scholarly journals Experimental and Theoretical Investigations of a Ferrous / Ascorbate Complex

2021 ◽  
Author(s):  
◽  
Margaret Lockhart Dickson
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Theoretical Calculations ◽  
Transition Metal Ions ◽  
The Body ◽  
Trace Metal Ions ◽  
Transition Series ◽  
Theoretical Investigations ◽  
Vitamin B 12

<p>The importance of trace metal ions in biological processes has been known for some time, but the role of chelating molecules in the human body is a comparatively new and interesting field of research Schubert, j., 1966, Scientific American, 214, no. 5, 40. Among the important complexes occuring in the body are haemoglobin, containing iron, and vitamin B-12, containing cobalt, both essential to human health. Other well-known naturally occuring complexes include cytochrome oxidase, containing both iron and copper, and chlorophyll, containing magnesium. The transition metal ions of the First Transition Series are well-known for their ability to form complexes with suitable ligands, and in particular with chelate ligands which can seize the metal ion like a claw (chele means claw in Greek). Many of these complexes have been characterized experimentally, and their properties interpreted by theoretical calculations. However, the complexes arising from biological systems are much more difficult to study, partly because of their greater size and special properties.</p>

scholarly journals Experimental and Theoretical Investigations of a Ferrous / Ascorbate Complex

2021 ◽  
Author(s):  
◽  
Margaret Lockhart Dickson
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Theoretical Calculations ◽  
Transition Metal Ions ◽  
The Body ◽  
Trace Metal Ions ◽  
Transition Series ◽  
Theoretical Investigations ◽  
Vitamin B 12

<p>The importance of trace metal ions in biological processes has been known for some time, but the role of chelating molecules in the human body is a comparatively new and interesting field of research Schubert, j., 1966, Scientific American, 214, no. 5, 40. Among the important complexes occuring in the body are haemoglobin, containing iron, and vitamin B-12, containing cobalt, both essential to human health. Other well-known naturally occuring complexes include cytochrome oxidase, containing both iron and copper, and chlorophyll, containing magnesium. The transition metal ions of the First Transition Series are well-known for their ability to form complexes with suitable ligands, and in particular with chelate ligands which can seize the metal ion like a claw (chele means claw in Greek). Many of these complexes have been characterized experimentally, and their properties interpreted by theoretical calculations. However, the complexes arising from biological systems are much more difficult to study, partly because of their greater size and special properties.</p>

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 Hypochlorite and superoxide radicals can act synergistically to induce fragmentation of hyaluronan and chondroitin sulphates

2004 ◽  
Vol 381 (1) ◽  
pp. 175-184 ◽  
Author(s):  
Martin D. REES ◽  
Clare L. HAWKINS ◽  
Michael J. DAVIES
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Transition Metal Ions ◽  
Chloride Ions ◽  
Superoxide Radicals ◽  
Thermal Source ◽  
Site Specific ◽  
Trace Metal Ions ◽  
Electron Reduction ◽  
Polymer Fragmentation

Activated phagocytes release the haem enzyme MPO (myeloperoxidase) and also generate superoxide radicals (O2•−), and hence H2O2, via an oxidative burst. Reaction of MPO with H2O2 in the presence of chloride ions generates HOCl (the physiological mixture of hypochlorous acid and its anion present at pH 7.4). Exposure of glycosaminoglycans to a MPO–H2O2–Cl− system or reagent HOCl generates long-lived chloramides [R-NCl-C(O)-R′] derived from the glycosamine N-acetyl functions. Decomposition of these species by transition metal ions gives polymer-derived amidyl (nitrogen-centred) radicals [R-N•-C(O)-R′], polymer-derived carbon-centred radicals and site-specific strand scission. In the present study, we have shown that exposure of glycosaminoglycan chloramides to O2•− also promotes chloramide decomposition and glycosaminoglycan fragmentation. These processes are inhibited by superoxide dismutase, metal ion chelators and the metal ion-binding protein BSA, consistent with chloramide decomposition and polymer fragmentation occurring via O2•−-dependent one-electron reduction, possibly catalysed by trace metal ions. Polymer fragmentation induced by O2•− [generated by the superoxide thermal source 1, di-(4-carboxybenzyl)hyponitrite] was demonstrated to be entirely chloramide dependent as no fragmentation occurred with the native polymers or when the chloramides were quenched by prior treatment with methionine. EPR spin-trapping experiments using 5,5-dimethyl1-pyrroline-N-oxide and 2-methyl-2-nitrosopropane have provided evidence for both O2•− and polymer-derived carbon-centred radicals as intermediates. The results obtained are consistent with a mechanism involving one-electron reduction of the chloramides to yield polymer-derived amidyl radicals, which subsequently undergo intramolecular hydrogen atom abstraction reactions to give carbon-centred radicals. The latter undergo fragmentation reactions in a site-specific manner. This synergistic damage to glycosaminoglycans induced by HOCl and O2•− may be of significance at sites of inflammation where both oxidants are generated concurrently.

