title: Sterilization mechanism of nitrogen gas plasma: induction of secondary structural change in protein.
abstract: The mechanism of action on biomolecules of N₂ gas plasma, a novel sterilization technique, remains unclear. Here, the effect of N₂ gas plasma on protein structure was investigated. BSA, which was used as the model protein, was exposed to N₂ gas plasma generated by short-time high voltage pulses from a static induction thyristor power supply. N₂ gas plasma-treated BSA at 1.5 kilo pulses per second showed evidence of degradation and modification when assessed by Coomassie brilliant blue staining and ultraviolet spectroscopy at 280 nm. Fourier transform infrared spectroscopy analysis was used to determine the protein's secondary structure. When the amide I region was analyzed in the infrared spectra according to curve fitting and Fourier self-deconvolution, N₂ gas plasma-treated BSA showed increased α-helix and decreased β-turn content. Because heating decreased α-helix and increased β-sheet content, the structural changes induced by N₂ gas plasma-treatment of BSA were not caused by high temperatures. Thus, the present results suggest that conformational changes induced by N₂ gas plasma are mediated by mechanisms distinct from heat denaturation.
authors.affiliation: Laboratory of Biometabolic Chemistry, School of Health Sciences, Faculty of Medicine, University of the Ryukyus, 1207 Uehara, Nishihara, Okinawa 903-0215, Japan. sakudo@med.u-ryukyu.ac.jp
authors.forename: Akikazu
authors.initials: A
authors.lastname: Sakudo
authors.forename: Masato
authors.initials: M
authors.lastname: Higa
authors.forename: Kojiro
authors.initials: K
authors.lastname: Maeda
authors.forename: Naohiro
authors.initials: N
authors.lastname: Shimizu
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Imanishi
authors.forename: Hideharu
authors.initials: H
authors.lastname: Shintani
mesh_terms: D002623:Chemistry Techniques, Analytical; D004202:Disinfectants / Q000494:pharmacology*; D009584:Nitrogen / Q000494:pharmacology*; D058626:Plasma Gases / Q000494:pharmacology*; D011487:Protein Conformation / Q000187:drug effects*; D011506:Proteins / Q000032:analysis / Q000737:chemistry*; D059748:Proteolysis / Q000187:drug effects; D013057:Spectrum Analysis; D013242:Sterilization / Q000379:methods*
chemical_list: D004202:Disinfectants; D058626:Plasma Gases; D011506:Proteins; D009584:Nitrogen
keywords: Fourier-transformed-infrared; bovine serum albumin; nitrogen gas plasma; static induction thyristor