scholarly journals Urea Gel Electrophoresis in Studies of Conformational Changes of Transferrin on Binding and Transport of Non-Ferric Metal Ions

Gels ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 19
Author(s):  
Aviva Levina ◽  
Boer Wang ◽  
Peter A. Lay
Keyword(s):  
Metal Ions ◽  
Conformational Changes ◽  
Gel Electrophoresis ◽  
Metal Ion ◽  
Polyacrylamide Gel Electrophoresis ◽  
Ion Binding ◽  
Metal Ion Binding ◽  
Transporter Protein ◽  
Systematic Exploration ◽  
Acidic Conditions

Transferrin (Tf) is a crucial transporter protein for Fe(III), but its biological role in binding other metal ions and their delivery into cells remain highly controversial. The first systematic exploration of the effect of non-Fe(III) metal ion binding on Tf conformation has been performed by urea-polyacrylamide gel electrophoresis (urea-PAGE), which is commonly used for nucleic acids but rarely for proteins. Closed Tf conformation, similar to that caused by Fe(III)-Tf binding, was formed for In(III), V(III) or Cr(III) binding to Tf. In all these cases, metal distribution between Tf lobes and/or the rate of metal release under acidic conditions differed from that of Fe(III)-Tf. By contrast, Ga(III) and V(IV) did not form closed Tf conformation under urea-PAGE conditions. Apart from Fe(III), only In(III) was able to increase the proportion of closed Tf conformation in whole serum. These results suggest that Tf is unlikely to act as a natural carrier of any metal ion, except Fe(III), into cells but can reduce toxicity of exogenous metal ions by binding them in serum and preventing their entry into cells.

The influence of metal-ion binding on the structure and surface composition of Sonic Hedgehog: a combined classical and hybrid QM/MM MD study

2016 ◽  
Vol 18 (32) ◽  
pp. 22254-22265 ◽  
Author(s):  
Manuel Hitzenberger ◽  
Thomas S. Hofer
Keyword(s):  
Metal Ions ◽  
Sonic Hedgehog ◽  
Binding Sites ◽  
Metal Ion ◽  
Surface Composition ◽  
Quantum Mechanical ◽  
Ion Binding ◽  
Metal Ion Binding ◽  
Structural Impact

The interaction of metal ions with Shh binding-sites and their structural impact are assessed via classical and quantum mechanical simulations.

scholarly journals Functional characterization of the dimerization domain of the ferric uptake regulator (Fur) of Pseudomonas aeruginosa

2006 ◽  
Vol 400 (3) ◽  
pp. 385-392 ◽  
Author(s):  
Erdeni Bai ◽  
Federico I. Rosell ◽  
Bao Lige ◽  
Marcia R. Mauk ◽  
Barbara Lelj-Garolla ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Metal Ions ◽  
Binding Site ◽  
Metal Ion ◽  
Association Constants ◽  
Ion Binding ◽  
Ferric Uptake Regulator ◽  
Metal Ion Binding ◽  
Dimerization Domain ◽  
High Affinity

The functional properties of the recombinant C-terminal dimerization domain of the Pseudomonas aeruginosa Fur (ferric uptake regulator) protein expressed in and purified from Escherichia coli have been evaluated. Sedimentation velocity measurements demonstrate that this domain is dimeric, and the UV CD spectrum is consistent with a secondary structure similar to that observed for the corresponding region of the crystallographically characterized wild-type protein. The thermal stability of the domain as determined by CD spectroscopy decreases significantly as pH is increased and increases significantly as metal ions are added. Potentiometric titrations (pH 6.5) establish that the domain possesses a high-affinity and a low-affinity binding site for metal ions. The high-affinity (sensory) binding site demonstrates association constants (KA) of 10(±7)×106, 5.7(±3)×106, 2.0(±2)×106 and 2.0(±3)×104 M−1 for Ni2+, Zn2+, Co2+ and Mn2+ respectively, while the low-affinity (structural) site exhibits association constants of 1.3(±2)×106, 3.2(±2)×104, 1.76(±1)×105 and 1.5(±2)×103 M−1 respectively for the same metal ions (pH 6.5, 300 mM NaCl, 25 °C). The stability of metal ion binding to the sensory site follows the Irving–Williams order, while metal ion binding to the partial sensory site present in the domain does not. Fluorescence experiments indicate that the quenching resulting from binding of Co2+ is reversed by subsequent titration with Zn2+. We conclude that the domain is a reasonable model for many properties of the full-length protein and is amenable to some analyses that the limited solubility of the full-length protein prevents.

