title: Antimicrobial activity and mechanism of action of a novel cationic α-helical octadecapeptide derived from heat shock protein 70 of rice.
abstract: Hsp70(241-258), an octadecapeptide derived from the heat shock protein 70 (Hsp70) of rice (Oryza sativa L. japonica), is a novel cationic α-helical antimicrobial peptide (AMP) that contains four lysine, two arginine, and two histidine residues. The antimicrobial activity of Hsp70(241-258) against Porphyromonas gingivalis, a periodontal pathogen, and Candida albicans, an opportunistic fungal pathogen, was quantitatively evaluated using a chemiluminescence method that measures ATP derived from viable cells. The 50% growth-inhibitory concentrations of Hsp70(241-258) against P. gingivalis and C. albicans cells were 63 μM and 70 μM, respectively. Hsp70(241-258) had little or no hemolytic activity even at 1mM, and showed negligible cytotoxicity up to 300 μM. The degrees of calcein leakage from large unilamellar vesicles, which mimic the membranes of Gram-negative bacteria, and 3,3'-dipropylthiadicarbocyanine iodide release from P. gingivalis cells induced by the addition of Hsp70(241-258) increased in a concentration-dependent manner. When Hsp70(241-258) was added to calcein-acetoxymethyl ester-loaded C. albicans cells, calcein release from the cells increased in a concentration-dependent manner. Flow cytometric analysis also showed that the percentages of C. albicans cells stained with propidium iodide, a DNA-intercalating dye, increased as the concentration of Hsp70(241-258) added was increased. Therefore, Hsp70(241-258) appears to exhibit antimicrobial activity against P. gingivalis and C. albicans through membrane disruption. These results suggest that Hsp70(241-258) could be useful as a safe and potent AMP against P. gingivalis and C. albicans in many fields of health care, especially in the control of oral infections.
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. Electronic address: mtanig@eng.niigata-u.ac.jp.
authors: Masayuki
authors: M
authors: Taniguchi
authors: Atsuo
authors: A
authors: Ikeda
authors: Shun-Ichi
authors: S
authors: Nakamichi
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: D000595:Amino Acid Sequence; D000890:Anti-Infective Agents / Q000737:chemistry / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000494:pharmacology*; D002176:Candida albicans / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D005434:Flow Cytometry; D005882:Gingival Diseases / Q000188:drug therapy; D018840:HSP70 Heat-Shock Proteins / Q000737:chemistry / Q000494:pharmacology*; D006461:Hemolysis; D006801:Humans; D012275:Oryza / Q000737:chemistry; D016966:Porphyromonas gingivalis / Q000187:drug effects*; D013329:Structure-Activity Relationship
chemical_list: D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; D018840:HSP70 Heat-Shock Proteins
keywords: Antimicrobial peptide; Candida albicans; Cationic α-helical peptide; Membrane-active peptide; Porphyromonas gingivalis