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Issue 8, 2019
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Emerging investigator series: characterization of silver and silver nanoparticle interactions with zinc finger peptides

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Abstract

In biological systems, chemical and physical transformations of engineered silver nanomaterials (AgENMs) are mediated, in part, by proteins and other biomolecules. Metalloprotein interactions with AgENMs are also central in understanding toxicity, antimicrobial, and resistance mechanisms. Despite their readily available thiolate and amine ligands, zinc finger (ZF) peptides have thus far escaped study in reaction with AgENMs and their Ag(I) oxidative dissolution product. We report spectroscopic studies that characterize AgENM and Ag(I) interactions with two ZF peptides that differ in sequence, but not in metal binding ligands: the ZF consensus peptide CP-CCHC and the C-terminal zinc finger domain of HIV-1 nucleocapsid protein p7 (NCp7_C). Both ZF peptides catalyze AgENM (10 and 40 nm, citrate coated) dissolution and agglomeration, two important AgENM transformations that impact bioreactivity. AgENMs and their oxidative dissolution product, Ag(I)(aq), mediate changes to ZF peptide structure and metalation as well. Spectroscopic titrations of Ag(I) into apo-ZF peptides show an Ag(I)–thiolate charge transfer band, indicative of Ag(I)–ZF binding. Fluorescence studies of the Zn(II)–NCp_7 complex indicate that the Ag(I) also effectively competes with the Zn(II) to drive Zn(II) displacement from the ZFs. Upon interaction with AgENMs, Zn(II) bound ZF peptides show a secondary structural change in circular dichroism spectroscopy toward an apo-like structure. The results suggest that Ag(I) and AgENMs may alter ZF protein function within the cell.

Graphical abstract: Emerging investigator series: characterization of silver and silver nanoparticle interactions with zinc finger peptides

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Article information


Submitted
16 Jan 2019
Accepted
10 Jul 2019
First published
19 Jul 2019

Environ. Sci.: Nano, 2019,6, 2367-2378
Article type
Paper
Author version available

Emerging investigator series: characterization of silver and silver nanoparticle interactions with zinc finger peptides

G. Park, Z. N. Amaris, M. K. Eiken, K. V. Baumgartner, K. A. Johnston, M. A. Williams, J. G. Marckwordt, J. E. Millstone, K. E. Splan and K. E. Wheeler, Environ. Sci.: Nano, 2019, 6, 2367
DOI: 10.1039/C9EN00065H

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