Figure 2. CD spectra of zinc hook peptides recorded in 10 mM Tris-HCl buffer, 100 mM NaClO₄, 100–200 μM TCEP, pH 7.4.

(a) Titrations of Hk4, Hk8, Hk14, and Hk45 with Zn²⁺ ions. The insets show the dependence of ellipticity at 220 nm on the Zn²⁺/Hk molar ratio. Red and blue colors refer to spectra of metal-free hook peptides and Zn(Hk)₂ complexes, respectively; (b) Differential CD spectra of the zinc hook peptides obtained by the subtraction of spectra of free peptides from the spectra of Zn(Hk)₂ complexes.