Abstract
Palustrin-Ca (GFLDIIKDTGKEFAVKILNNLKCKLAGGCPP) is a host defence peptide with potent antimicrobial and anticancer activities, first isolated from the skin of the American bullfrog Lithobates catesbeianus. The peptide is 31 amino acid residues long, cationic and amphipathic. Two-dimensional NMR spectroscopy was employed to characterise its three-dimensional structure in a 50/50% water/2,2,2-trifluoroethanol-d_{3} mixture. The structure is defined by an alpha-helix that spans between Ile^{6}-Ala^{26}, and a cyclic disulfide-bridged domain at the C-terminal end of the peptide sequence, between residues 23 and 29. A molecular dynamics simulation was employed to model the peptide’s interactions with sodium dodecyl sulfate micelles, a widely used bacterial membrane-mimicking environment. Throughout the simulation, the peptide was found to maintain its alpha-helical conformation between residues Ile^{6}-Ala^{26}, while adopting a position parallel to the surface to micelle, which is energetically-favourable due to many hydrophobic and electrostatic contacts with the micelle.
Highlights
Palustrin-Ca (GFLDIIKDTGKEFAVKILNNLKCKLAGGCPP) is a host defence peptide with potent antimicrobial and anticancer activities, first isolated from the skin of the American bullfrog Lithobates catesbeianus
Host defence peptides (HDPs) are prevalent in amphibians, with approximately one-third of all known HDPs having been originally isolated from amphibians
As the number of documented cases of antimicrobial resistance to conventional small-molecule drugs continues to rise, interest in antimicrobial peptides (AMPs), which can exert their antimicrobial activity against both Gram-positive bacteria and Gram-negative bacteria without the development of resistance, continues to g row[6]
Summary
Palustrin-Ca (GFLDIIKDTGKEFAVKILNNLKCKLAGGCPP) is a host defence peptide with potent antimicrobial and anticancer activities, first isolated from the skin of the American bullfrog Lithobates catesbeianus. Host defence peptides (HDPs) are naturally occurring molecules that are secreted as part of the non-specific response of the innate immune s ystem[1]. AMPs possess a number of additional advantages They are more efficacious, selective and specific than small molecules, and are degraded to naturally occurring amino acids, which reduces the danger of unfavourable drugdrug interactions. A common feature of HDP structures is that they are typically amphipathic in nature, with a clear separation between the peptide’s hydrophobic and polar or charged residues. While HDPs are typically positively charged, anionic molecules such as lipopolysaccharides (LPS), phospholipids and teichoic acids are prevalent in prokaryotic cell membranes, which enables attractive electrostatic interactions between HDPs and their target bacterial cell membranes[19,20]. The cell membranes of cancer cells are enriched in negative charge, unlike non-cancerous cell membranes which are neutral, which allows anticancer peptides to be selectively electrostatically attracted to cancer cells
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
