NDLI: $Zn^{II}$ and $Hg^{II}$ binding to a designed peptide that accommodates different coordination geometries

Content Provider	World Health Organization (WHO)-Global Index Medicus
Author	Szunyogh, Dániel Larsen, Flemming H. Thulstrup, Peter W. Jancsó, Attila Stachura, Monika Gyurcsik, Béla Hemmingsen, Lars
Description	Author Affiliation: Szunyogh D ( MTA-SZTE Bioinorganic Chemistry Research Group, Dóm tér 7, Szeged, H-6720, Hungary.)
Abstract	Designed metal ion binding peptides offer a variety of applications in both basic science as model systems of more complex metalloproteins, and in biotechnology, e.g. in bioremediation of toxic metal ions, biomining or as artificial enzymes. In this work a peptide (HS: $Ac-SCHGDQGSDCSI-NH_{2})$ has been specifically designed for binding of both $Zn^{II}$ and $Hg^{II},$ i.e. metal ions with different preferences in terms of coordination number, coordination geometry, and to some extent ligand composition. It is demonstrated that HS accommodates both metal ions, and the first coordination sphere, metal ion exchange between peptides, and speciation are characterized as a function of pH using UV-absorption-, synchrotron radiation CD-, $^{1}H-NMR-,$ and PAC-spectroscopy as well as potentiometry. $Hg^{II}$ binds to the peptide with very high affinity in a $\{HgS_{2}\}$ coordination geometry, bringing together the two cysteinates close to each end of the peptide in a loop structure. Despite the high affinity, $Hg^{II}$ is kinetically labile, exchanging between peptides on the subsecond timescale, as indicated by line broadening in $^{1}H-NMR.$ The $Zn^{II}-HS$ system displays more complex speciation, involving monomeric species with coordinating cysteinates, histidine, and a solvent water molecule, as well as $HS-Zn^{II}-HS$ complexes. In summary, the HS peptide displays conformational flexibility, contains many typical metal ion binding groups, and is able to accommodate metal ions with different structural and ligand preferences with high affinity. As such, the HS peptide may be a scaffold offering binding of a variety of metal ions, and potentially serve for metal ion sequestration in biotechnological applications.
ISSN	14779226
Issue Number	28
Volume Number	44
e-ISSN	13645447
Journal	Dalton Trans.
Language	English
Publisher	Royal Society of Chemistry
Publisher Date	2015-07-28
Publisher Place	Great Britain (UK)
Access Restriction	Subscribed
Subject Keyword	Coordination Complexes Chemistry Mercury Oligopeptides Zinc Circular Dichroism Ligands Magnetic Resonance Spectroscopy Potentiometry Journal Article Research Support, Non-U.S. Gov't
Content Type	Text
Resource Type	Article
Subject	Inorganic Chemistry

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