scholarly journals Metal-Specificity Divergence between Metallothioneins of Nerita peloronta (Neritimorpha, Gastropoda) Sets the Starting Point for a Novel Chemical MT Classification Proposal

2021 ◽  
Vol 22 (23) ◽  
pp. 13114
Author(s):  
Mario García-Risco ◽  
Sara Calatayud ◽  
Veronika Pedrini-Martha ◽  
Ricard Albalat ◽  
Reinhard Dallinger ◽  
...  
Keyword(s):  
Metal Binding ◽  
High Selectivity ◽  
Biological Function ◽  
Divalent Metal ◽  
The Other ◽  
Divalent Metal Ions ◽  
Specific Group ◽  
Metal Specificity ◽  
Starting Point ◽  
New Perspective

Metallothioneins’ (MTs) biological function has been a matter of debate since their discovery. The importance to categorize these cysteine-rich proteins with high coordinating capacity into a specific group led to numerous classification proposals. We proposed a classification based on their metal-binding abilities, gradually sorting them from those with high selectivity towards Zn/Cd to those that are Cu-specific. However, the study of the NpeMT1 and NpeMT2isoforms of Nerita peloronta, has put a new perspective on this classification. N. peloronta has been chosen as a representative mollusk to elucidate the metal-binding abilities of Neritimorpha MTs, an order without any MTs characterized recently. Both isoforms have been recombinantly synthesized in cultures supplemented with ZnII, CdII, or CuII, and the purified metal–MT complexes have been thoroughly characterized by spectroscopic and spectrometric methods, leading to results that confirmed that Neritimorpha share Cd-selective MTs with Caenogastropoda and Heterobranchia, solving a so far unresolved question. NpeMTs show high coordinating preferences towards divalent metal ions, although one of them (NpeMT1) shares features with the so-called genuine Zn-thioneins, while the other (NpeMT2) exhibits a higher preference for Cd. The dissimilarities between the two isoforms let a window open to a new proposal of chemical MT classification.

scholarly journals Regulation of divalent metal ions to the aggregation and membrane damage of human islet amyloid polypeptide oligomers

RSC Advances ◽  
2021 ◽  
Vol 11 (21) ◽  
pp. 12815-12825
Author(s):  
Yajie Wang ◽  
Feihong Meng ◽  
Tong Lu ◽  
Chunyun Wang ◽  
Fei Li
Keyword(s):  
Metal Ions ◽  
Metal Binding ◽  
Membrane Damage ◽  
Islet Amyloid Polypeptide ◽  
Divalent Metal ◽  
Human Islet ◽  
Divalent Metal Ions ◽  
Islet Amyloid ◽  
Induced Membrane ◽  
Human Islet Amyloid Polypeptide

Their is a counteraction between a decrease in the disruptive ability of metal-associated oligomer species and an increase in the quantity of oligomers promoted by the metal binding in the activity of hIAPP induced membrane damage.

scholarly journals HK97 gp74 Possesses an α-Helical Insertion in the ββα Fold That Affects Its Metal Binding, cos Site Digestion, and In Vivo Activities

2020 ◽  
Vol 202 (8) ◽  
Author(s):  
Sasha A. Weiditch ◽  
Sarah C. Bickers ◽  
Diane Bona ◽  
Karen L. Maxwell ◽  
Voula Kanelis
Keyword(s):  
Metal Binding ◽  
Metal Ion ◽  
Divalent Metal ◽  
Metal Ion Binding ◽  
Divalent Metal Ions ◽  
Nmr Studies ◽  
Phage Dna ◽  
Divalent Metal Ion ◽  
Phage Morphogenesis

ABSTRACT The last gene in the genome of the bacteriophage HK97 encodes gp74, an HNH endonuclease. HNH motifs contain two conserved His residues and an invariant Asn residue, and they adopt a ββα structure. gp74 is essential for phage head morphogenesis, likely because gp74 enhances the specific endonuclease activity of the HK97 terminase complex. Notably, the ability of gp74 to enhance the terminase-mediated cleavage of the phage cos site requires an intact HNH motif in gp74. Mutation of H82, the conserved metal-binding His residue in the HNH motif, to Ala abrogates gp74-mediated stimulation of terminase activity. Here, we present nuclear magnetic resonance (NMR) studies demonstrating that gp74 contains an α-helical insertion in the Ω-loop, which connects the two β-strands of the ββα fold, and a disordered C-terminal tail. NMR data indicate that the Ω-loop insert makes contacts to the ββα fold and influences the ability of gp74 to bind divalent metal ions. Further, the Ω-loop insert and C-terminal tail contribute to gp74-mediated DNA digestion and to gp74 activity in phage morphogenesis. The data presented here enrich our molecular-level understanding of how HNH endonucleases enhance terminase-mediated digestion of the cos site and contribute to the phage replication cycle. IMPORTANCE This study demonstrates that residues outside the canonical ββα fold, namely, the Ω-loop α-helical insert and a disordered C-terminal tail, regulate the activity of the HNH endonuclease gp74. The increased divalent metal ion binding when the Ω-loop insert is removed compared to reduced cos site digestion and phage formation indicates that the Ω-loop insert plays multiple regulatory roles. The data presented here provide insights into the molecular basis of the involvement of HNH proteins in phage DNA packing.

