Synthesis of Peptide Analogs From Fish Venom With Potential Antimicrobial and Anticancer Activity

Grammistin Pp2a is a 13 amino acid peptide found in the venom of the fish Pogonoperca punctata. In this work, the wild type and 13 analogs of this peptide have been synthesized. A myristic acid chain has been added to the N-terminus of 7 peptide analogs. All peptides were tested for antibacterial, antifungal, anticancer, and hemolytic activities. Results show that most of the analogs have lower hemolytic activity than the natural peptide and the addition of myristic acid reduces its toxicity, except for the peptide with the highest net positive charge, MPp2a-O2K, which has a similar hemolytic activity as the natural peptide. The addition of the fatty chain also reduces solubility in aqueous media. Peptides with the most antifungal activity were Pp2A-EK and MPp2a-EK, both of which with a net negative charge, and Pp2a-NF, which had a truncated N-terminus with no fatty chain attached. Peptides with myristic acid chains showed significantly greater anticancer activity than those without modifications. However, the addition of free myristic acid into these peptide solutions did not improve their anti-cancer properties. Overall, this research contributes to the discovery and development of novel Grammistin Pp2a therapeutics with antibacterial, antifungal, and anticancer activities.