title: Antimicrobial activity and mechanism of action of a novel cationic α-helical dodecapeptide, a partial sequence of cyanate lyase from rice.
abstract: CL(14-25), a dodecapeptide, that is a partial region near N-terminus of cyanate lyase (CL, EC 4.3.99.1) from rice (Oryza sativa L. japonica), contains three arginine and two lysine residues. It was a novel cationic α-helical antimicrobial peptide. The antimicrobial activity of CL(14-25) against Porphyromonas gingivalis, a periodontal pathogen, was quantitatively evaluated by a chemiluminescence method that measures ATP derived from viable cells. The 50% growth-inhibitory concentration of CL(14-25) against P. gingivalis cells was 145 μM. CL(14-25), even at a concentration of 800 μM, had no hemolytic activity. When giant unilamellar vesicles (GUVs) that mimic the membrane composition of Gram-negative bacteria were used, microscopy image analysis suggested that CL(14-25) disrupted GUVs in a detergent-like manner. Therefore, CL(14-25) appears to exhibit antimicrobial activity through membrane disruption. To investigate the contribution of cationic amino acid residues in CL(14-25) to its antimicrobial activity, we synthesized four truncated CL analogs, in which one or two cationic amino acid residues were deleted from the N- and C- termini of CL(14-25). The degrees of calcein leakage from large unilamellar vesicles (LUVs) and 3,3'-dipropylthiadicarbocyanine iodide (diSC3-5) release from P. gingivalis cells induced by truncated CL analogs were closely related to their antimicrobial activities. CL analogs, which were truncated by removing an arginine residue from the N-terminus and a lysine residue from the C-terminus maintained their antimicrobial activity. However, CL analogs, which were further truncated by removing two arginine residues from the N-terminus, and an arginine and a lysine residue from the C-terminus, rarely exhibited antimicrobial activity.
authors.affiliation: Center for Fostering Innovative Leadership, Niigata University, Niigata 950-2181, Japan.
authors.forename: Norihiro
authors.initials: N
authors.lastname: Takei
authors.forename: Nobuteru
authors.initials: N
authors.lastname: Takahashi
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Takayanagi
authors.forename: Atsuo
authors.initials: A
authors.lastname: Ikeda
authors.forename: Kenji
authors.initials: K
authors.lastname: Hashimoto
authors.forename: Masahiro
authors.initials: M
authors.lastname: Takagi
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Hamada
authors.forename: Eiichi
authors.initials: E
authors.lastname: Saitoh
authors.forename: Akihito
authors.initials: A
authors.lastname: Ochiai
authors.forename: Takaaki
authors.initials: T
authors.lastname: Tanaka
authors.forename: Masayuki
authors.initials: M
authors.lastname: Taniguchi
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis / Q000378:metabolism; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry* / Q000494:pharmacology*; D019759:Carbon-Nitrogen Lyases / Q000737:chemistry*; D002462:Cell Membrane / Q000187:drug effects; D005452:Fluoresceins / Q000378:metabolism; D006090:Gram-Negative Bacteria / Q000187:drug effects; D006461:Hemolysis / Q000187:drug effects; D008163:Luminescent Measurements; D012275:Oryza / Q000737:chemistry*; D016966:Porphyromonas gingivalis / Q000187:drug effects; D012756:Sheep; D013329:Structure-Activity Relationship; D053835:Unilamellar Liposomes / Q000737:chemistry
chemical_list: D023181:Antimicrobial Cationic Peptides; D005452:Fluoresceins; D053835:Unilamellar Liposomes; D000255:Adenosine Triphosphate; C019953:cyanate hydrolase; D019759:Carbon-Nitrogen Lyases; C007740:fluorexon