A novel antimicrobial peptide derived from membrane-proximal external region of human immunodeficiency virus type 1

• Novel peptide AP16-A from membrane-proximal external region of HIV-1 is described.
• AP16-A shows antimicrobial activities against Gram-negative and -positive bacteria.
• AP16-A is safe in eukaryocytic cells.
• AP16-A kills Gram-negative bacteria and -positive bacteria by different mechanisms.

With increasing microbial drug resistance worldwide, antimicrobial peptides (AMPs) are considered promising alternatives to addressing this problem. In this study, a series of synthetic peptides were designed based on the membrane-disrupting properties of the membrane-proximal external region (MPER) of human immunodeficiency virus type 1 (HIV-1) envelope protein. The peptide AP16-A was found to exhibit the most effective antimicrobial activities against both Gram-negative and Gram-positive bacteria. The minimal bactericidal concentration (MBC) of AP16-A ranged from 2 μg/ml to 16 μg/ml. AP16-A had no detectable cytotoxicity in various tissue cultures and a mouse model. Furthermore, results of confocal fluorescence microscopy and the SYTOX Green uptake assay indicated that AP16-A killed Gram-negative bacteria by the combined effects of relatively slow membrane permeabilization and interaction with an intracellular target, while it killed Gram-positive bacteria by a fast membrane permeabilization process, which achieved relatively more rapid bacterial killing kinetics. The results of this study support the potential use of AP16-A as an AMP.