title: Strategies for stabilizing superoxide dismutase (SOD1), the protein destabilized in the most common form of familial amyotrophic lateral sclerosis.
abstract: Amyotrophic lateral sclerosis (ALS) is a disorder characterized by the death of both upper and lower motor neurons and by 3- to 5-yr median survival postdiagnosis. The only US Food and Drug Administration-approved drug for the treatment of ALS, Riluzole, has at best, moderate effect on patient survival and quality of life; therefore innovative approaches are needed to combat neurodegenerative disease. Some familial forms of ALS (fALS) have been linked to mutations in the Cu/Zn superoxide dismutase (SOD1). The dominant inheritance of mutant SOD1 and lack of symptoms in knockout mice suggest a "gain of toxic function" as opposed to a loss of function. A prevailing hypothesis for the mechanism of the toxicity of fALS-SOD1 variants, or the gain of toxic function, involves dimer destabilization and dissociation as an early step in SOD1 aggregation. Therefore, stabilizing the SOD1 dimer, thus preventing aggregation, is a potential therapeutic strategy. Here, we report a strategy in which we chemically cross-link the SOD1 dimer using two adjacent cysteine residues on each respective monomer (Cys111). Stabilization, measured as an increase in melting temperature, of ∼20 °C and ∼45 °C was observed for two mutants, G93A and G85R, respectively. This stabilization is the largest for SOD1, and to the best of our knowledge, for any disease-related protein. In addition, chemical cross-linking conferred activity upon G85R, an otherwise inactive mutant. These results demonstrate that targeting these cysteine residues is an important new strategy for development of ALS therapies.
authors.affiliation: Department of Chemistry and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, 415 South Street, Waltham, MA 02454, USA.
authors.forename: Jared R
authors.initials: JR
authors.lastname: Auclair
authors.forename: Kristin J
authors.initials: KJ
authors.lastname: Boggio
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Petsko
authors.forename: Dagmar
authors.initials: D
authors.lastname: Ringe
authors.forename: Jeffrey N
authors.initials: JN
authors.lastname: Agar
mesh_terms: D000690:Amyotrophic Lateral Sclerosis / Q000201:enzymology* / Q000235:genetics; D000818:Animals; D003432:Cross-Linking Reagents / Q000737:chemistry; D004220:Disulfides / Q000737:chemistry; D004795:Enzyme Stability; D006801:Humans; D008301:Maleimides / Q000737:chemistry; D051379:Mice; D015394:Molecular Structure; D009154:Mutation; D055503:Protein Multimerization; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013482:Superoxide Dismutase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000072105:Superoxide Dismutase-1
chemical_list: D003432:Cross-Linking Reagents; D004220:Disulfides; D008301:Maleimides; C000606290:SOD1 protein, human; D013438:Sulfhydryl Compounds; C043592:maleimide; C000606291:Sod1 protein, mouse; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1