scholarly journals Comparison of the sedimentation and gel-filtration behaviour of human apotransferrin and its copper and iron complexes

1973 ◽  
Vol 133 (4) ◽  
pp. 749-754 ◽  
Author(s):  
Peter A. Charlwood
Keyword(s):  
Metal Binding ◽  
Binding Sites ◽  
Equilibrium Dialysis ◽  
Gel Filtration ◽  
Sedimentation Velocity ◽  
Copper Binding ◽  
Metal Binding Sites ◽  
Stokes Radius ◽  
Effect Of Copper ◽  
Specific Metal

Equilibrium-dialysis experiments showed that Tris or citrate in the solution prevented copper from occupying completely the specific metal-binding sites on human transferrin. Differential measurements of sedimentation velocity under conditions where two atoms of copper per molecule of protein were bound showed an increase in s020,w, relative to that of the apoprotein, practically the same as that produced by two atoms of iron. Gel-filtration experiments made under the same conditions to investigate the effect of copper binding on the Stokes radius of the protein showed merely that it lost most of the metal as it passed down the column.

Supramolecular assembly of a hierarchically structured 3D potassium vanadate framework

CrystEngComm ◽  
2021 ◽  
Author(s):  
Simon Greiner ◽  
Montaha Anjass ◽  
Carsten Streb
Keyword(s):  
Solid State ◽  
Metal Binding ◽  
Binding Sites ◽  
Supramolecular Assembly ◽  
Metal Binding Sites ◽  
Solid State Materials ◽  
Specific Metal

We report how supramolecular host-guest assembly can be leveraged to close the gap between soluble polyoxometalates and functional solid-state materials. A polyoxovanadate cluster with specific metal binding sites is used...

scholarly journals Glutathione-mediated transfer of Cu(I) into phytochelatins

1995 ◽  
Vol 307 (3) ◽  
pp. 697-705 ◽  
Author(s):  
R K Mehra ◽  
P Mulchandani
Keyword(s):  
Metal Binding ◽  
Binding Sites ◽  
Room Temperature ◽  
Gel Filtration ◽  
Molar Ratio ◽  
Metal Binding Sites ◽  
Binding Stoichiometry ◽  
Metal Binding Peptides ◽  
Binding Peptides ◽  
Room Temperature Luminescence

Room temperature luminescence attributable to Cu(I)-thiolate clusters has been used to probe the transfer of Cu(I) from Cu(I)-glutathione complex to rabbit liver thionein-II and plant metal-binding peptides phytochelatins (gamma-Glu-Cys)2Gly, (gamma-Glu-Cys)3Gly and (gamma-Glu-Cys)4Gly. Reconstitutions were also performed using CuC1. The Cu(I)-binding stoichiometry of metallothionein or phytochelatins was generally independent of the Cu(I) donor. However, the luminescence of the reconstituted metallothionein or phytochelatins was higher when Cu(I)-GSH was the donor. This higher luminescence is presumably due to the stabilizing effect of GSH on Cu(I)-thiolate clusters. As expected, 12 Cu(I) ions were bound per molecule of metallothionein. The Cu(I) binding to phytochelatins depended on their chain length; the binding stoichiometries being 1.25, 2.0 and 2.5 for (gamma-Glu-Cys)2Gly, (gamma-Glu-Cys)3Gly and (gamma-Glu-Cys)4Gly respectively at neutral pH. A reduced stoichiometry for the longer phytochelatins was observed at alkaline pH. No GSH was found to associate with phytochelatins by a gel-filtration assay. The Cu(I) binding to (gamma-Glu-Cys)2Gly and (gamma-Glu-Cys)3Gly occurred in a biphasic manner in the sense that the relative luminescence increased approximately linearly with the amount of Cu(I) up to a certain molar ratio whereafter luminescence increased dramatically upon the binding of additional Cu(I). The luminescence intensity declined once the metal-binding sites were saturated. In analogy with the studies on metallothioneins, biphasic luminescence suggests the formation of two types of Cu(I) clusters in phytochelatins.

scholarly journals CheckMyMetal: a macromolecular metal-binding validation tool

2017 ◽  
Vol 73 (3) ◽  
pp. 223-233 ◽  
Author(s):  
Heping Zheng ◽  
David R. Cooper ◽  
Przemyslaw J. Porebski ◽  
Ivan G. Shabalin ◽  
Katarzyna B. Handing ◽  
...  
Keyword(s):  
Metal Binding ◽  
Binding Sites ◽  
Metal Ion ◽  
Data Bank ◽  
Biological Processes ◽  
Metal Binding Site ◽  
Metal Binding Sites ◽  
Metal Site ◽  
Validation Tool ◽  
Specific Metal