Bromine substituted aminonaphthoquinones: synthesis, characterization, DFT and metal ion binding studies

RSC Advances ◽  
2016 ◽  
Vol 6 (91) ◽  
pp. 88010-88029 ◽  
Author(s):  
Gunjan Agarwal ◽  
Dipali N. Lande ◽  
Debamitra Chakrovarty ◽  
Shridhar P. Gejji ◽  
Prajakta Gosavi-Mirkute ◽  
...  
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Ion Binding ◽  
Metal Ion Binding ◽  
Binding Studies

Bromine substituted aminonaphthoquinones – chemosensors for metal ions.

New multidentate ligands. XXI. Synthesis, proton, and metal ion binding affinities of N,N′,N″-tris[2-(N-hydroxycarbamoyl)ethyl]-1,3,5-benzenetricarboxamide (BAMTPH)

1983 ◽  
Vol 61 (12) ◽  
pp. 2740-2744 ◽  
Author(s):  
Isao Yoshida ◽  
Ichiro Murase ◽  
Ramunas J. Motekaitis ◽  
Arthur E. Martell
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Binding Constants ◽  
Cation Binding ◽  
Ion Binding ◽  
Binding Affinities ◽  
Metal Ion Binding ◽  
Trivalent Metal ◽  
Equilibrium Data ◽  
Trivalent Metal Ions

Synthesis of a new tris-bidentate multidentate ligand, N,N′,N″-tris[2-(N-hydroxycarbamoyl)ethyl]-1,3,5-benzenetricarboxamide (BAMTPH), designed for the binding of trivalent metal ions such as Fe(III), Ga(III), and Al(III), is described. Its cation binding affinities for hydrogen ion and for Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Ga(III), and Al(III) ions are described, and the equilibrium data are compared with those of analogous ligands. The binding constants of trivalent metal ions with the ligand do not show a chelate effect relative to the binding to individual bidentate hydroxamic acids.

scholarly journals Computational approaches for de novo design and redesign of metal-binding sites on proteins

2017 ◽  
Vol 37 (2) ◽  
Author(s):  
Gunseli Bayram Akcapinar ◽  
Osman Ugur Sezerman
Keyword(s):  
Metal Ions ◽  
Metal Binding ◽  
Binding Sites ◽  
Metal Ion ◽  
De Novo ◽  
De Novo Design ◽  
Ion Binding ◽  
Chemical Transformations ◽  
Metal Ion Binding ◽  
Metal Binding Sites

Metal ions play pivotal roles in protein structure, function and stability. The functional and structural diversity of proteins in nature expanded with the incorporation of metal ions or clusters in proteins. Approximately one-third of these proteins in the databases contain metal ions. Many biological and chemical processes in nature involve metal ion-binding proteins, aka metalloproteins. Many cellular reactions that underpin life require metalloproteins. Most of the remarkable, complex chemical transformations are catalysed by metalloenzymes. Realization of the importance of metal-binding sites in a variety of cellular events led to the advancement of various computational methods for their prediction and characterization. Furthermore, as structural and functional knowledgebase about metalloproteins is expanding with advances in computational and experimental fields, the focus of the research is now shifting towards de novo design and redesign of metalloproteins to extend nature’s own diversity beyond its limits. In this review, we will focus on the computational toolbox for prediction of metal ion-binding sites, de novo metalloprotein design and redesign. We will also give examples of tailor-made artificial metalloproteins designed with the computational toolbox.

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

scholarly journals Excitation-Energy Transfer Paths from Tryptophans to Coordinated Copper Ions in Engineered Azurins: a Source of Observables for Monitoring Protein Structural Changes

2016 ◽  
Vol 230 (9) ◽  
Author(s):  
Giulia Di Rocco ◽  
Fabrizio Bernini ◽  
Marco Borsari ◽  
Ilaria Martinelli ◽  
Carlo Augusto Bortolotti ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Excitation Energy ◽  
Metal Ions ◽  
Recombinant Proteins ◽  
Metal Ion ◽  
Structural Changes ◽  
Copper Ions ◽  
Excitation Energy Transfer ◽  
Ion Binding ◽  
Metal Ion Binding

AbstractThe intrinsic fluorescence of recombinant proteins offers a powerful tool to detect and characterize structural changes induced by chemical or biological stimuli. We show that metal-ion binding to a hexahistidine tail can significantly broaden the range of such structurally sensitive fluorescence observables. Bipositive metal-ions as Cu

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