title: Effect of substituting arginine and lysine with alanine on antimicrobial activity and the mechanism of action of a cationic dodecapeptide (CL(14-25)), a partial sequence of cyanate lyase from rice.
abstract: The antimicrobial activity of analogs obtained by substituting arginine and lysine in CL(14-25), a cationic α-helical dodecapeptide, with alanine against Porphyromonas gingivalis, a periodontal pathogen, varied significantly depending on the number and position of cationic amino acids. The alanine-substituted analogs had no hemolytic activity, even at a concentration of 1 mM. The antimicrobial activities of CL(K20A) and CL(K20A, K25A) were 3.8-fold and 9.1-fold higher, respectively, than that of CL(14-25). The antimicrobial activity of CL(R15A) was slightly lower than that of CL(14-25), suggesting that arginine at position 15 is not essential but is important for the antimicrobial activity. The experiments in which the alanine-substituted analogs bearing the replacement of arginine at position 24 and/or lysine at position 25 were used showed that arginine at position 24 was crucial for the antimicrobial activity whenever lysine at position 25 was substituted with alanine. Helical wheel projections of the alanine-substituted analogs indicate that the hydrophobicity in the vicinity of leucine at position 16 and alanines at positions 18 and/or 21 increased by substituting lysine at positions 20 and 25 with alanine, respectively. The degrees of diSC3 -5 release from P. gingivalis cells and disruption of GUVs induced by the alanine-substituted analogs with different positive charges were not closely related to their antimicrobial activities. The enhanced antimicrobial activities of the alanine-substituted analogs appear to be mainly attributable to the changes in properties such as hydrophobicity and amphipathic propensity due to alanine substitution and not to their extents of positive charge (cationicity).
authors: Department of Materials Science and Technology, Graduate School of Science and Technology, Niigata University, Niigata, 950-2181, Japan; Center for Transdisciplinary Research, Niigata University, Niigata, 950-2181, Japan.
authors: Masayuki
authors: M
authors: Taniguchi
authors: Nobuteru
authors: N
authors: Takahashi
authors: Tomohiro
authors: T
authors: Takayanagi
authors: Atsuo
authors: A
authors: Ikeda
authors: Yohei
authors: Y
authors: Ishiyama
authors: Eiichi
authors: E
authors: Saitoh
authors: Tetsuo
authors: T
authors: Kato
authors: Akihito
authors: A
authors: Ochiai
authors: Takaaki
authors: T
authors: Tanaka
mesh_terms: D000409:Alanine / Q000235:genetics*; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001120:Arginine / Q000235:genetics*; D052160:Benzothiazoles; D002232:Carbocyanines; D019759:Carbon-Nitrogen Lyases / Q000737:chemistry* / Q000494:pharmacology*; D002412:Cations; D006461:Hemolysis / Q000187:drug effects; D020128:Inhibitory Concentration 50; D008239:Lysine / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry / Q000494:pharmacology*; D012275:Oryza / Q000201:enzymology*; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology*; D016966:Porphyromonas gingivalis / Q000187:drug effects; D012756:Sheep; D013997:Time Factors; D053835:Unilamellar Liposomes / Q000737:chemistry
chemical_list: D000890:Anti-Infective Agents; D052160:Benzothiazoles; D002232:Carbocyanines; D002412:Cations; D009842:Oligopeptides; D010446:Peptide Fragments; D053835:Unilamellar Liposomes; C012944:3,3'-dipropyl-2,2'-thiadicarbocyanine; D001120:Arginine; C019953:cyanate hydrolase; C000606667:cyanate lyase (14-25), Oryza sativa; D019759:Carbon-Nitrogen Lyases; D008239:Lysine; D000409:Alanine
keywords: Porphyromonas gingivalis; alanine substitution; cationic antimicrobial peptide; giant unilamellar vesicle; membrane-active peptide