Figure 1.
Effect of MBI on Cu/ZnSOD fluorescence.
Conditions: Cu/ZnSOD: 3.0×10−6 molL−1; MBI/(×10−5 molL−1): (a) 0, (b) 1, (c) 2, (d) 3, (e) 4, (f) 5; (g): MBI (1×10−5 molL−1) + buffer (0.02 molL−1); pH 7.4; T = 293 K.
Figure 2.
Stern-Volmer plots for the quenching of Cu/ZnSOD by MBI at 293 and 310 K.
Table 1.
Stern-Volmer quenching constants for the interaction of MBI with Cu/ZnSOD at 293 K and 310 K.
Table 2.
Binding constants and relative thermodynamic parameters of the MBI-Cu/ZnSOD system.
Table 3.
Distance between MBI and the neighboring residues (6 Å involved).
Figure 3.
Docking results of the MBI and Cu/ZnSOD system.
(A) Binding site of MBI to Cu/ZnSOD. Two subdomains of Cu/ZnSOD are in different colors. (B) 2D structure of MBI with atom numbers. (C) Detailed illustration of the binding between MBI and Cu/ZnSOD. Hydrogen bonds are depicted as red dashed lines. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of the article).
Figure 4.
UV-vis spectra of Cu/ZnSOD in the presence of different concentrations of MBI (vs the same concentration of MBI solution).
Conditions: Cu/ZnSOD: 1.0×10−6 molL−1; MBI/(×10−5 molL−1): (a) 0, (b) 1, (c) 2, (d) 3; pH 7.4; T = 293 K.
Figure 5.
Synchronous fluorescence spectra of Cu/ZnSOD (A) Δλ = 15 nm and (B) Δλ = 60 nm.
Conditions: Cu/ZnSOD: 3.0×10−6 molL−1; MBI/(×10−5 molL−1): (a) 0, (b) 1, (c) 2, (d) 3, (e) 4, (f) 5; pH 7.4; T = 293 K.
Figure 6.
Quenching of Cu/ZnSOD synchronous fluorescence by MBI.
Conditions: Cu/ZnSOD: 3.0×10−6 molL−1; (○)Δλ = 15 nm and (▪) Δλ = 60 nm.
Figure 7.
CD spectra of MBI-Cu/ZnSOD system.
Conditions: Cu/ZnSOD: 5.0×10−7 molL−1; pH 7.4; T = 293 K.
Table 4.
Effects of MBI on the percentage of secondary structural elements in Cu/ZnSOD at 293 K.
Figure 8.
Effect of MBI on Cu/ZnSOD activity.
Cu/ZnSOD was exposed to graded concentrations of MBI for 60, 120 or 240 min. Conditions: Cu/ZnSOD: 3 nM. Data were pooled from at least three independent experiments and analyzed with one-way ANOVA. Error bars indicate SD.