Yeast copper-zinc superoxide dismutase can be activated in the absence of its copper chaperone.
Copper-zinc superoxide dismutase (Sod1) is an abundant intracellular enzyme that catalyzes the disproportionation of superoxide to give hydrogen peroxide and dioxygen. In most organisms, Sod1 acquires copper by a combination of two pathways, one dependent on the copper chaperone for Sod1 (CCS), and the other independent of CCS. Examples have been reported of two exceptions: Saccharomyces cerevisiae, in which Sod1 appeared to be fully dependent on CCS, and Caenorhabditis elegans, in which Sod1 was completely independent of CCS. Here, however, using overexpressed Sod1, we show there is also a significant amount of CCS-independent activation of S. cerevisiae Sod1, even in low-copper medium. In addition, we show CCS-independent oxidation of the disulfide bond in S. cerevisiae Sod1. There appears to be a continuum between CCS-dependent and CCS-independent activation of Sod1, with yeast falling near but not at the CCS-dependent end.
Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095-1569, USA, kevin.sea@pomona.edu.
Kevin W
KW
Sea
Yuewei
Y
Sheng
Herman L
HL
Lelie
Lindsay
L
Kane Barnese
Armando
A
Durazo
Joan Selverstone
JS
Valentine
Edith Butler
EB
Gralla
D003300:Copper / Q000378:metabolism*; D004789:Enzyme Activation; D010084:Oxidation-Reduction; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism*; D000072105:Superoxide Dismutase-1; D015032:Zinc / Q000378:metabolism
D003300:Copper; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; D015032:Zinc