Why do zeolites induce an unprecedented electronic state on exchanged metal ions?

2017 ◽  
Vol 19 (36) ◽  
pp. 25105-25114 ◽  
Author(s):  
Akira Oda ◽  
Takahiro Ohkubo ◽  
Takashi Yumura ◽  
Hisayoshi Kobayashi ◽  
Yasushige Kuroda
Keyword(s):  
Metal Ions ◽  
Electronic State ◽  
Base Metal ◽  
Metal Ion ◽  
High Efficiency ◽  
Lewis Base ◽  
Mfi Zeolite ◽  
Adsorption Processes ◽  
Exact Position

Understanding the exact position and the detailed role of the Al array in zeolites is essential for elucidating the origin of unique properties and for designing zeolite materials with high efficiency in catalytic and adsorption processes. In this work, we advanced pivotal roles of Lewis base–metal ion bifunctionality caused by Al atoms arrayed circumferentially in the MFI-zeolite pores.

scholarly journals The Role of Metals in the Reaction Catalyzed by Metal-Ion-Independent Bacillary RNase

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Yulia Sokurenko ◽  
Vera Ulyanova ◽  
Pavel Zelenikhin ◽  
Alexey Kolpakov ◽  
Dmitriy Blokhin ◽  
...  
Keyword(s):  
Metal Ions ◽  
Rna Structure ◽  
Metal Ion ◽  
Extracellular Enzymes ◽  
Bacillus Pumilus ◽  
Transition Metal Ions ◽  
The Body ◽  
Intestinal Microbiome ◽  
Phosphodiester Bond

Extracellular enzymes of intestinal microbiota are the key agents that affect functional activity of the body as they directly interact with epithelial and immune cells. Several species of theBacillusgenus, likeBacillus pumilus, a common producer of extracellular RNase binase, can populate the intestinal microbiome as a colonizing organism. Without involving metal ions as cofactors, binase depolymerizes RNA by cleaving the 3′,5′-phosphodiester bond and generates 2′,3′-cyclic guanosine phosphates in the first stage of a catalytic reaction. Maintained in the reaction mixture for more than one hour, such messengers can affect the human intestinal microflora and the human body. In the present study, we found that the rate of 2′,3′-cGMP was growing in the presence of transition metals that stabilized the RNA structure. At the same time, transition metal ions only marginally reduced the amount of 2′,3′-cGMP, blocking binase recognition sites of guanine at N7 of nucleophilic purine bases.

scholarly journals Elucidating the role of metal ions in carbonic anhydrase catalysis

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jin Kyun Kim ◽  
Cheol Lee ◽  
Seon Woo Lim ◽  
Aniruddha Adhikari ◽  
Jacob T. Andring ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Metal Ions ◽  
Metal Ion ◽  
Catalytic Mechanism ◽  
Chemical Properties ◽  
Water Network ◽  
Native Metal ◽  
Trigonal Bipyramidal ◽  
Electrostatic Effect

Abstract Why metalloenzymes often show dramatic changes in their catalytic activity when subjected to chemically similar but non-native metal substitutions is a long-standing puzzle. Here, we report on the catalytic roles of metal ions in a model metalloenzyme system, human carbonic anhydrase II (CA II). Through a comparative study on the intermediate states of the zinc-bound native CA II and non-native metal-substituted CA IIs, we demonstrate that the characteristic metal ion coordination geometries (tetrahedral for Zn2+, tetrahedral to octahedral conversion for Co2+, octahedral for Ni2+, and trigonal bipyramidal for Cu2+) directly modulate the catalytic efficacy. In addition, we reveal that the metal ions have a long-range (~10 Å) electrostatic effect on restructuring water network in the active site. Our study provides evidence that the metal ions in metalloenzymes have a crucial impact on the catalytic mechanism beyond their primary chemical properties.

scholarly journals On the unsuspected role of multivalent metal ions on the charge storage of a metal oxide electrode in mild aqueous electrolytes

2019 ◽  
Vol 10 (38) ◽  
pp. 8752-8763 ◽  
Author(s):  
Yee-Seul Kim ◽  
Kenneth D. Harris ◽  
Benoît Limoges ◽  
Véronique Balland
Keyword(s):  
Metal Oxide ◽  
Metal Ions ◽  
Metal Ion ◽  
Charge Storage ◽  
Aqueous Electrolytes ◽  
Electron Charge ◽  
Oxide Electrode ◽  
Metal Ion Complexes ◽  
Multivalent Metal

The hidden role of hexaaquo metal ion complexes in the proton-coupled electron charge storage at a metal oxide electrode.

