Cyanobacterial metallothionein gene expressed in Escherichia coli. Metal-binding properties of the expressed protein.
The recently isolated Synechococcus gene smtA encodes the only characterised prokaryotic protein designated to be a metallothionein (MT). To examine the metal-binding properties of its product the smtA gene was expressed in Escherichia coli as a carboxyterminal extension of glutathione-S-transferase. The pH of half dissociation of Zn, Cd and Cu ions from the expressed protein was determined to be 4.10, 3.50, 2.35, respectively, indicating a high affinity for these ions (in particular for Zn in comparison to mammalian MT). E. coli expressing this gene showed enhanced (ca. 3-fold) accumulation of Zn.
Shi
J
J
Department of Biological Sciences, University of Durham, UK.
Lindsay
W P
WP
Huckle
J W
JW
Morby
A P
AP
Robinson
N J
NJ
D000595:Amino Acid Sequence; D001483:Base Sequence; D002850:Chromatography, Gel; D003001:Cloning, Molecular; D000458:Cyanobacteria / Q000235:genetics*; D004269:DNA, Bacterial; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics*; D015870:Gene Expression; D006863:Hydrogen-Ion Concentration; D008668:Metallothionein / Q000235:genetics* / Q000378:metabolism; D008670:Metals / Q000378:metabolism; D008969:Molecular Sequence Data
D004269:DNA, Bacterial; D008670:Metals; D008668:Metallothionein