Antimicrobial activity and mechanism of action of a novel cationic alpha-helical octadecapeptide derived from heat shock protein 70 of rice

作者：Taniguchi Masayuki^*; Ikeda Atsuo; Nakamichi Shun ichi; Ishiyama Yohei; Saitoh Eiichi; Kato Tetsuo; Ochiai Akihito; Tanaka Takaaki

来源：Peptides, 2013, 48: 147-155.

DOI：10.1016/j.peptides.2013.08.011

• Antimicrobial peptide
• Cationic alpha-helical peptide
• Porphyromonas gingivalis
• Candida albicans
• Membrane-active peptide

Hsp70(241-258), an octadecapeptide derived from the heat shock protein 70 (Hsp70) of rice (Oryza sativa L. japonica), is a novel cationic alpha-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 mu M and 70 mu M, respectively. Hsp70(241-258) had little or no hemolytic activity even at 1 mM, and showed negligible cytotoxicity up to 300 mu M. The degrees of calcein leakage from large unilamellar vesicles, which mimic the membranes of Gram-negative bacteria, and 3,3%26apos;-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.

• 出版日期2013-10