De novo Design and Synthesis of Potent Antimicrobial Peptide and Mode of Action
Nualyai Yaraksa and Sakda Daduang* Author for corresponding; e-mail address: nualyai.y@ubru.ac.th
Volume: Vol.48 No.2 (March 2021)
Research Article
DOI:
Received: 11 March 2020, Revised: -, Accepted: 23 December 2020, Published: -
Citation: Yaraksa N. and Daduang S., De novo Design and Synthesis of Potent Antimicrobial Peptide and Mode of Action, Chiang Mai Journal of Science, 2021; 48(2): 444-459.
Abstract
As therapeutic potential, antimicrobial peptides (AMPs) with simple amino acid composition and short length can be effective candidates for clinical and commercial development. KL12, a 12-amino acid residual alpha-helical peptide with six-positive charges and 50% hydrophobicity, was designed by de novo design based on unique characteristics of naturally occurring AMPs, chemically synthesized by F-moc method and evaluated antimicrobial efficacy using broth microdilution assay. The antimicrobial experiments revealed that KL12 strongly inhibited the growth of human pathogenic bacteria. The analysis of minimum inhibitory concentrations (MICs) against Staphylococcus aureus ATCC25923, Staphylococcus saprophyticus ATCC15035, Staphylococcus aureus MRSA DMST20654, Salmonella typhi DMST22842 and Escherichia coli ATCC25922 showed that the MICs of KL12 were 2 μg/ml to 64 μg/ml. The modes of action of KL12 were investigated further on bacterial cell surface and membrane. Interaction with Lipopolysaccharide (LPS) and lipotheicoic acid (LTA) revealed that KL12 was able to bind and neutralize LPS and LTA. Fluorescence studies and electron microscopy analyzes indicated that KL12 killed bacterial cell by permeabilizing the cell membrane and damaging membrane integrity.