title: Characterization of the novel antibacterial peptide Leucrocin from crocodile (Crocodylus siamensis) white blood cell extracts.
abstract: Four novel antibacterial peptides, Leucrocin I-IV from Siamese crocodile white blood cell extracts were purified by reverse phase high performance liquid chromatography (RP-HPLC). Leucrocins exhibit strong antibacterial activity towards Staphylococcus epidermidis, Salmonella typhi and Vibrio cholerae. The peptides were 7-10 residues in length with different primary structure. The amino acid sequence of Leucrocin I is NGVQPKY with molecular mass around 806.99 Da and Leucrocin II is NAGSLLSGWG with molecular mass around 956.3 Da. Further, the interaction between peptides and bacterial membranes as part of their killing mechanism was studied by fluorescence and electron microscopy. The outer membrane and cytoplasmic membrane was the target of action of Leucrocins as assayed in model membrane by release of β-galactosidase due to the membrane permeabilization. Finally, the hemolytic effect was tested against human red blood cell. Leucrocin I, III and IV showed less toxicity against human red blood cells than Leucrocin II.
authors.affiliation: Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Supawadee
authors.initials: S
authors.lastname: Pata
authors.forename: Nualyai
authors.initials: N
authors.lastname: Yaraksa
authors.forename: Sakda
authors.initials: S
authors.lastname: Daduang
authors.forename: Yosapong
authors.initials: Y
authors.lastname: Temsiripong
authors.forename: Jisnuson
authors.initials: J
authors.lastname: Svasti
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Araki
authors.forename: Sompong
authors.initials: S
authors.lastname: Thammasirirak
mesh_terms: D000489:Alligators and Crocodiles / Q000276:immunology*; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000032:analysis* / Q000276:immunology* / Q000302:isolation & purification / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects / Q000648:ultrastructure; D002457:Cell Extracts / Q000737:chemistry; D006461:Hemolysis; D006801:Humans
chemical_list: D023181:Antimicrobial Cationic Peptides; D002457:Cell Extracts