Inhibition of glycogen synthase (casein) kinase-1 by divalent metal ions

1988 ◽  
Vol 66 (3) ◽  
pp. 238-243 ◽  
Author(s):  
Toolsee J. Singh
Keyword(s):  
Metal Ions ◽  
Kinase Activity ◽  
Glycogen Synthase ◽  
Divalent Metal ◽  
Casein Kinase ◽  
The Other ◽  
Divalent Metal Ions ◽  
Casein Kinase 1 ◽  
Competitive Inhibitors ◽  
Noncompetitive Inhibitors

The specificity of glycogen synthase (casein) kinase-1 (CK-1) for different divalent metal ions was explored in this study. Of nine metal ions (Mg2+, Mn2+, Zn2+, Cu2+, Ca2+, Ba2+, Ni2+, Co2+, Fe2+) tested, only Mg2+ supported significant kinase activity. Several of the other metals, however, inhibited the Mg2+-stimulated kinase activity. Half-maximal inhibitions by Mn2+, Zn2+, Co2+, Fe2+, and Ni2+ were observed at 55, 65, 110, 125, and 284 μM, respectively. Kinetic analyses indicate that the metal ions are acting as competitive inhibitors of CK-1 with respect to the protein substrate (casein) and as noncompetitive inhibitors with respect to the nucleotide substrate (ATP). The inhibition of CK-1 by the different metal ions can be reversed by EGTA.

scholarly journals Synthesis, Characterization and Cytotoxicity of Ni (II), Pd (II), Pt (II) Complexes with 6-Methoxy-2, 3, 4, 5-tetrahydropyridine (MTP)

2020 ◽  
Vol 36 (05) ◽  
pp. 903-907
Author(s):  
Hikmat Ali Mohamad ◽  
Widad Taha Al-Kattan ◽  
Zena Mashal Al-Daly ◽  
Ali Nafia Najim
Keyword(s):  
Magnetic Susceptibility ◽  
Divalent Metal ◽  
Molar Conductivity ◽  
The Other ◽  
Divalent Metal Ions ◽  
Square Planar ◽  
Ft Ir ◽  
Colored Complexes ◽  
Cytotoxicity Effects ◽  
Mcf 7

Reaction of 2 moles of (MTP) with one mole of MCl2 gave colored complexes with general formula; [M(MTP)2Cl2]. [M = Ni+2, Pd+2, and Pt+2]. All synthesized complexes are well-characterized using, FT-IR, 1HNMR, 13C NMR, UV-Vis. Spectra furthermore of magnetic susceptibility, C,H,N analysis, and molar conductivity. The results illustrated that divalent metal ions were coordinated with the ligands through nitrogen atoms in square planar spatial arrangements. The complexes were screened for their cytotoxicity effects versus MCF-7 cell line and showed that [Pt(MTP)2Cl2] complex has good cytotoxicity in comparison with the other complexes.

scholarly journals MOTOR END PLATE REACTIVITY TO DIVALENT METAL IONS HISTOCHEMICAL STUDIES

1967 ◽  
Vol 15 (5) ◽  
pp. 276-284 ◽  
Author(s):  
TOSHIO NAKAMURA ◽  
TATSUJI NAMBA ◽  
DAVID GROB
Keyword(s):  
Metal Ions ◽  
Metal Binding ◽  
Calcium Release ◽  
Cholinesterase Activity ◽  
Divalent Metal ◽  
Divalent Metal Ions ◽  
Alizarin Red ◽  
End Plate ◽  
Motor End Plate