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 The Role of Divalent Transition Metal Ions in the Binding of Fur Dimer to DNA: Binding of Mn2+ and Co2+ to EC Fur dimer-DNA Complex

2020 ◽  
Author(s):  
Mazen Hamed
Keyword(s):  
Dna Binding ◽  
Transition Metal ◽  
Metal Ions ◽  
Conformational Changes ◽  
Metal Ion ◽  
Transition Metal Ions ◽  
Rich Region ◽  
Repressor Protein ◽  
Dna Complex

Ferric uptake regulation protein is a repressor protein which binds an AT rich region of DNA (the iron box). Fur binds as a dimer in a helix turn helix mode and it is activated by iron(II) and other transition metal ions at elevated concentrations. Each transition metal ion induces certain conformational changes to aid the Fur binding, both the N-terminal and C-terminal domains take part in binding to DNA in addition to His 88 and His 86. The process is discussed in view of experimental reports. Fe(II), Mn(II) and Co(II) activate Fur to bind DNA but Zinc plays a structural role and does not activate Fur to bind DNA.

scholarly journals The Role of Divalent Transition Metal Ions in the Binding of Fur Dimer to DNA: Binding of Mn2+ and Co2+ to EC Fur dimer-DNA Complex

2020 ◽  
Author(s):  
Mazen Hamed ◽  
Salih Jabour
Keyword(s):  
Dna Binding ◽  
Transition Metal ◽  
Metal Ions ◽  
Conformational Changes ◽  
Metal Ion ◽  
Transition Metal Ions ◽  
Rich Region ◽  
Repressor Protein ◽  
Dna Complex

Ferric uptake regulation protein is a repressor protein which binds an AT rich region of DNA (the iron box). Fur binds as a dimer in a helix turn helix mode and it is activated by iron(II) and other transition metal ions at elevated concentrations. Each transition metal ion induces certain conformational changes to aid the Fur binding, both the N-terminal and C-terminal domains take part in binding to DNA in addition to His 88 and His 86. The process is discussed in view of experimental reports. Fe(II), Mn(II) and Co(II) activate Fur to bind DNA but Zinc plays a structural role and does not activate Fur to bind DNA.

scholarly journals The Role of Divalent Transition Metal Ions in the Binding of Fur Dimer to DNA: Binding of Mn2+ and Co2+ to EC Fur dimer-DNA Complex

2020 ◽  
Author(s):  
Mazen Hamed ◽  
Salih Jabour
Keyword(s):  
Dna Binding ◽  
Transition Metal ◽  
Metal Ions ◽  
Conformational Changes ◽  
Metal Ion ◽  
Transition Metal Ions ◽  
Rich Region ◽  
Repressor Protein ◽  
Dna Complex

Ferric uptake regulation protein is a repressor protein which binds an AT rich region of DNA (the iron box). Fur binds as a dimer in a helix turn helix mode and it is activated by iron(II) and other transition metal ions at elevated concentrations. Each transition metal ion induces certain conformational changes to aid the Fur binding, both the N-terminal and C-terminal domains take part in binding to DNA in addition to His 88 and His 86. The process is discussed in view of experimental reports. Fe(II), Mn(II) and Co(II) activate Fur to bind DNA but Zinc plays a structural role and does not activate Fur to bind DNA.

scholarly journals The Role of Divalent Transition Metal Ions in the Binding of Fur Dimer to DNA: Binding of Mn2+ and Co2+ to EC Fur dimer-DNA Complex

2020 ◽  
Author(s):  
Mazen Hamed ◽  
Salih Jabour
Keyword(s):  
Dna Binding ◽  
Transition Metal ◽  
Metal Ions ◽  
Conformational Changes ◽  
Metal Ion ◽  
Transition Metal Ions ◽  
Rich Region ◽  
Repressor Protein ◽  
Dna Complex

Ferric uptake regulation protein is a repressor protein which binds an AT rich region of DNA (the iron box). Fur binds as a dimer in a helix turn helix mode and it is activated by iron(II) and other divalent transition metal ions at elevated concentrations in a process to regulate the ion uptake. Each transition metal ion induces certain conformational changes to aid the Fur binding, both the N-terminal and C-terminal domains take part in binding to DNA in addition to His 88 and His 86 residues. The process is discussed in view of experimental reports. Fe(II), Mn(II) and Co(II) activate Fur to bind DNA experimentally but Zinc plays a structural role and does not activate Fur to bind DNA.

scholarly journals The Role of the Disulfide Bridge in the Copper (II) Binding by the Cyclic His4-Peptide

2021 ◽  
Vol 22 (12) ◽  
pp. 6458
Author(s):  
Aleksandra Pieniężna ◽  
Weronika Witak ◽  
Aneta Szymańska ◽  
Justyna Brasuń
Keyword(s):  
Metal Ions ◽  
Coordination Mode ◽  
Transition Metal Ions ◽  
Disulfide Bridge ◽  
Chain Flexibility ◽  
Vis Spectroscopy ◽  
Ph Range ◽  
Cd Studies ◽  
Metal Ratios

In this paper, we present studies on the influence of the disulfide bridge on the copper (II) ions’ binding abilities by the cyclic His4-peptide. The studied ligand HKHPHRHC-S-S-C consists of nine amino acids. The cyclic structure was obtained through a disulfide bridge between two cysteinyl groups. Moreover, this peptide is characterized by the presence of four His residues in the sequence, which makes it an interesting ligand for transition metal ions. The potentiometric and spectroscopic (UV-Vis spectroscopy and circular dichroism spectroscopy (CD)) studies were carried out in various molar ligand to metal ratios: 2:1, 1:1, and 1:2, in the pH range of 2.5–11 at 25 °C. The results showed that the cyclic His4-peptide promotes dinuclear complexes in each of these systems and forms the final dinuclear species with the {NIm, 3N-amide}{NIm, 3N-amide} coordination mode. The obtained data shows that cyclization by the formation of the disulfide bond has an impact on the peptide chain flexibility and appearance of additional potential donors for metal ions and influences the copper (II) ions’ coordination.

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