Metals are essential in many biological processes, and metal ions are modeled in roughly 40% of the macromolecular structures in the Protein Data Bank (PDB). However, a significant fraction of these structures contain poorly modeled metal-binding sites.CheckMyMetal(CMM) is an easy-to-use metal-binding site validation server for macromolecules that is freely available at http://csgid.org/csgid/metal_sites. TheCMMserver can detect incorrect metal assignments as well as geometrical and other irregularities in the metal-binding sites. Guidelines for metal-site modeling and validation in macromolecules are illustrated by several practical examples grouped by the type of metal. These examples showCMMusers (and crystallographers in general) problems they may encounter during the modeling of a specific metal ion.

scholarly journals Copper binding to the N-terminal metal-binding sites or the CPC motif is not essential for copper-induced trafficking of the human Wilson protein (ATP7B)

2006 ◽  
Vol 401 (1) ◽  
pp. 143-153 ◽  
Author(s):  
Michael A. Cater ◽  
Sharon La fontaine ◽  
Julian F. B. Mercer
Keyword(s):  
Metal Binding ◽  
Binding Sites ◽  
Site Directed Mutagenesis ◽  
Copper Binding ◽  
Phosphatase Domain ◽  
Copper Chelation ◽  
Metal Binding Sites ◽  
Excess Copper ◽  
Wilson Protein ◽  
P Type

The Wilson protein (ATP7B) is a copper-translocating P-type ATPase that mediates the excretion of excess copper from hep-atocytes into bile. Excess copper causes the protein to traffic from the TGN (trans-Golgi network) to subapical vesicles. Using site-directed mutagenesis, mutations known or predicted to abrogate catalytic activity (copper translocation) were introduced into ATP7B and the effect of these mutations on the intracellular traf-ficking of the protein was investigated. Mutation of the critical aspartic acid residue in the phosphorylation domain (DKTGTIT) blocked copper-induced redistribution of ATP7B from the TGN, whereas mutation of the phosphatase domain [TGE (Thr-Gly-Glu)] trapped ATP7B at cytosolic vesicular compartments. Our findings demonstrate that ATP7B trafficking is regulated with its copper-translocation cycle, with cytosolic vesicular localization associated with the acyl-phosphate intermediate. In addition, mut-ation of the six N-terminal metal-binding sites and/or the trans-membrane CPC (Cys-Pro-Cys) motif did not suppress the consti-tutive vesicular localization of the ATP7B phosphatase domain mutant. These results suggested that copper co-ordination by these sites is not essential for trafficking. Importantly, copper-chelation studies with these mutants clearly demonstrated a requirement for copper in ATP7B trafficking, suggesting the presence of an additional copper-binding site(s) within the protein. The results presented in this report significantly advance our understanding of the regulatory mechanism that links copper-translocation activity with copper-induced intracellular trafficking of ATP7B, which is central to hepatic and hence systemic copper homoeostasis.

scholarly journals Rational design of metal-binding sites in domain-swapped myoglobin dimers

2021 ◽  
Vol 217 ◽  
pp. 111374
Author(s):  
Satoshi Nagao ◽  
Ayaka Idomoto ◽  
Naoki Shibata ◽  
Yoshiki Higuchi ◽  
Shun Hirota
Keyword(s):  
Metal Binding ◽  
Binding Sites ◽  
Rational Design ◽  
Metal Binding Sites

scholarly journals Electron transfer pathways in photoexcited lanthanide(III) complexes of picolinate ligands

2021 ◽  
Author(s):  
Daniel Kovacs ◽  
Daniel Kocsi ◽  
Jordann A. L. Wells ◽  
Salauat R. Kiraev ◽  
Eszter Borbas
Keyword(s):  
Electron Transfer ◽  
Metal Binding ◽  
Binding Sites ◽  
Secondary Amide ◽  
Metal Binding Sites ◽  
Electron Transfer Pathways

A series of luminescent lanthanide(III) complexes consisting of 1,4,7-triazacyclononane frameworks and three secondary amide-linked carbostyril antennae were synthesised. The metal binding sites were augmented with two pyridylcarboxylate donors yielding octadentate...

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