Metal-specific synthesis of two metallothioneins and gamma-glutamyl peptides in Candida glabrata.
Cellular resistance to heavy metal cytotoxicity in most species is mediated by the binding of metal ions either to a cysteine-rich polypeptide in the metallothionein family or to short cysteine-containing gamma-glutamyl peptides. One of these metal binding systems has been found in most organisms studied. However, the yeast Candida (Torulopsis) glabrata expresses both metallothionein and the gamma-glutamyl peptides for metal detoxification, and each system is regulated in a metal-specific manner. Exposure of C. glabrata to copper salts stimulates formation of two metallothionein-like polypeptides with a cysteine content of 30 mol% and the repeated sequence Cys-Xaa-Cys. The cells synthesize gamma-glutamyl peptides upon exposure to cadmium salts. Penta- and tetrapeptides that form a cadmium-thiolate cluster in a peptide oligomer containing labile sulfur are synthesized.
Mehra
R K
RK
Department of Medicine, University of Utah, Salt Lake City 84132.
Tarbet
E B
EB
Gray
W R
WR
Winge
D R
DR
D000595:Amino Acid Sequence; D002175:Candida / Q000378:metabolism*; D005971:Glutamates; D008163:Luminescent Measurements; D008668:Metallothionein / Q000096:biosynthesis* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D010452:Peptide Biosynthesis; D010455:Peptides / Q000302:isolation & purification; D013056:Spectrophotometry, Ultraviolet
D005971:Glutamates; D010455:Peptides; C004203:cadmium-binding protein; C007121:copper thionein; D008668:Metallothionein