The relationship between secondary structure of antimicrobial peptide and hydroxyl radical productions during bactericidal treatments

• Main Authors: Hsin-Ru Huang, 黃信儒
• Other Authors: Je-Wen Liou
• Format: Others
• Language: en_US
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/36075714495441591363

碩士 === 慈濟大學 === 微生物學免疫學暨生物化學研究所 === 99 === In order to combat the contentious developments of bacterial antibiotic resistance, searching and developing new antibacterial drugs has become a vital task for clinical applications. Antimicrobial peptides are one of the most important approaches for this purpose. Previous studies indicated that hydroxyl radical productions are the common mechanism during the antibiotic treatments of bacteria. Our research group also found that the antimicrobial peptides were also capable of induce the hydroxyl radical productions during the treatments, and this effect might be associated with the secondary structures of the peptides. This study attempted to link the secondary structure contents and the quantity of the hydroxyl radical productions during the antimicrobial treatments. Bioinfomatic approach was applied to predict the secondary structure contents of the mutant peptide derived from horseshoe crab Sushi 3 peptide via series of point mutations in its sequence. The predicted mutant peptides were chemically synthesized, and structurally examined using biophysical techniques Fourier transform infrared spectroscopy (FT-IR). The FTIR results indicated that the Sushi mutant I8G9A, G9A, I8G15P18A peptides had different helix contents, and the highly helix containing peptide I8G15P18A showed the best bactericidal ability. Peptides with higher helix contents also resulted in higher hydroxyl radical productions during bactericidal treatments as measured by 3’-(p-hydroxyphenyl) fluorescein dye and flowcytometry. The results of this study will provide valuable information for the design of new and effective antimicrobial peptides.