Cation diffusion facilitators (CDF) are part of a highly conserved protein family that maintains ... more Cation diffusion facilitators (CDF) are part of a highly conserved protein family that maintains cellular divalent cation homeostasis in all domains of life. CDF's were shown to be involved in several human diseases, such as Type-II diabetes and neurodegenerative diseases. In this work, we employed a multidisciplinary approach to study the activation mechanism of the CDF protein family. For this we used MamM, one of the main ion transporters of magnetosomes-bacterial organelles that enable magnetotactic bacteria to orientate along geomagnetic fields. Our results reveal that the cytosolic domain of MamM forms a stable dimer that undergoes distinct conformational changes upon divalent cation binding. MamM conformational change is associated with three metal binding sites that were identified and characterized. Altogether, our results provide a novel auto-regulation mode of action model in which the cytosolic domain's conformational changes upon ligand binding allows the priming of the CDF into its transport mode.
The need for low-cost, high-safety batteries for large-scale energy storage applications has spar... more The need for low-cost, high-safety batteries for large-scale energy storage applications has sparked a surge in research of rechargeable aqueous batteries. While most research efforts are focused on the development of electrolyte formulations and electrode materials, it appears that the current collector impact on the battery performance is frequently overlooked. Even though the current collector is traditionally thought of as an inactive battery component, it is included in the battery energy density calculations, making its activation desirable. Furthermore, poor current collector selection can cause irreversible side reactions, resulting in rapid cell efficiency decay. Herein we propose a new approach to design current collectors that makes use of anodized Ti. The redox-active anodized Ti significantly improves the overall anode capacity and provides effective inhibition of hydrogen formation on the electrified interface. The use of TiO2 particles on an anodized Ti current collec...
Deriving the conformation of adsorbed proteins is important in the assessment of their functional... more Deriving the conformation of adsorbed proteins is important in the assessment of their functional activity when immobilized. This has particularly important bearings on the design of contemporary and new encapsulated enzyme-based drugs, biosensors, and other bioanalytical devices. Solid-state nuclear magnetic resonance (NMR) measurements can expand our molecular view of proteins in this state and of the molecular interactions governing protein immobilization on popular biocompatible surfaces such as silica. Here, the authors study the immobilization of ubiquitin on the mesoporous silica MCM41 by NMR and other techniques. Protein molecules are shown to bind efficiently at pH 5 through electrostatic interactions to individual MCM41 particles, causing their agglutination. The strong attraction of ubiquitin to MCM41 surface is given molecular context through evidence of proximity of basic, carbonyl and polar groups on the protein to groups on the silica surface using NMR measurements. T...
Non-collagenous proteins such as osteocalcin function as regulators of the mineralization process... more Non-collagenous proteins such as osteocalcin function as regulators of the mineralization process in bone. Osteocalcin undergoes post-translational modification adding an extra carboxylate group on three of its glutamate residues to enhance interaction with bone mineral. In this work, we examine regulation of biomimetic apatite formation by osteocalcin that was not modified after translation. We analyze the structural features in the protein and mineral-protein interfaces to elicit the unmodified protein's fold inside the mineral and to unveil the species that interact with the mineral surface. The results presented here give clues on the protein's active role in controlling the mineral phases that are formed on hydroxyapatite crystals and its ability to influence the extent of order in these crystals.
Protein immobilization on material surfaces is emerging as a powerful tool in the design of devic... more Protein immobilization on material surfaces is emerging as a powerful tool in the design of devices and active materials for biomedical and pharmaceutical applications as well as for catalysis. Preservation of the protein's biological functionality is crucial to the design process and is dependent on the ability to maintain its structural and dynamical integrity while removed from the natural surroundings. The scientific techniques to validate the structure of immobilized proteins are scarce and usually provide limited information as a result of poor resolution. In this work, we benchmarked the ability of standard solid-state NMR techniques to resolve the effects of binding to dissimilar silica materials on a model protein. In particular, the interactions between ubiquitin and the surfaces of MCM41, SBA15, and silica formed in situ were tested for their influence on the structure and dynamics of the protein. It is shown that the protein's globular fold in the free state is only slightly perturbed in the three silica materials. Local motions on a residue level that are quenched by immobilization or, conversely, that arise from the process are also detailed. NMR measurements show that these perturbations are unique to each silica material and can serve as reporters of the characteristic surface chemistry.
