Functional features cause misfolding of the ALS-provoking enzyme SOD1

Research output: Contribution to journalArticle

Abstract

The structural integrity of the ubiquitous enzyme superoxide dismutase (SOD1) relies critically on the correct coordination of Cu and Zn. Loss of these cofactors not only promotes SOD1 aggregation in vitro but also seems to be a key prerequisite for pathogenic misfolding in the neurodegenerative disease amyotrophic lateral sclerosis (ALS). We examine here the consequences of Zn2+ loss by selectively removing the Zn site, which has been implicated as the main modulator of SOD1 stability and disease competence. After Zn-site removal, the remaining Cu ligands can coordinate a non-native Zn2+ ion with mu M affinity in the denatured state, and then retain this ion throughout the folding reaction. Without the restriction of a metallated Zn site, however, the Cu ligands fail to correctly coordinate the nonnative Zn2+ ion: Trapping of a water molecule causes H48 to change rotamer and swing outwards. The misligation is sterically incompatible with the native structure. As a consequence, SOD1 unfolds locally and interacts with neighboring molecules in the crystal lattice. The findings point to a critical role for the native Zn site in controlling SOD1 misfolding, and show that even subtle changes of the metal-loading sequence can render the wild-type protein the same structural properties as ALS-provoking mutations. This frustrated character of the SOD1 molecule seems to arise from a compromise between optimization of functional and structural features.

Details

Authors
  • Anna Nordlund
  • Lina Leinartaite
  • Saraboji Kadhirvel
  • Christopher Aisenbrey
  • Gerhard Grobner
  • Per Zetterstrom
  • Jens Danielsson
  • Derek Logan
  • Mikael Oliveberg
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Biological Sciences

Keywords

  • functional evolution, protein misfolding, protein disease
Original languageEnglish
Pages (from-to)9667-9672
JournalProceedings of the National Academy of Sciences
Volume106
Issue number24
Publication statusPublished - 2009
Publication categoryResearch
Peer-reviewedYes