Fig. 4: Copper interacts with the zinc finger motifs of Npl4. | Nature Communications

Fig. 4: Copper interacts with the zinc finger motifs of Npl4.

From: Seesaw conformations of Npl4 in the human p97 complex and the inhibitory mechanism of a disulfiram derivative

Fig. 4: Copper interacts with the zinc finger motifs of Npl4.

a Zinc finger motifs of Npl4 rescue the unfolding activity of p97 in the presence of cupric ions. b The initial velocity corresponds to panel a. The curves are presented as mean values ± SD from triplicate experiments. The error bars of the columns represent the SEM of the linear fitting. c HPLC profiles of synthesized ZF1 and ZF2 peptides mixed with fresh CuET (at 1:50 molar ratio) over 60 min. d HPLC profiles of synthesized ZF1 and ZF2 peptides mixed with cupric chloride at different ratios for 15 min. e A diagram showing the experimental steps of quantitative mass spectrometry using light and heavy formaldehyde to probe the interactions between cupric ions and the cysteine residues in the zinc finger motifs of Npl4. Cupric ions oxidize the cysteine residues of the zinc finger motifs and decrease the labeling percentage. f Results from the quantitative mass spectrometry (panel e). Labeled cysteine residues are highlighted in red. The first experiment was used as a control, in which both light and heavy labeling were treated with cupric ions, and the expected L/H ratio was 1.

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