: 11/22/2023]
Abstract
Single-atom catalysis is a field of paramount importance in contemporary science due to its exceptional ability to combine the domains of homogeneous and heterogeneous catalysis. Iron and manganese metalloenzymes are known to be effective in C─H oxidation reactions in nature, inspiring scientists to mimic their active sites in artificial catalytic systems. Herein, a simple and versatile cation exchange method is successfully employed to stabilize low-cost iron and manganese single-atoms in poly(heptazine imides) (PHI). The resulting materials are employed as photocatalysts for toluene oxidation, demonstrating remarkable selectivity toward benzaldehyde. The protocol is then extended to the selective oxidation of different substrates, including (substituted) alkylaromatics, benzyl alcohols, and sulfides. Detailed mechanistic investigations revealed that iron- and manganese-containing photocatalysts work through a similar mechanism via the formation of high-valent M═O species. Operando X-ray absorption spectroscopy (XAS) is employed to confirm the formation of high-valent iron- and manganese-oxo species, typically found in metalloenzymes involved in highly selective C─H oxidations.
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Affiliation(s)
- Marcos A R da Silva
- Department of Chemistry, Federal University of São Carlos, São Carlos, São Paulo, 13565-905, Brazil
| | - Nadezda V Tarakina
- Department of Colloid Chemistry, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, D-14476, Potsdam, Germany
| | - José B G Filho
- Department of Chemistry, ICEx, Federal University of Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil
| | - Carla S Cunha
- Department of Chemistry, Federal University of São Carlos, São Carlos, São Paulo, 13565-905, Brazil
| | - Guilherme F S R Rocha
- Department of Chemistry, Federal University of São Carlos, São Carlos, São Paulo, 13565-905, Brazil
| | - Gabriel A A Diab
- Department of Chemistry, Federal University of São Carlos, São Carlos, São Paulo, 13565-905, Brazil
| | - Rômulo Augusto Ando
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes, 748, São Paulo, 05508-000, Brazil
| | - Oleksandr Savateev
- Department of Colloid Chemistry, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, D-14476, Potsdam, Germany
| | - Iker Agirrezabal-Telleria
- Department of Chemical and Environmental Engineering of the Bilbao Engineering School, University of Basque Country (UPV/EHU), Plaza Torres Quevedo 1, Bilbao, 48013, Spain
| | - Ingrid F Silva
- Department of Colloid Chemistry, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, D-14476, Potsdam, Germany
| | - Sara Stolfi
- Department of Chemistry, University of Pavia, viale Taramelli 12, Pavia, 27100, Italy
| | - Paolo Ghigna
- Department of Chemistry, University of Pavia, viale Taramelli 12, Pavia, 27100, Italy
| | - Maurizio Fagnoni
- Department of Chemistry, University of Pavia, viale Taramelli 12, Pavia, 27100, Italy
| | - Davide Ravelli
- Department of Chemistry, University of Pavia, viale Taramelli 12, Pavia, 27100, Italy
| | - Piero Torelli
- TASC Laboratory, CNR-IOM, Istituto Officina dei Materiali, Trieste, 34149, Italy
| | - Luca Braglia
- TASC Laboratory, CNR-IOM, Istituto Officina dei Materiali, Trieste, 34149, Italy
| | - Ivo F Teixeira
- Department of Chemistry, Federal University of São Carlos, São Carlos, São Paulo, 13565-905, Brazil
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