title: Peptides with potent cytolytic activity from the skin secretions of the North American leopard frogs, Lithobates blairi and Lithobates yavapaiensis.
abstract: 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=25microM Escherichia coli, MIC=1.5microM Staphylococcus aureus, MIC=3microM Candida albicans, LC(50)=9microM human erythrocytes and LC(50)=6microM 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 Lys(11)-->Asn (brevinin-1Ya) and Pro(14)-->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=50microM) and S. aureus (MIC=50microM). In contrast to brevinin-1BLc, ranatuerin-2Ya showed appreciably greater cytolytic activity against HepG2 cells (LC(50)=20microM) than against erythrocytes (LC(50)>100microM).
authors.affiliation: Department of Biochemistry, Faculty of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates. jmconlon@uaeu.ac.ae
authors.forename: J Michael
authors.initials: JM
authors.lastname: Conlon
authors.forename: Eman
authors.initials: E
authors.lastname: Ahmed
authors.forename: Laurent
authors.initials: L
authors.lastname: Coquet
authors.forename: Thierry
authors.initials: T
authors.lastname: Jouenne
authors.forename: Jérôme
authors.initials: J
authors.lastname: Leprince
authors.forename: Hubert
authors.initials: H
authors.lastname: Vaudry
authors.forename: Jay D
authors.initials: JD
authors.lastname: King
mesh_terms: D029845:Amphibian Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D000818:Animals; D000890:Anti-Infective Agents / Q000737:chemistry / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology*; D002176:Candida albicans / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D004926:Escherichia coli / Q000187:drug effects; D006801:Humans; D008826:Microbial Sensitivity Tests; D009656:North America; D010455:Peptides / Q000737:chemistry / Q000494:pharmacology*; D011898:Ranidae / Q000502:physiology*; D012867:Skin / Q000737:chemistry* / Q000378:metabolism; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D029845:Amphibian Proteins; D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; D000970:Antineoplastic Agents; D010455:Peptides; C078413:brevinin-1 protein, Rana