Fig. 3.

Resonance Raman analysis of Zn²⁺ binding to reduced Dcytb. a The low frequency region of the resonance Raman spectrum of Dcytb in the absence and presence of ZnCl₂ (5 mM) or ZnCl₂ (5 mM) and ascorbate (20 mM) are shown for the wild-type and H108Q variant proteins. b The titration of reduced wild-type Dcytb with Zn²⁺ as monitored by resonance Raman spectroscopy at 381 cm⁻¹. The peak areas at 381 cm⁻¹ are plotted as red circles as a function of [Zn²⁺]. The black curve represents a fit of the data to Eq. 2 to provide an estimated K_d of 0.5 ± 0.1 mM