2026-10-13T18:51:14Z https://api.figshare.com/v2/oai

oai:figshare.com:article/32641302 2026-10-01T16:24:18Z portal_1172 item_type_8 month_year_10_2026

Rational design and bioactivity evaluation of antimicrobial peptides from the skin secretion of the frog, Pachymedusa dacnicolor Shiya Cheng (6593378) PUREID: 641881078 antimicrobial activity unnatural amino acid trypsin cleavage site Dermatoxin Medusin Antimicrobial peptides (AMPs) from the Mexican giant tree frog (Pachymedusa dacnicolor) are promising candidates for new antimicrobial agents. This study focuses on two AMP families—cationic QUB peptides and Medusin peptides—and an unusual anionic peptide, PD37. The novel AMP QUB3189 was used to design six analogues, revealing that shortening peptides reduced antimicrobial activity but lowered haemolysis, while increased α-helicity improved potency at the cost of higher cytotoxicity. Among them, QUB2578 showed strong broad-spectrum activity with minimal haemolysis. Medusin PD analogues modified with D-amino acids and non-natural residues improved activity, especially against Gram-negative bacteria, and reduced toxicity. In contrast, PD37, with a net charge of –2, had poor antimicrobial efficacy despite optimization but low toxicity. These results highlight the delicate balance of net charge, hydrophobicity, and α-helicity in AMP function and support rational design strategies for developing frog-derived AMPs as safe and effective therapeutics.<br><br><i>Thesis is embargoed until 31 July 2030.</i> 2026-10-01T16:24:18Z Text Thesis 10.17034/32641302.v1 https://figshare.com/articles/thesis/Rational_design_and_bioactivity_evaluation_of_antimicrobial_peptides_from_the_skin_secretion_of_the_frog_Pachymedusa_dacnicolor/32641302 All Rights Reserved Open Access after 2030-07-31