title: Mn,Cd-metallothionein-2: a room temperature magnetic protein.
abstract: Naturally occurring metallothionein (MT) is a metal binding protein, which binds to seven Zn2+ through 20 conserved cysteines and forms two metal binding clusters with a Zinc-Blende structure. We demonstrate that the MT, when substituting the Zn2+ ions by Mn2+ and Cd2+, exhibits magnetic hysteresis loop observable by SQUID from 10 to 330 K. The magnetic moment may have originated from the bridging effect of the sulfur atoms between the metal ions that leads to the alignment of the electron spins of the Mn2+ ions inside the clusters. The protein backbone may restrain the net spin moment of Mn2+ ions from thermal fluctuation. The modified magnetic-metallothionein is a novel approach to creating molecular magnets with operating temperatures up to 330 K.
authors.affiliation: Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, 300, Taiwan. ccchang01@faculty.nctu.edu.tw
authors.forename: Chia-Ching
authors.initials: CC
authors.lastname: Chang
authors.forename: Shang-Fan
authors.initials: SF
authors.lastname: Lee
authors.forename: Kein-Wen
authors.initials: KW
authors.lastname: Sun
authors.forename: Chien-Chang
authors.initials: CC
authors.lastname: Ho
authors.forename: Yu-Ting
authors.initials: YT
authors.lastname: Chen
authors.forename: Cheng-Hung
authors.initials: CH
authors.lastname: Chang
authors.forename: Lou-Sing
authors.initials: LS
authors.lastname: Kan
mesh_terms: D000818:Animals; D003198:Computer Simulation; D004574:Electromagnetic Fields; D008099:Liver / Q000737:chemistry*; D008280:Magnetics; D008668:Metallothionein / Q000737:chemistry* / Q000528:radiation effects / Q000648:ultrastructure*; D008958:Models, Molecular; D011487:Protein Conformation / Q000528:radiation effects; D011817:Rabbits; D013329:Structure-Activity Relationship; D013696:Temperature
chemical_list: D008668:Metallothionein