Affiliation of Author(s):Harbin Institute of Technology
Journal:Journal of Hazardous Materials
Key Words:Heavy metal ions C-phycocyanin Light absorption Structure disorder
Abstract:This work has assessed the impact of typical heavy metal cations on C-phycocyanin in vitro and in silico. At low concentrations (<2×10 −6 mol/L), the influence of Pb 2+ is the highest on the light absorption of C-phycocyanin trimer. At higher concentrations, however, a new order of influence on the light absorption has been observed with Cd 2+ < Cu 2+ < Pb 2+ < Zn 2+ . The fluorescence polarization has changed from the order of Cd 2+ < Pb 2+ ≈Cu 2+ < Zn 2+ to Cd 2+ < Cu 2+ < Pb 2+ < Zn 2+ , when the metal concentrations reaches 2×10 −6 mol/ L. The mechanisms for these findings have been studied using FTIR, hydrophobic probe, isothermal titration calorimetry and molecular docking for the analysis of structure disorder of C-phycocyanin. It has been suggested that the secondary structure of C-phycocyanin affects more to the light absorbance while the fluorescence characteristics relies more on the tertiary structure. The interaction between Pb 2+ and C-phycocyanin is both enthalpically and entropically favoured, whereas the interactions for Cd 2+ , Cu 2+ and Zn 2+ are entropically driven. The ion-molecular docking suggests that the structure disorder of C-phycocyanin relies on the molecular interactions with metal ions. The in silico study also showed that the binding cites of Zn 2+ are closer to chro- mophores.
Volume:391
Issue:2020
Translation or Not:no
Links to published journals:https://doi.org/10.1016/j.jhazmat.2020.122225