Article
Biochemistry & Molecular Biology
Victor N. Nemykin, Jared R. Sabin, Brian W. Kail, Anup Upadhyay, Michael P. Hendrich, Partha Basu
Summary: The EPR investigation of mononuclear cis- and trans-(L1O)MoOCl2 complexes reveals a difference in their spin Hamiltonian parameters due to the different ligand fields created by the heteroscorpionate donor atoms. DFT calculations were used to determine the values and orientations of the g and A tensors in various isomeric mononuclear oxo-molybdenum(V) complexes. The results showed that the use of a hybrid exchange-correlation functional with 25% of the Hartree-Fock exchange provided the best agreement between theory and experiment. The influence of ligand fields on the energies and contributions of molybdenum d orbitals to the g and A tensors and their relative orientations were analyzed using a simplified ligand-field approach.
JOURNAL OF INORGANIC BIOCHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Roland Weindl, Rachit Khare, Libor Kovarik, Andreas Jentys, Karsten Reuter, Hui Shi, Johannes A. Lercher
Summary: Supercages of FAU-type zeolites provide a robust scaffold for stabilizing molybdenum sulfide clusters, leading to stable catalytic activity for ethene hydrogenation. The Mo4S4 clusters trapped within the FAU structure have a distorted cubane structure similar to the FeMo-cofactor in nitrogenase, and both clusters exhibit identical catalytic activity per sulfide cluster. Additionally, these FAU-encaged clusters show superior stability compared to layered MoS2 structures under the same reaction conditions.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Arianna Actis, Michele Melchionna, Giacomo Filippini, Paolo Fornasiero, Maurizio Prato, Enrico Salvadori, Mario Chiesa
Summary: This study assesses the influence of morphology and light-excitation on the number and chemical nature of radical defects in carbon nitride (CN) and derives the spatial distribution of native radicals in CN using magnetic dipole-dipole coupling.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Biochemistry & Molecular Biology
Anne Durand, Melanie Fouesnard, Marie-Line Bourbon, Anne-Soisig Steunou, Elisabeth Lojou, Pierre Dorlet, Soufian Ouchane
Summary: The importance of copper resistance pathways in pathogenic bacteria, especially under microaerobiosis, is crucial for their survival. The CopI protein plays a significant role in copper resistance in various human bacterial pathogens and environmental bacteria, with specific amino acid residues essential for its function.
Article
Chemistry, Multidisciplinary
Yunfan Qiu, Asif Equbal, Chenjian Lin, Yuheng Huang, Paige J. Brown, Ryan M. Young, Matthew D. Krzyaniak, Michael R. Wasielewski
Summary: Photoexcited organic chromophores combined with stable radicals can be used as candidates for quantum information applications. In this study, the synthesis and characterization of 1,6,7,12-Tetra-(4-tert-butylphenoxy)-perylene-3,4 : 9,10-bis(dicarboximide) (tpPDI) linked to a partially deuterated alpha,gamma-bisdiphenylene-beta-phenylallyl radical (BDPA-d(16)) were performed using time-resolved optical and electron paramagnetic resonance (EPR) spectroscopies. The results showed efficient generation of a quartet state (Q) followed by a spin-polarized doublet ground state (D-0) upon photoexcitation of tpPDI-BDPA-d(16).
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Multidisciplinary Sciences
Qi Chen, Zhongyue Zhang, Kunio Awaga
Summary: Electrochemical energy storage using redox-active metal-organic frameworks (MOFs) has been extensively studied in the past 5 years. Despite their excellent performance in terms of capacitance and stability, the electrochemical mechanisms of MOFs are still poorly understood. Traditional spectroscopic techniques provide limited and qualitative information, leading to disputed proposed mechanisms. This article presents standardized methods to quantitatively clarify the electronic and spin state evolution within a single electrochemical step of redox-active MOFs, which can provide clear insights into energy storage mechanisms for MOFs and other materials with correlated electronic structures.
