Mn,Cd-metallothionein-2: a room temperature magnetic protein.
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.
Chang
Chia-Ching
CC
Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, 300, Taiwan. ccchang01@faculty.nctu.edu.tw
Lee
Shang-Fan
SF
Sun
Kein-Wen
KW
Ho
Chien-Chang
CC
Chen
Yu-Ting
YT
Chang
Cheng-Hung
CH
Kan
Lou-Sing
LS
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
D008668:Metallothionein