Study of metal-lipopeptide complexes and their self-assembly behavior, micelle formation, interaction with bovine serum albumin and biological properties

Abstract

The present study aimed to explore the interactions of divalent counterions with biomolecular amphisin using circular dichroism (CD), ultravioletvisible (UVVis) and density functional theory (DFT). The binding mode of interactions between metal-amphisin complexes and bovine serum albumin (BSA) were studied using fluorescence spectroscopy. The results showed that Cu2+ is coordinated by one oxygen atom of the aspartic acid side chain and three amide nitrogen atoms, whereas Zn2+, Ca2+ and Mg2+ favour the association with backbone oxygen atoms of the amphisin. On the other hand, the aggregation of amphisin induced by divalent counterions was studied by dynamic light scattering (DLS). Our results revealed that the self-assembly process of amphisin can be controlled by the addition of metal ions. The results of CD spectra demonstrated that the binding of divalent counterions to the lipopeptide induces conformational changes in amphisin. Further studies using fluorescence spectroscopy showed that the metal-lipopeptide systems could interact with some functional groups of BSA, increasing the microenvironment around Trp residues of BSA. Thus, the interaction data acquired herein for the interesting class of complexes will be of significance in metal-based drug discovery and developmental research.