Cu/Zn superoxide dismutase can form pore-like structures

Mutations in Cu/Zn superoxide dismutase (SOD) are associated with familial amyotrophic lateral sclerosis (FALS), a neuro-degenerative disease that is characterized by the selective death of motor neurons. Despite the genetic association made between the protein and the disease, the mechanism by which the mutant SOD proteins become toxic is still a mystery. Using wild-type SOD and three pathogenic mutants (A4V, G37R, and G85R), we show that the copper-induced oxidation of metal-depleted SOD causes its in vitro aggregation into pore-like structures, as determined by atomic force microscopy. Because toxic pores have been recently implicated in the pathogenic mechanism of other neurodegenerative diseases, these results raise the possibility that the aberrant self-assembly of oxidatively damaged SOD mutants into toxic oligomers or pores may have a pathological role in FALS., (C) 2003 Elsevier Inc. All rights reserved.