Motor end plates in the tibialis anterior muscle of the rat were demonstrated by metal sulfide deposits following injection of aqueous solutions of lead, stannous, cadmium, zinc or cupric ions into the muscle in vivo or in vitro. The appearance of the end plates was similar to the structure demonstrated by cholinesterase staining, with visualization of the subneural apparatus. Neither metal binding nor cholinesterase activity was affected 4 weeks after dissection of the sciatic nerve, indicating that the metal binding site is postsynaptic. Freezing or formalin fixation of muscle prevented binding of all metal ions to the end plate without greatly affecting cholinesterase activity, indicating that these two activities of the end plate are distinct. Prior administration of acetylcholine, d-tubocurarine, neostigmine or diisopropyl fluorophosphate inhibited binding to the end plate of cadmium and zinc ions but did not alter binding of lead and stannous ions. By formation of a lake with alizarin red S previously injected in vivo intramuscularly, the release of calcium ions at the motor end plate following stimulation of the muscle through the nerve or administration of neostigmine was demonstrated. These results suggest a close relationship of the site of binding of divalent metal ions in the motor end plate to the site of calcium release, and a close but not identical relationship to the site of cholinesterase activity and the acetylcholine receptor.

Influence of monovalent metal ions on metal binding and catalytic activity of the 10–23 DNAzyme

2020 ◽  
Vol 402 (1) ◽  
pp. 99-111
Author(s):  
Hannah Rosenbach ◽  
Jan Borggräfe ◽  
Julian Victor ◽  
Christine Wuebben ◽  
Olav Schiemann ◽  
...  
Keyword(s):  
Metal Ions ◽  
Metal Binding ◽  
Divalent Cations ◽  
Reaction Rates ◽  
Divalent Metal ◽  
Divalent Metal Ions ◽  
Monovalent Metal ◽  
Biophysical Techniques ◽  
Target Rna

AbstractDeoxyribozymes (DNAzymes) are single-stranded DNA molecules that catalyze a broad range of chemical reactions. The 10–23 DNAzyme catalyzes the cleavage of RNA strands and can be designed to cleave essentially any target RNA, which makes it particularly interesting for therapeutic and biosensing applications. The activity of this DNAzyme in vitro is considerably higher than in cells, which was suggested to be a result of the low intracellular concentration of bioavailable divalent cations. While the interaction of the 10–23 DNAzyme with divalent metal ions was studied extensively, the influence of monovalent metal ions on its activity remains poorly understood. Here, we characterize the influence of monovalent and divalent cations on the 10–23 DNAzyme utilizing functional and biophysical techniques. Our results show that Na+ and K+ affect the binding of divalent metal ions to the DNAzyme:RNA complex and considerably modulate the reaction rates of RNA cleavage. We observe an opposite effect of high levels of Na+ and K+ concentrations on Mg2+- and Mn2+-induced reactions, revealing a different interplay of these metals in catalysis. Based on these findings, we propose a model for the interaction of metal ions with the DNAzyme:RNA complex.

Interaction of divalent metal ions with the NADP+-malic enzyme from maize leaves

1991 ◽  
Vol 81 (4) ◽  
pp. 462-466 ◽  
Author(s):  
Maria Fabiana Drincovich ◽  
Alberto A. Iglesias ◽  
Carlos S. Andreo
Keyword(s):  
Metal Ions ◽  
Malic Enzyme ◽  
Divalent Metal ◽  
Divalent Metal Ions ◽  
Maize Leaves

Lorenzo at ‘The Theatre’ Meeting actors and audience

2018 ◽  
pp. 13-38
Author(s):  
N. Ceramella
Keyword(s):  
Social Structure ◽  
Social Situation ◽  
The Other ◽  
Detailed Account ◽  
The Social ◽  
New Perspective ◽  
The One

The article considers two versions of D. H. Lawrence’s essay The Theatre: the one which appeared in the English Review in September 1913 and the other one which Lawrence published in his first travel book Twilight in Italy (1916). The latter, considerably revised and expanded, contains a number of new observations and gives a more detailed account of Lawrence’s ideas.Lawrence brings to life the atmosphere inside and outside the theatre in Gargnano, presenting vividly the social structure of this small northern Italian town. He depicts the theatre as a multi-storey stage, combining the interpretation of the plays by Shakespeare, D’Annunzio and Ibsen with psychological portraits of the actors and a presentation of the spectators and their responses to the plays as distinct social groups.Lawrence’s views on the theatre are contextualised by his insights into cinema and its growing popularity.What makes this research original is the fact that it offers a new perspective, aiming to illustrate the social situation inside and outside the theatre whichLawrenceobserved. The author uses the material that has never been published or discussed before such as the handwritten lists of box-holders in Gargnano Theatre, which was offered to Lawrence and his wife Frieda by Mr. Pietro Comboni, and the photographs of the box-panels that decorated the theatre inLawrence’s time.

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