JOVE-JOURNAL OF VISUALIZED EXPERIMENTS
(2023)
Article
Chemistry, Multidisciplinary
Arianna Actis, Michele Melchionna, Giacomo Filippini, Paolo Fornasiero, Maurizio Prato, Mario Chiesa, Enrico Salvadori
Summary: Time-resolved EPR technique was used to study the formation of well-defined spin triplet excitons in carbon nitride. The mobility of the triplet excitons was revealed through the analysis of temperature-dependent TR-EPR signal. It was found that the energy of the spin triplet is approximately 0.2 eV higher than the conduction band edge, suggesting the inversion of singlet-triplet in carbon nitride materials. This study provides important insights into the response of carbon nitride to light and the nature of photoexcited states.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Biochemistry & Molecular Biology
Koji Oohora, Hirotaka Tomoda, Takashi Hayashi
Summary: The incorporation of a cobalt complex of corrole (CoCor) into an apo-form of myoglobin to provide a reconstituted protein (rMb(CoCor)) was characterized by UV-vis, EPR, and mass spectroscopic measurements. Reaction of rMb(CoCor) with hydrogen peroxide leads to irreversible oxidation of the CoCor cofactor, while the same reaction in the presence of a phenol derivative yields the cation radical form of CoCor. Detailed kinetic investigations suggest the formation of a transient hydroperoxo complex of rMb(CoCor) which promotes the oxidation of phenol derivatives.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2022)
Article
Chemistry, Inorganic & Nuclear
Rajeh Alotaibi, Amy Booth, Edmund Little, Adam Brookfield, Amritroop Achari, Selena J. Lockyer, Grigore A. Timco, George F. S. Whitehead, Inigo J. Vitorica-Yrezabal, Nicholas F. Chilton, Rahul R. Nair, David Collison, Richard E. P. Winpenny
Summary: We synthesized and characterized a series of heterometallic rings using alkylammonium or imidazolium cations as templates. The structure of these rings can be controlled by the template and the coordination geometry preference of each metal, resulting in rings with eight, nine, ten, twelve, and fourteen metals. The compounds were analyzed using various techniques, including X-ray diffraction, elemental analysis, magnetometry, and EPR measurements. The magnetic measurements showed antiferromagnetic exchange coupling between the metal centers, while the EPR spectroscopy revealed different ground and excited states for different ring structures. These findings provide insights into the transferability of magnetic parameters among related compounds.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Physical
M. Buryi, Z. Remes, V. Babin, M. Novotny, V. Vanecek, K. Aubrechtova Dragounova, J. Micova, L. Landova, R. Kucerkova, J. More-Chevalier, S. Chertopalov, P. Fitl, T. Kmjec
Summary: ZnO:Mo powders of nano- and microrods were fabricated by hydrothermal growth, while ZnO:Mo thin films were synthesized for comparison. Characterization using various techniques revealed luminescence modifications in the samples with different Mo content under annealing at elevated temperatures. The EPR spectra showed unique signals before and after treatments, indicating the presence of specific defects and luminescent properties.
APPLIED SURFACE SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Dzung Nguyen, Dinar Abdullin, Caspar A. Heubach, Toni Pfaffeneder, Andreas Nguyen, Andreas Heine, Klaus Reuter, Francois Diederich, Olav Schiemann, Gerhard Klebe
Summary: Mechanistic insights into protein-ligand interactions can provide chemical tools for modulating protein function. The type of ligand can affect the equilibrium between functional and twisted dimers in the homodimeric enzyme TGT. The experiments suggest a dissociation-association mechanism for the formation of the twisted dimer upon ligand binding.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Fabian Hecker, Lisa Fries, Markus Hiller, Mario Chiesa, Marina Bennati
