Metal Ion Binding Properties of Perfluorosulfonate Membranes by Laser Excitation Spectroscopy

The metal ion binding properties of the perfluorosulfonate membrane Nafion® have been investigated in this study. The experiments involve laser-induced fluorescence measurements of europium (III) ions which are bound to the membrane. By the exploitation of the hypersensitivity of the D → F transitions of europium (III) to the ligand binding environment, the properties of the metal binding sites have been analyzed as a function of various experimental parameters. The spectra and fluorescence lifetime measurements provide evidence for distinct metal binding sites within the polymer, each of which is sensitive to the conditions of the membrane preparation.

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

Bioscience Reports ◽

10.1042/bsr20160179 ◽

2017 ◽

Vol 37 (2) ◽

Cited By ~ 12

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.

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Unravelling the Structure of the Tetrahedral Metal-Binding Site in METP3 through an Experimental and Computational Approach

Molecules ◽

10.3390/molecules26175221 ◽

2021 ◽

Vol 26 (17) ◽

pp. 5221

Author(s):

Salvatore La Gatta ◽

Linda Leone ◽

Ornella Maglio ◽

Maria De Fenza ◽

Flavia Nastri ◽

...

Keyword(s):

Metal Ions ◽

Binding Site ◽

Metal Binding ◽

Binding Sites ◽

Metal Ion ◽

Structural Determinants ◽

Binding Properties ◽

Tetrahedral Geometry ◽

Design Synthesis ◽

Metal Binding Sites

Understanding the structural determinants for metal ion coordination in metalloproteins is a fundamental issue for designing metal binding sites with predetermined geometry and activity. In order to achieve this, we report in this paper the design, synthesis and metal binding properties of METP3, a homodimer made up of a small peptide, which self assembles in the presence of tetrahedrally coordinating metal ions. METP3 was obtained through a redesign approach, starting from the previously developed METP molecule. The undecapeptide sequence of METP, which dimerizes to house a Cys4 tetrahedral binding site, was redesigned in order to accommodate a Cys2His2 site. The binding properties of METP3 were determined toward different metal ions. Successful assembly of METP3 with Co(II), Zn(II) and Cd(II), in the expected 2:1 stoichiometry and tetrahedral geometry was proven by UV-visible spectroscopy. CD measurements on both the free and metal-bound forms revealed that the metal coordination drives the peptide chain to fold into a turned conformation. Finally, NMR data of the Zn(II)-METP3 complex, together with a retrostructural analysis of the Cys-X-X-His motif in metalloproteins, allowed us to define the model structure. All the results establish the suitability of the short METP sequence for accommodating tetrahedral metal binding sites, regardless of the first coordination ligands.

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The 1H nuclear-magnetic-resonance spectroscopy of cobalt(II)-β-lactamase II

Biochemical Journal ◽

10.1042/bj1870789 ◽

1980 ◽

Vol 187 (3) ◽

pp. 789-795 ◽

Cited By ~ 7

Author(s):

A Galdes ◽

H A Hill ◽

G S Baldwin ◽

S G Waley ◽

E P Abraham

Keyword(s):

Metal Binding ◽

Metal Ion ◽

Marked Change ◽

Thiol Group ◽

Resonance Spectroscopy ◽

Ion Binding ◽

Metal Ion Binding ◽

Metal Binding Sites ◽

1H Nuclear Magnetic Resonance ◽

Beta Lactamase Ii

The 1H n.m.r. spectra of beta-lactamase II in the presence of Co(II) were studied. Analysis of the spectra suggests that Co(II) binds at the same two metal-binding sites as does Zn(II). The binding of Co(II) at the first site is much weaker than the binding of Zn(II) at this site, whereas the binding of Co(II) at the second site is tighter than the binding of Zn(II). The binding of Co(II) to the mono-zinc(II)-enzyme caused only one marked change in the spectrum, namely a decrease in the intensity of the resonances assigned to the C-2 and C-4 protons of one histidine residue (residue E). However, when the spectra of the apoenzyme and the Co(II)-enzyme were compared, there were many differences. A significant fraction of the protons in the whole molecule are affected by the binding of Co(II) at the first metal-ion-binding site (where the ligands are the enzyme's sole thiol group and three histidine residues). This may be because the first site is internal, or because of a difference in conformation between the apoenzyme and the mono-Co(II)-enzyme. The second site may be located on the surface of the molecule.

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Metal-binding sites of concanavalin A and their role in the binding of α-methyl d-glucopyranoside

Biochemical Journal ◽

10.1042/bj1090669 ◽

1968 ◽

Vol 109 (4) ◽

pp. 669-672 ◽

Cited By ~ 228

Author(s):

A. Joseph Kalb ◽

Alexander Levitzki

Keyword(s):

Transition Metal ◽

Concanavalin A ◽

Metal Binding ◽

Binding Sites ◽

Metal Ion ◽

Ion Binding ◽

Transition Metal Ion ◽

Metal Binding Sites ◽

Ion Binding Sites

Binding of a transition metal ion to specific sites in concanavalin A induces the formation of specific Ca2+ ion-binding sites. Sites for binding α-methyl d-glucopyranoside exist only when a transition metal ion and Ca2+ ion are bound.

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