Design, Synthesis and Evaluation of Antimicrobial Database-Derived Peptides Against Drug-Resistant Gram-Positive and Gram-Negative Pathogens

Bacterial drug resistance has become a serious problem worldwide as a consequence of long-term use and misuse of antibiotics. Current research trends indicate the development of anti-microbial peptides (AMPs) as a promising alternative to conventional antibiotics and to tackle antibiotic resistance. In the present work, novel short AMPs containing less than 15 amino acids with potential broad-spectrum activity are de-novo designed. A computational database-guided pipeline of rational analysis and modification is developed and utilized based on established principles of AMP activity such as charge, hydrophobicity, length, amino-acid frequency, charge density and hydrophobic moments. Potential broad-spectrum AMP sequences are designed based on a consecutive refinement strategy in which seed AMP sequences with desirable properties are predicted from scratch and then modified for possible improvement inactivity. Finally, four AMP sequences were designed, synthesized and tested for their efficacy in-vitro for broad spectrum anti-microbial activity against major drug resistant pathogens namely two Gram-positive organisms Staphylococcus aureus , Bacillus cereus and two Gram-negative pathogens Klebsiella aerogenes and Klebsiella pnuemoniae. Based on the inhibitory concentrations, two among the four designed peptides namely PEP01 (GKIMYILTKKS) and PEP03 (FGIKLRSVWKR) showed best results as broad-spectrum AMPs among which the sequence of PEP03 is further projected as a better candidate in terms of its predicted cell-penetrating and non-toxic nature.