DFT-based Analysis of Siderophore-Metal Ion Interaction for Efficient Heavy Metal Remediation

Abstract

Abstract Siderophores have great application potential in metal pollutant remediation because of their effective cost and friendly impact on the environment. However, the practical use of siderophores in the remediation of specific metals is rather limited because of the weak nonspecific interactions between the siderophores and different metals. Thus, screening for a siderophore with optimal interaction with a specific metal would be necessary. Here, the interaction between metal ions and moieties that donate the oxygen ligands for the coordination of four types of siderophore (hydroxamates, catecholates, phenolates and carboxylates) was modeled and analyzed. As revealed by DFT-based analysis, the four types of siderophore generally exhibited selection preference for different metal ions in the order Ga3+ > Al3+ > Fe3+ > Cr3+ > Ni2+ > Cu2+ > Zn2+ > Co2+ > Mn2+ > Hg2+ > Pb2+ > Cd2+, which was determined mainly by the electronegativity of both siderophore functional groups and metals, and of the ionic radius of the metals, as well as the interaction between the main chain of the siderophore and the metals. Moreover, the effect of linear or nonlinear (cyclic) structure on the affinity of the siderophore for different metal ions was evaluated. In most situations, metal-bound cyclic siderophores are more stable than their linear counterparts. Thus, proper siderophores for the remediation of metal pollution may be rapidly screened using the model.