Fig. 3: Dissection of the effect of azurin on p53 ubiquitination.

a Highlighting the detailed interaction of azurin p28 region and p53-DBD. Residues involved in binding are labeled and shown as sticks. b Sequence conservation of residues at azurin p28 region involved in p53 binding. c In vitro ubiquitination assay of COP1-mediated p53 ubiquitination intervened by azurin. The reaction mixtures were incubated for 2 and 4 h, and then resolved by SDS-PAGE and immunoblotting assay with exclusive antibodies. d Effect of the affinity-disrupting mutants on ubiquitination level of p53 measured by ubiquitination assay. The designed mutants are azurin Q57R, T61R, M64E, G116E and A119E. Ctr represents p53 ubiquitination without any azurin treatment.