title: Magnetosomes extracted from Magnetospirillum magneticum strain AMB-1 showed enhanced peroxidase-like activity under visible-light irradiation.
abstract: Magnetosomes are intracellular structures produced by magnetotactic bacteria and are magnetic nanoparticles surrounded by a lipid bilayer membrane. Magnetosomes reportedly possess intrinsic enzyme mimetic activity similar to that found in horseradish peroxidase (HRP) and can scavenge reactive oxygen species depending on peroxidase activity. Our previous study has demonstrated the phototaxis characteristics of Magnetospirillum magneticum strain AMB-1 cells, but the mechanism is not well understood. Therefore, we studied the relationship between visible-light irradiation and peroxidase-like activity of magnetosomes extracted from M. magneticum strain AMB-1. We then compared this characteristic with that of HRP, iron ions, and naked magnetosomes using 3,3',5,5'-tetramethylbenzidine as a peroxidase substrate in the presence of H2O2. Results showed that HRP and iron ions had different activities from those of magnetosomes and naked magnetosomes when exposed to visible-light irradiation. Magnetosomes and naked magnetosomes had enhanced peroxidase-like activities under visible-light irradiation, but magnetosomes showed less affinity toward substrates than naked magnetosomes under visible-light irradiation. These results suggested that the peroxidase-like activity of magnetosomes may follow an ordered ternary mechanism rather than a ping-pong mechanism. This finding may provide new insight into the function of magnetosomes in the phototaxis in magnetotactic bacteria.
authors.affiliation: Beijing Key Laboratory of Bioelectromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China; Shandong Sport University, Jinan 250102, China.
authors.forename: Kefeng
authors.initials: K
authors.lastname: Li
authors.affiliation: Beijing Key Laboratory of Bioelectromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China; France-China Bio-Mineralization and Nano-Structures Laboratory, Beijing 100193, China.
authors.forename: Chuanfang
authors.initials: C
authors.lastname: Chen
authors.affiliation: Beijing Key Laboratory of Bioelectromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Changyou
authors.initials: C
authors.lastname: Chen
authors.affiliation: Beijing Key Laboratory of Bioelectromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Yuzhan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Beijing Key Laboratory of Bioelectromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Zhao
authors.initials: Z
authors.lastname: Wei
authors.affiliation: Beijing Key Laboratory of Bioelectromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China; France-China Bio-Mineralization and Nano-Structures Laboratory, Beijing 100193, China.
authors.forename: Weidong
authors.initials: W
authors.lastname: Pan
authors.affiliation: Beijing Key Laboratory of Bioelectromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China; France-China Bio-Mineralization and Nano-Structures Laboratory, Beijing 100193, China. Electronic address: songtao@mail.iee.ac.cn.
authors.forename: Tao
authors.initials: T
authors.lastname: Song
mesh_terms: D006735:Horseradish Peroxidase / Q000378:metabolism / Q000528:radiation effects; D006861:Hydrogen Peroxide / Q000378:metabolism; D007501:Iron / Q000378:metabolism; D007700:Kinetics; D008027:Light; D055944:Magnetosomes / Q000378:metabolism* / Q000528:radiation effects; D042201:Magnetospirillum / Q000378:metabolism* / Q000528:radiation effects; D008954:Models, Biological; D010544:Peroxidases / Q000302:isolation & purification / Q000378:metabolism* / Q000528:radiation effects
chemical_list: D006861:Hydrogen Peroxide; D007501:Iron; D006735:Horseradish Peroxidase; D010544:Peroxidases
keywords: Light irradiation; Magnetosome; Peroxidase-like activity; Urea hydrogen peroxide