Towards the role of metal ions in the structural variability of proteins: CdII speciation of a metal ion binding loop motif

Metallomics ◽  
2011 ◽  
Vol 3 (12) ◽  
pp. 1331 ◽  
Author(s):  
Attila Jancsó ◽  
Dániel Szunyogh ◽  
Flemming H. Larsen ◽  
Peter W. Thulstrup ◽  
Niels Johan Christensen ◽  
...  
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Ion Binding ◽  
Metal Ion Binding ◽  
Structural Variability ◽  
Binding Loop

Selective Catalytic Reduction of NOx: Mechanistic Perspectives on the Role of Base Metal and Noble Metal Ion Substitution

2008 ◽  
Vol 47 (23) ◽  
pp. 9240-9247 ◽  
Author(s):  
Sounak Roy ◽  
A. Marimuthu ◽  
Parag A. Deshpande ◽  
M. S. Hegde ◽  
Giridhar Madras
Keyword(s):  
Selective Catalytic Reduction ◽  
Base Metal ◽  
Noble Metal ◽  
Metal Ion ◽  
Catalytic Reduction ◽  
Ion Substitution ◽  
Reduction Of Nox

The role of metal ions in the virulence and viability of bacterial pathogens

2019 ◽  
Vol 47 (1) ◽  
pp. 77-87 ◽  
Author(s):  
Stephanie L. Begg
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Molecular Mechanisms ◽  
Bacterial Pathogens ◽  
Ion Homeostasis ◽  
Transition Metal Ions ◽  
Metal Ion Homeostasis ◽  
And Function ◽  
Iron Manganese

AbstractMetal ions fulfil a plethora of essential roles within bacterial pathogens. In addition to acting as necessary cofactors for cellular proteins, making them indispensable for both protein structure and function, they also fulfil roles in signalling and regulation of virulence. Consequently, the maintenance of cellular metal ion homeostasis is crucial for bacterial viability and pathogenicity. It is therefore unsurprising that components of the immune response target and exploit both the essentiality of metal ions and their potential toxicity toward invading bacteria. This review provides a brief overview of the transition metal ions iron, manganese, copper and zinc during infection. These essential metal ions are discussed in the context of host modulation of bioavailability, bacterial acquisition and efflux, metal-regulated virulence factor expression and the molecular mechanisms that contribute to loss of viability and/or virulence during host-imposed metal stress.

scholarly journals Metal ion removal using waste byssus from aquaculture

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Devis Montroni ◽  
Giorgia Giusti ◽  
Andrea Simoni ◽  
Genny Cau ◽  
Claudio Ciavatta ◽  
...  
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
High Efficiency ◽  
Water Remediation ◽  
Isotherm Models ◽  
Metal Ion Removal ◽  
Chemical Systems ◽  
Ion Removal ◽  
Adsorption Isotherm Models ◽  
Ideal Solutions

AbstractByssus is a thread-like seafood waste that has a natural high efficiency in anchoring many metal ions thanks to its richness of diverse functional groups. It also has structural stability in extreme chemical, physical and mechanical conditions. The combination of these properties, absent in other waste materials, has novelty suggested its use as matrix for water remediation. Thus, pristine byssus, upon de-metalation, was studied to remove metal ions from ideal solutions at pH 4 and 7, as model chemical systems of industrial and environmental polluted waters, respectively. The byssus matrix’s uptake of metal ions was determined by ICP-OES and its surface microstructure investigated by SEM. The results showed that the byssus matrix excellently uptakes metal ions slightly reorganizing its surface micro-structure. As example of its efficiency: 50 mg of byssus absorbed 21.7 mg·g−1 of Cd2+ from a 10 mM solution at pH 7. The adsorption isotherm models of Freundlich and Langmuir were mainly used to describe the system at pH 7 and pH 4, respectively. In conclusion, we showed that the byssus, a waste material that is an environmental issue, has the potential to purify polluted industrial and environmental waters from metal ions.

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