Structural effects of stabilization and complexation of a zinc-deficient superoxide dismutase

Heliyon

Rosanna Squitti¹  Stefano L. Sensi²  Tania M. Manieri³  Giselle Cerchiaro⁴ 

[1] Departments of Neurology and Pharmacology, Institute for Mind Impairments and Neurological Disorders – iMIND, University of California - Irvine, USA;Center for Advanced Studies and Technology - CAST, University G. d'Annunzio of Chieti-Pescara, Italy;Center for Natural Sciences and Humanities, Federal University of ABC - UFABC, Avenida dos Estados 5001, Bloco B, 09210-580, Santo André, SP, Brazil;IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy;

关键词: Superoxide dismutase;    SOD1;    Alzheimer's disease;    Circular dichroism;    Zinc;    Copper;   

DOI  :  

来源: DOAJ

【 摘 要 】

The activity of the erythrocyte Cu2,Zn2-superoxide dismutase (SOD1) is altered in Alzheimer's disease (AD) patients. These patients, compared to healthy subjects, exhibit low plasmatic zinc (Zn) levels in the presence of high plasmatic levels of copper (Cu). SOD1 is an antioxidant enzyme characterized by the presence of two metal ions, Cu and Zn, on its active site. On the SOD1, Cu exerts a catalytic role, and Zn serves a structural function. In this study, we generated a modified SOD1 characterized by an altered capacity to complex Zn. The study investigates the metal-binding dynamics of the enzyme, estimating the stability of a SOD1 protein lacking the appropriate Zn site complexation. Our mutant SOD1 possesses a double amino acid mutation (T135S and K136E) that interferes with the correct Zn site complexation. We found that the protein mutations produce unstable Zn coordination and lower enzymatic activity even when complexed with Cu. Analysis with circular dichroism (CD) spectra on metal titration showed a considerable difference between the two Zn entries in the native dimeric enzyme, and Cu presents a simultaneous entrance in the protein. Otherwise, the mutant T135S,K136E-SOD1 exhibited Zn and Cu complexation instability, being a useful in vitro model to study the SOD1 behavior in AD patients.

【 授权许可】

Unknown