Study on the interaction between cyanobacteria FBP/SBPase and metal ions

Fructose-1,6-/sedoheptulose-1,7-bisphosphatase (FBP/SBPase) is a potential important target enzyme for finding inhibitors to solve harmful algal bloom. In this paper, the interactions between FBP/SBPase and metal ions were studied by enzyme activity analysis, fluorescence and molecular modeling method. The enzyme activity analysis showed that FBP/SBPase can be activated by Mg2+ or Mn2+ but cannot be activated by Ca2+ or Zn2+. Spectroscopic analysis of emission quenching showed that quenching mechanism of FBP/SBPase with Mg2+ or Mn2+ was static quenching mechanism while that of Ca2+ or Zn2+ was dynamic quenching process. Hydrogen bonds and van der Waals interaction might be the predominant intermolecular forces in stabilizing FBP/SBPase-Mg2+ while hydrophobic forces were the predominant intermolecular forces in stabilizing FBP/SBPase-Mn2+. Microenvironment and conformation of FBP/SBPase were changed in binding reaction. The effect of metal ions and important amino acid residues on FBP/SBPase–metal ion complex was also discussed by molecular modeling study.

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► We firstly present a detailed exploration of interaction between metal ions with cyanobacteria FBP/SBPase.
► FBP/SBPase can be activated by Mg2+ or Mn2+ by static quenching mechanism.
► Hydrogen bonds and van der Waals might be the predominant forces in stabilizing FBP/SBPase-ion2+ complexes.
► The effects of Mg2+ and Mn2+ on FBP/SBPase were due to the change of different α-helix or loop area.