Summary: The hydration structure of nitroxide radicals in aqueous solutions is studied using advanced O-17 hyperfine (hf) spectroscopy, quantum chemical calculations, and MD simulations. Two different nitroxide radicals with piperidine and pyrrolidine-based groups are compared, revealing distinct differences in the preferred direction of H-bond formation. The O-17 hf spectra provide the best representation of these scenarios, showing that in-plane coordination leads to little spin density transfer and small hf couplings, while perpendicular coordination generates larger hf couplings. The quantitative analysis based on MD simulations and DFT predicted hf parameters confirms a distribution of solvating water molecules, where directionality is influenced by steric effects.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Shiny Maity, Brad D. D. Price, C. Blake Wilson, Arnab Mukherjee, Matthieu Starck, David Parker, Maxwell Z. Z. Wilson, Janet E. E. Lovett, Songi Han, Mark S. S. Sherwin
Summary: We propose a time-resolved Gd-Gd electron paramagnetic resonance (TiGGER) technique at 240 GHz to monitor inter-residue distances in proteins' mechanical cycles in solution state. TiGGER utilizes Gd-sTPATCN spin labels with favorable properties, including spin-7/2 EPR-active center, short linker, narrow intrinsic linewidth, and minimal anisotropy at high fields. By applying TiGGER, we observed that the C-terminus and N-terminus of AsLOV2 separate within 1 s upon light activation and relax back to equilibrium with a time constant of approximately 60 s. TiGGER also revealed that the light-induced long-range mechanical motion is decelerated in the Q513A variant of AsLOV2, which is correlated with the slowed relaxation of the optically excited chromophore as reported in recent literature. TiGGER has the potential to complement existing methods for studying triggered functional dynamics in proteins.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Irina Ritsch, Elisabeth Lehmann, Leonidas Emmanouilidis, Maxim Yulikov, Frederic Allain, Gunnar Jeschke
Summary: The interaction between hnRNP A1 and specific RNA induces liquid-droplet formation, which depends on RNA concentration and sequence. Additionally, point mutations in RNA affect local protein dynamics.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Review
Chemistry, Physical
M. Anpo, G. Costentin, E. Giamello, H. Lauron-Pernot, Z. Sojka
Summary: This review provides an overview of surface oxygen species on oxide materials, including their nature, characterization, formation pathways, and involvement in catalytic and photocatalytic reactions. Special focus is given to the application of advanced techniques such as EPR and PL for detailed characterization of different oxygen species on oxide surfaces.
JOURNAL OF CATALYSIS
(2021)
Article
Biochemistry & Molecular Biology
Kamal Zeamari, Guillaume Gerbaud, Sandrine Grosse, Vincent Fourmond, Florence Chaspoul, Frederic Biaso, Pascal Arnoux, Monique Sabaty, David Pignol, Bruno Guigliarelli, Benedicte Burlat
BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS
(2019)
Article
Chemistry, Multidisciplinary
Christine Hajjar, Roberto Fanelli, Clementine Laffont, Catherine Brutesco, Gregorio Cullia, Mathilde Tribout, Didier Nurizzo, Elise Borezee-Durant, Rome Voulhoux, David Pignol, Jerome Lavergne, Florine Cavelier, Pascal Arnoux
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2019)
Article
Biochemistry & Molecular Biology
Maryam Seif Eddine, Frederic Biaso, Julia Rendon, Eric Pilet, Bruno Guigliarelli, Axel Magalon, Stephane Grimaldi
BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS
(2020)
Article
Biochemistry & Molecular Biology
Lionel Tarrago, Sandrine Grosse, David Lemaire, Laetitia Faure, Mathilde Tribout, Marina I. Siponen, Mila Kojadinovic-Sirinelli, David Pignol, Pascal Arnoux, Monique Sabaty
Article
Microbiology
Vincent Saillant, Damien Lipuma, Emeline Ostyn, Laetitia Joubert, Alain Boussac, Hugo Guerin, Geraldine Brandelet, Pascal Arnoux, Delphine Lechardeur
Summary: Enterococcus faecalis is a commensal Gram-positive pathogen found in the intestines of mammals and a leading cause of severe infections in hospitalized patients. The transcriptional regulator FhtR manages heme homeostasis in E. faecalis by controlling an efflux pump, thus regulating heme detoxification. The FhtR-HrtBAEf system is relevant in a mouse intestinal model, sensing heme fluctuations within the gastrointestinal tract.
