A gain of superoxide dismutase (SOD) activity obtained with CCS, the copper metallochaperone for SOD1

Paul J. Schmidt, Minerva Ramos-Gomez, Valeria Cizewski Culotta

Research output: Contribution to journalArticlepeer-review

Abstract

The incorporation of copper ions into the cytosolic superoxide dismutase (SOD1) is accomplished in vivo by the action of the copper metallochaperone CCS (copper chaperone for SOD1). Mammalian CCS is comprised of three distinct protein domains, with a central region exhibiting remarkable homology (approximately 50% identity) to SOD1 itself. Conserved in CCS are all the SOD1 zinc binding ligands and three of four histidine copper binding ligands. In CCS the fourth histidine is replaced by an aspartate (Asp200). Despite this conservation of sequence between SOD1 and CCS, CCS exhibited no detectable SOD activity. Surprisingly, however, a single D200H mutation, targeting the fourth potential copper ligand in CCS, granted significant superoxide scavenging activity to this metallochaperone that was readily detected with CCS expressed in yeast. This mutation did not inhibit the metallochaperone capacity of CCS, and in fact, D200H CCS appears to represent a bifunctional SOD that can self-activate itself with copper. The aspartate at CCS position 200 is well conserved among mammalian CCS molecules, and we propose that this residue has evolved to preclude deleterious reactions involving copper bound to CCS.

Original languageEnglish (US)
Pages (from-to)36952-36956
Number of pages5
JournalJournal of Biological Chemistry
Volume274
Issue number52
DOIs
StatePublished - Dec 24 1999

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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