Titration of Cupricyclin-1 with CuSO₄ monitored by ¹H NMR.

<p>The molar ratio CuSO₄/Cupricyclin-1 is reported on the left side of each spectrum.</p

<b>Table 2.</b> Superoxide dismutase activity of Cupriknottins.

<p><b>Table 2.</b> Superoxide dismutase activity of Cupriknottins.</p

EPR spectrum of Cupricyclins.

<p><b>Panel A shows the spectra of Cupricyclin-1 (Cc-1), Cupricyclin-2 (Cc-2) and a difference spectrum (diff) obtained by arbitrarily subtracting a fraction of Cc-1 from Cc-2.</b> Arrows on the first hyperfine of Cc-1 reveals the signal heterogeneity. Experimental details in the text. Panel B displays a detail of the perpendicular region of the difference spectrum, shown both as the standard first derivative lineshape and as the second derivative curve, to better evidence the superhyperfine lines due to interaction of copper with the four nitrogen nuclei of the coordinating histidine residues.</p

Optical spectra of apo and holo Cupricyclin-1 (0.6 mM in 50 mM sodium acetate buffer, pH 6.5).

<p>The difference spectrum is also shown to evidence the appearance of a band at 300–312 nm, indicative of a Cu²⁺-histidine charge-transfer <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030739#pone.0030739-Vita1" target="_blank">[21]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030739#pone.0030739-Cupane1" target="_blank">[22]</a>.</p

Assignments of ¹H and ¹³C resonances of apo-Cupriknottin 1 in D₂O at 300 K, pH 7.0.

<p>Letters a, b, c, d in the first column indicate the amino acid residues whose specific position in the peptide chains was not assigned.</p

Amino acid sequence of ω-conotoxin GVIA (A) and of the redesigned peptides Cupricyclin-1 (B) and Cupricyclin-2 (C), see below.

<p>Amino acid sequence of ω-conotoxin GVIA (A) and of the redesigned peptides Cupricyclin-1 (B) and Cupricyclin-2 (C), see below.</p

Amino acid sequence alignment of ω-conotoxins (A) and Weblogo [<b>17</b>] plot (B).

<p>The consensus sequence of the aligned ω-conotoxins is reported below the plot in panel B. The consensus sequence has been obtained by calculating the frequency of each amino acid in each position of the amino acid sequence of the aligned ω-conotoxin sequences using the Weblogo tool <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030739#pone.0030739-Crooks1" target="_blank">[17]</a>.</p