A significant future challenge for humanity is the rise of infectious disease epidemics stemming from bacterial antibiotic resistance. The Histatin family exhibits antimicrobial properties against drug-resistant strains and promotes wound healing. This study aimed to engineer a novel mutant of Histatin 3 to enhance its antimicrobial efficacy. Initially, molecular dynamics simulations of Histatin 3 were conducted in the presence of water molecules and ions, as well as a Sodium Dodecyl Sulfate (SDS) micelle, which serves as a model for bacterial membranes, using the GROMACS 5 software for a duration of 50 ns. Subsequently, to augment antibacterial properties, eight mutations were designed, and their structures were prepared, followed by individual MD simulations under the same conditions for each mutation. The binding free energy of the peptides with the SDS micelle was calculated using the MM/PBSA method. Ultimately, 950 ns MD simulation revealed that the D1A-G9W mutation exhibited the most favorable binding free energy to the SDS micelle, indicating enhanced interaction of this mutant with microbial membranes. Both this peptide and the wild-type Histatin 3 were synthesized, and their antimicrobial properties were assessed experimentally. The microbiological tests (MIC) on gram-negative and gram-positive stains demonstrated that this peptide was effective against gram-positive bacteria. The findings of this research suggest that, in designing mutations to enhance antimicrobial properties, attention should be given to both the reduction of negative charge and hydrophobicity.