Cation diffusion facilitators (CDF) are part of a highly conserved protein family that maintains ... more Cation diffusion facilitators (CDF) are part of a highly conserved protein family that maintains cellular divalent cation homeostasis in all domains of life. CDF's were shown to be involved in several human diseases, such as Type-II diabetes and neurodegenerative diseases. In this work, we employed a multidisciplinary approach to study the activation mechanism of the CDF protein family. For this we used MamM, one of the main ion transporters of magnetosomes-bacterial organelles that enable magnetotactic bacteria to orientate along geomagnetic fields. Our results reveal that the cytosolic domain of MamM forms a stable dimer that undergoes distinct conformational changes upon divalent cation binding. MamM conformational change is associated with three metal binding sites that were identified and characterized. Altogether, our results provide a novel auto-regulation mode of action model in which the cytosolic domain's conformational changes upon ligand binding allows the priming of the CDF into its transport mode.
The need for low-cost, high-safety batteries for large-scale energy storage applications has spar... more The need for low-cost, high-safety batteries for large-scale energy storage applications has sparked a surge in research of rechargeable aqueous batteries. While most research efforts are focused on the development of electrolyte formulations and electrode materials, it appears that the current collector impact on the battery performance is frequently overlooked. Even though the current collector is traditionally thought of as an inactive battery component, it is included in the battery energy density calculations, making its activation desirable. Furthermore, poor current collector selection can cause irreversible side reactions, resulting in rapid cell efficiency decay. Herein we propose a new approach to design current collectors that makes use of anodized Ti. The redox-active anodized Ti significantly improves the overall anode capacity and provides effective inhibition of hydrogen formation on the electrified interface. The use of TiO2 particles on an anodized Ti current collec...
Deriving the conformation of adsorbed proteins is important in the assessment of their functional... more Deriving the conformation of adsorbed proteins is important in the assessment of their functional activity when immobilized. This has particularly important bearings on the design of contemporary and new encapsulated enzyme-based drugs, biosensors, and other bioanalytical devices. Solid-state nuclear magnetic resonance (NMR) measurements can expand our molecular view of proteins in this state and of the molecular interactions governing protein immobilization on popular biocompatible surfaces such as silica. Here, the authors study the immobilization of ubiquitin on the mesoporous silica MCM41 by NMR and other techniques. Protein molecules are shown to bind efficiently at pH 5 through electrostatic interactions to individual MCM41 particles, causing their agglutination. The strong attraction of ubiquitin to MCM41 surface is given molecular context through evidence of proximity of basic, carbonyl and polar groups on the protein to groups on the silica surface using NMR measurements. T...
Non-collagenous proteins such as osteocalcin function as regulators of the mineralization process... more Non-collagenous proteins such as osteocalcin function as regulators of the mineralization process in bone. Osteocalcin undergoes post-translational modification adding an extra carboxylate group on three of its glutamate residues to enhance interaction with bone mineral. In this work, we examine regulation of biomimetic apatite formation by osteocalcin that was not modified after translation. We analyze the structural features in the protein and mineral-protein interfaces to elicit the unmodified protein's fold inside the mineral and to unveil the species that interact with the mineral surface. The results presented here give clues on the protein's active role in controlling the mineral phases that are formed on hydroxyapatite crystals and its ability to influence the extent of order in these crystals.
Protein immobilization on material surfaces is emerging as a powerful tool in the design of devic... more Protein immobilization on material surfaces is emerging as a powerful tool in the design of devices and active materials for biomedical and pharmaceutical applications as well as for catalysis. Preservation of the protein's biological functionality is crucial to the design process and is dependent on the ability to maintain its structural and dynamical integrity while removed from the natural surroundings. The scientific techniques to validate the structure of immobilized proteins are scarce and usually provide limited information as a result of poor resolution. In this work, we benchmarked the ability of standard solid-state NMR techniques to resolve the effects of binding to dissimilar silica materials on a model protein. In particular, the interactions between ubiquitin and the surfaces of MCM41, SBA15, and silica formed in situ were tested for their influence on the structure and dynamics of the protein. It is shown that the protein's globular fold in the free state is only slightly perturbed in the three silica materials. Local motions on a residue level that are quenched by immobilization or, conversely, that arise from the process are also detailed. NMR measurements show that these perturbations are unique to each silica material and can serve as reporters of the characteristic surface chemistry.
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Papers by Merav Tsubery