The majority of amyotrophic lateral sclerosis (ALS)-related mutations in the enzyme Cu,Zn superoxide dismutase (SOD1), as well as a post-translational modification, glutathionylation, destabilize the protein and lead to a misfolded oligomer that is t ...
The majority of amyotrophic lateral sclerosis (ALS)-related mutations in the enzyme Cu,Zn superoxide dismutase (SOD1), as well as a post-translational modification, glutathionylation, destabilize the protein and lead to a misfolded oligomer that is toxic to motor neurons. The biophysical role of another physiological SOD1 modification, T2-phosphorylation, has remained a mystery. Here, we find that a phosphomimetic mutation, T2D, thermodynamically stabilizes SOD1 even in the context of a strongly SOD1-destabilizing mutation, A4V, one of the most prevalent and aggressive ALS-associated mutations in North America. This stabilization protects against formation of toxic SOD oligomers and positively impacts motor neuron survival in cellular assays. We solve the crystal structure of T2D-SOD1 and explain its stabilization effect using discrete molecular dynamics (DMD) simulations. These findings imply that T2-phosphorylation may be a plausible innate cellular protection response against SOD1-induced cytotoxicity, and stabilizing the SOD1 native conformation might offer us viable pharmaceutical strategies against currently incurable ALS.
Organizational Affiliation:
Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA; Program in Molecular and Cellular Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA; Curriculum in Bioinformatics and Computational Biology, University of North Carolina, Chapel Hill, NC 27599, USA.,Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA.,Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA; Program in Molecular and Cellular Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA.,Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA; Program in Molecular and Cellular Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA; Curriculum in Bioinformatics and Computational Biology, University of North Carolina, Chapel Hill, NC 27599, USA. Electronic address: dokh@unc.edu.
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