RRC ID 3386
Author Jensen LT, Culotta VC.
Title Activation of CuZn superoxide dismutases from Caenorhabditis elegans does not require the copper chaperone CCS.
Journal J. Biol. Chem.
Abstract Reactive oxygen species are produced as the direct result of aerobic metabolism and can cause damage to DNA, proteins, and lipids. A principal defense against reactive oxygen species involves the superoxide dismutases (SOD) that act to detoxify superoxide anions. Activation of CuZn-SODs in eukaryotic cells occurs post-translationally and is generally dependent on the copper chaperone for SOD1 (CCS), which inserts the catalytic copper cofactor and catalyzes the oxidation of a conserved disulfide bond that is essential for activity. In contrast to other eukaryotes, the nematode Caenorhabditis elegans does not contain an obvious CCS homologue, and we have found that the C. elegans intracellular CuZn-SODs (wSOD-1 and wSOD-5) are not dependent on CCS for activation when expressed in Saccharomyces cerevisiae. CCS-independent activation of CuZn-SODs is not unique to C. elegans; however, this is the first organism identified that appears to exclusively use this alternative pathway. As was found for mammalian SOD1, wSOD-1 exhibits a requirement for reduced glutathione in CCS-independent activation. Unexpectedly, wSOD-1 was inactive even in the presence of CCS when glutathione was depleted. Our investigation of the cysteine residues that form the disulfide bond in wSOD-1 suggests that the ability of wSODs to readily form this disulfide bond may be the key to obtaining high levels of activation through the CCS-independent pathway. Overall, these studies demonstrate that the CuZn-SODs of C. elegans have uniquely evolved to acquire copper without the copper chaperone and this may reflect the lifestyle of this organism.
Volume 280(50)
Pages 41373-9
Published 2005-12-16
DOI 10.1074/jbc.M509142200
PII M509142200
PMID 16234242
MeSH Amino Acid Sequence Animals Caenorhabditis elegans Cell Line Copper / chemistry Dimerization Disulfides / chemistry Enzyme Activation Escherichia coli / metabolism Fungal Proteins / chemistry Glutathione / chemistry Glutathione / metabolism Humans Molecular Chaperones / chemistry Molecular Chaperones / physiology* Molecular Sequence Data Plasmids / metabolism Protein Binding Protein Structure, Tertiary Reactive Oxygen Species Saccharomyces cerevisiae / metabolism Sequence Homology, Amino Acid Superoxide Dismutase / metabolism*
IF 4.011
Times Cited 56
C.elegans tm776 tm1146