Copper replacement of cadmium-binding alpha-fragment of metallothionein expressed in Escherichia coli.
Titration studies of Cd-binding alpha-fragment, the carboxyl-terminal half of human metallothionein-2, which was independently expressed in Escherichia coli as a Cd-binding form, with Cu were performed. The Cu saturated alpha-fragment was not obtained when the alpha-fragment incubated with Cu (I), although completely saturated MT with Cu (I) was successfully obtained in the same conditions. The stoichiometry of the alpha-fragment replaced with Cu (I) was Cu 4 and Cd 1. It is considered that the Cu-binding alpha-fragment required the presence of Cd (II) to form a stable structure. Our results could suggest that each fragment was independent in the metal binding processes, e.g. alpha-fragment for Cd-binding.
Kurasaki
M
M
Department of Environmental Medicine and Informatics, Graduate School of Environmental Earth Science, Hokkaido University, Sapporo, Japan.
Yamasaki
F
F
Suzuki-Kurasaki
M
M
Kojima
Y
Y
D001665:Binding Sites; D002352:Carrier Proteins / Q000378:metabolism; D003300:Copper / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism*; D006801:Humans; D008668:Metallothionein / Q000096:biosynthesis / Q000378:metabolism*; D010446:Peptide Fragments / Q000096:biosynthesis / Q000378:metabolism*
D002352:Carrier Proteins; D010446:Peptide Fragments; C004203:cadmium-binding protein; C007121:copper thionein; C023548:copper-binding protein; D003300:Copper; D008668:Metallothionein