Identification of a high-molecular-weight cadmium-binding protein in copper-resistant Bacillus acidocaldarius cells.
Bacillus acidocaldarius grown in the presence of Cu++ was capable of accumulating the metal in the form of a protease-sensitive high molecular weight (HMW) moiety whose formation was inhibited by actinomycin D. Only cells preadapted in Cu++ were able to grow in a Cd(++)-containing medium. A cell-free extract from cadmium-stressed cells was fractionated by gel-permeation chromatography. The majority of cadmium was found associated with a HMW protein fraction which was further purified by anion exchange chromatography and high-performance liquid chromatography. The molecular weight of the purified protein was estimated to be 23,000 by SDS-PAGE. Amino acid analysis showed a low cysteine content and an abundance of aspartate and glutamate. It is likely that the cadmium-binding protein is an essential component of the mechanism mediating recovery from heavy metal toxicity.
Capasso
C
C
C.N.R. Institute of Protein Biochemistry and Enzymology, Napoli, Italy.
Nazzaro
F
F
Marulli
F
F
Capasso
A
A
La Cara
F
F
Parisi
E
E
D000596:Amino Acids / Q000032:analysis; D001407:Bacillus / Q000187:drug effects* / Q000254:growth & development; D002104:Cadmium / Q000494:pharmacology*; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003300:Copper / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D066298:In Vitro Techniques; D008667:Metalloproteins / Q000737:chemistry / Q000302:isolation & purification*
D000596:Amino Acids; D008667:Metalloproteins; D002104:Cadmium; D003300:Copper