Six structurally similar and strongly cationic peptides belonging to the brevinin-1 family were isolated from skin secretions of the plains leopard frog Lithobates blairi and the lowland leopard frog Lithobates yavapaiensis on the basis of their antimicrobial activities. Brevinin-1BLc (FLPIIAGIAAKFLPKIFCTISKKC) from L. blairi represented the most potent peptide (MIC = 25 μM Escherichia coli, MIC = 1.5 μM Staphylococcus aureus, MIC = 3 μM Candida albicans, LC50 = 9 μM human erythrocytes and LC50 = 6 μM HepG2 human hepatoma-derived cells). The appreciably lower antimicrobial potencies of brevinin-1Ya and -1Yc from L. yavapaiensis correlate with the decreases in cationicity produced by the amino acid substitutions Lys11 → Asn (brevinin-1Ya) and Pro14 → Glu (brevinin-1Yc). In addition, a peptide isolated from the skin secretions of L. yavapaiensis belonging to the ranatuerin-2 family (ranatuerin-2Ya; GLMDTIKGVAKTVAASWLDKLKCKIT GC) inhibited the growth of E. coli (MIC = 50 μM) and S. aureus (MIC = 50 μM). In contrast to brevinin-1BLc, ranatuerin-2Ya showed appreciably greater cytolytic activity against HepG2 cells (LC50 = 20 μM) than against erythrocytes (LC50 > 100 μM).
|Number of pages||7|
|Publication status||Published - Jun 2009|
- Antimicrobial peptide
- Frog skin
ASJC Scopus subject areas