sod1 and amyotrophic lateral sclerosis mutations and oligomerizationsod1突变和肌萎缩性脊髓侧索硬化症和寡聚化.pdfVIP

SOD1 and Amyotrophic Lateral Sclerosis: Mutations and Oligomerization 1,2 1 1 1 1 Lucia Banci , Ivano Bertini *, Mirela Boca , Stefania Girotto , Manuele Martinelli , Joan Selverstone Valentine3, Miguela Vieru1 1 Magnetic Resonance Center (CERM), Department of Chemistry, University of Florence, Florence, Italy, 2 FiorGen Foundation, Florence, Italy, 3 Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California, United States of America Abstract There are about 100 single point mutations of copper, zinc superoxide dismutase 1 (SOD1) which are reported (http://alsod.iop. kcl.ac.uk/Als/index.aspx) to be related to the familial form (fALS) of amyotrophic lateral sclerosis (ALS). These mutations are spread all over the protein. It is well documented that fALS produces protein aggregates in the motor neurons of fALS patients, which have been found to be associated to mitochondria. We selected eleven SOD1 mutants, most of them reported as pathological, and characterized them investigating their propensity to aggregation using different techniques, from circular dichroism spectra to ThT-binding fluorescence, size-exclusion chromatography and light scattering spectroscopy. We show here that these eleven SOD1 mutants, only when they are in the metal-free form, undergo the same general mechanism of oligomerization as found for the WT metal-free protein. The rates of oligomerization are different but eventually they give rise to the same type of soluble oligomeric species. These oligomers are formed through oxidation of the two free cysteines of SOD1 (6 and 111) and stabilized by hydrogen bonds, between beta strands, thus forming amyloid-like structures. SOD1 enters the mitochondria as demetallated and