Triangular gold nanoparticles conjugated with peptide ligands: a new class of inhibitor for Candida albicans secreted aspartyl proteinase.

The aim of this study was to find the peptide ligands to inhibit Candida albicans secreted aspartyl proteinase 2 (Sap2). First, a ligand library, containing 300 different peptides, was constructed, and their interaction with Sap2 was separately calculated by molecular dynamic software. Second, 10 peptide ligands with the lowest intermolecular energy were selected. Then, triangular gold nanoparticles were synthesized, and separately conjugated with the peptide ligands. After synthesis, antifungal property and Sap inactivation of conjugated triangular gold nanoparticles, peptide ligands, and naked triangular gold nanoparticle were separately assessed, against thirty clinical isolates of C. albicans. In this study, we measured the uptake of conjugated and naked nanoparticles by atomic adsorption spectroscopy. This study showed that naked triangular gold nanoparticle and all conjugated triangular gold nanoparticles had high antifungal activity, but no peptide ligands had such activity. Of 300 peptide ligands, the peptide containing N-Cys-Lys-Lys-Arg-Met-Met-Lys-Ser-Met-Cys-C and its conjugate had the highest capability to inhibit Sap. Moreover, the uptake assay demonstrated that triangular gold nanoparticles conjugated with the peptide ligand had the highest uptake.