Article
Multidisciplinary Sciences
D. Sorigue, K. Hadjidemetriou, S. Blangy, G. Gotthard, A. Bonvalet, N. Coquelle, P. Samire, A. Aleksandrov, L. Antonucci, A. Benachir, S. Boutet, M. Byrdin, M. Cammarata, S. Carbajo, S. Cuine, R. B. Doak, L. Foucar, A. Gorel, M. Grunbein, E. Hartmann, R. Hienerwadel, M. Hilpert, M. Kloos, T. J. Lane, B. Legeret, P. Legrand, Y. Li-Beisson, S. L. Y. Moulin, D. Nurizzo, G. Peltier, G. Schiro, R. L. Shoeman, M. Sliwa, X. Solinas, B. Zhuang, T. R. M. Barends, J-P Colletier, M. Joffre, A. Royant, C. Berthomieu, M. Weik, T. Domratcheva, K. Brettel, M. H. Vos, I Schlichting, P. Arnoux, P. Mueller, F. Beisson
Summary: The study found that Fatty Acid Photodecarboxylase (FAP) exhibits efficient decarboxylation activity, primarily achieved through the reduction of the flavin chromophore and direct removal of carbon dioxide by the substrate carboxyl group. Essential residues R451 and C432 are crucial for substrate stabilization and charge transfer.
Article
Biochemistry & Molecular Biology
Rodrigo Arias-Cartin, Alexandre Uzel, Farida Seduk, Guillaume Gerbaud, Fabien Pierrel, Marianne Broc, Regine Lebrun, Bruno Guigliarelli, Axel Magalon, Stephane Grimaldi, Anne Walburger
Summary: This study expands our knowledge of the FDH family by identifying a noncanonical FDH that differs in terms of architecture, amino acid conservation around the molybdenum cofactor, and reactivity.
JOURNAL OF BIOLOGICAL CHEMISTRY
(2022)
Article
Multidisciplinary Sciences
Cameron D. Fyfe, Noelia Bernardo-Garcia, Laura Fradale, Stephane Grimaldi, Alain Guillot, Clemence Brewee, Leonard M. G. Chavas, Pierre Legrand, Alhosna Benjdia, Olivier Berteau
Summary: Methyl-coenzyme M reductase plays a central role in regulating global methane levels. The study of Methanosarcina acetivorans' Mmp10 provides insights into its unique enzyme structure and catalytic control mechanism, as well as the structural changes prior to catalysis. This research is important for understanding the catalytic mechanism of the emerging superfamily of B-12-dependent radical SAM enzymes.
Article
Chemistry, Physical
Sinan Al-Attar, Julia Rendon, Marlon Sidore, Jean-Pierre Duneau, Farida Seduk, Frederic Biaso, Stephane Grimaldi, Bruno Guigliarelli, Axel Magalon
Summary: This study reports the mechanistic importance of a set of conserved residues lining the substrate entry tunnel in Escherichia coli nitrate reductase A (Nar), a paradigmatic enzyme of the Mo/W-bisPGD superfamily, and reveals their pivotal role in substrate affinity and proton transfer to the Mo active site. The research suggests that motion of Glu-581 side chain and surrounding polar residues control hydration inside the protein core, proton transfer, and substrate selectivity towards the active site, providing an additional determinant for tuning reactivity and selectivity in Nar. It is proposed that a gating mechanism is at play in several other members of the superfamily.
Meeting Abstract
Biochemistry & Molecular Biology
Pierre Dorlet, Guillaume Gerbaud, Emilien Etienne, Stephane Grimaldi, Bruno Guigliarelli, Valerie Belle
BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS
(2022)
Article
Chemistry, Multidisciplinary
Yeseul Park, Zohar Eyal, Peter Pekker, Daniel M. Chevrier, Christopher T. Lefevre, Pascal Arnoux, Jean Armengaud, Caroline L. Monteil, Assaf Gal, Mihaly Posfai, Damien Faivre
Summary: This study reports the periplasmic biomineralization of copper sulfide nanoparticles produced by the magnetotactic bacterium Desulfamplus magnetovallimortis strain BW-1. It reveals previously unknown possibilities for intracellular biomineralization and holds promise for biological metal recovery.
Article
Chemistry, Multidisciplinary
Ahmed Djeghader, Melanie Rossotti, Saleh Abdulkarim, Frederic Biaso, Guillaume Gerbaud, Wolfgang Nitschke, Barbara Schoepp-Cothenet, Tewfik Soulimane, Stephane Grimaldi
CHEMICAL COMMUNICATIONS
(2020)
Review
Biochemistry & Molecular Biology
Clementine Laffont, Pascal Arnoux