title: Requirements for antibacterial and hemolytic activities in the bovine neutrophil derived 13-residue peptide indolicidin.
abstract: The antimicrobial and hemolytic activities of the 13-residue peptide indolicidin (ILPWKWPWWPWRR-NH2), present in bovine neutrophils, and its analogs have been determined with a view to gaining insight into the structural roles of tryptophan and proline. Peptides where proline was replaced by alanine and tryptophan by phenylalanine showed antibacterial activities comparable to that of indolicidin. The peptides do not exhibit a strong propensity to occur in either helical or beta-sheet conformation. The peptides also do not appear to exert their activity by permeabilizing the bacterial plasma membrane unlike other endogenous antibacterial peptides. The presence of tryptophan appears to be essential for hemolytic activity as the phenylalanine analog does not exhibit any hemolytic activity.
authors.affiliation: Centre for Cellular and Molecular Biology, Hyderabad, India.
authors.forename: C
authors.initials: C
authors.lastname: Subbalakshmi
authors.forename: V
authors.initials: V
authors.lastname: Krishnakumari
authors.forename: R
authors.initials: R
authors.lastname: Nagaraj
authors.forename: N
authors.initials: N
authors.lastname: Sitaram
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides; D002175:Candida / Q000187:drug effects; D002417:Cattle; D002462:Cell Membrane; D002463:Cell Membrane Permeability; D004926:Escherichia coli / Q000187:drug effects; D006461:Hemolysis; D009504:Neutrophils / Q000737:chemistry*; D009994:Osmolar Concentration; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D011092:Polyethylene Glycols / Q000494:pharmacology; D011392:Proline / Q000502:physiology; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D051381:Rats; D013211:Staphylococcus aureus / Q000187:drug effects; D014364:Tryptophan / Q000502:physiology
chemical_list: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; D010455:Peptides; C073143:indolicidin; D011092:Polyethylene Glycols; D014364:Tryptophan; D011392:Proline