Copper environment in artificial metalloproteins probed by electron paramagnetic resonance spectroscopy

Flores, Marco, Olson, Tien L., Wang, Dong, Edwardraja, Selvakumar, Shinde, Sandip, Williams, JoAnn C., Ghirlanda, Giovanna and Allen, James P. (2015) Copper environment in artificial metalloproteins probed by electron paramagnetic resonance spectroscopy. Journal of Physical Chemistry B, 119 43: 13825-13833. doi:10.1021/acs.jpcb.5b04172


Author Flores, Marco
Olson, Tien L.
Wang, Dong
Edwardraja, Selvakumar
Shinde, Sandip
Williams, JoAnn C.
Ghirlanda, Giovanna
Allen, James P.
Title Copper environment in artificial metalloproteins probed by electron paramagnetic resonance spectroscopy
Journal name Journal of Physical Chemistry B   Check publisher's open access policy
ISSN 1520-5207
1520-6106
Publication date 2015-10-29
Sub-type Article (original research)
DOI 10.1021/acs.jpcb.5b04172
Open Access Status Not yet assessed
Volume 119
Issue 43
Start page 13825
End page 13833
Total pages 9
Place of publication Washington, DC, United States
Publisher American Chemical Society
Language eng
Abstract The design of binding sites for divalent metals in artificial proteins is a productive platform for examining the characteristics of metal–ligand interactions. In this report, we investigate the spectroscopic properties of small peptides and four-helix bundles that bind Cu(II). Three small peptides, consisting of 15 amino acid residues, were designed to have two arms, each containing a metal-binding site comprised of different combinations of imidazole and carboxylate side chains. Two four-helix bundles each had a binding site for a central dinuclear metal cofactor, with one design incorporating additional potential metal ligands at two identical sites. The small peptides displayed pH-dependent, metal-induced changes in the circular dichroism spectra, consistent with large changes in the secondary structure upon metal binding, while the spectra of the four-helix bundles showed a predominant α-helix content but only small structural changes upon metal binding. Electron paramagnetic resonance spectra were measured at X-band revealing classic Cu(II) axial patterns with hyperfine coupling peaks for the small peptides and four-helix bundles exhibiting a range of values that were related to the specific chemical natures of the ligands. The variety of electronic structures allow us to define the distinctive environment of each metal-binding site in these artificial systems, including the designed additional binding sites in one of the four-helix bundles.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: Institute for Molecular Bioscience - Publications
 
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Created: Fri, 21 Apr 2017, 11:44:01 EST by Selvakumar Edwardraja on behalf of Learning and Research Services (UQ Library)