title: Role of advanced glycation on aggregation and DNA binding properties of α-synuclein.
abstract: Parkinson's disease (PD) is a neurodegenerative disease with multiple etiologies. Advanced glycation end products (AGEs) accumulate in the aging brain and could be one of the reasons for age-related diseases like PD. Oxidative stress also leads to the formation of AGEs and may be involved in neurodegeneration by altering the properties of proteins. α-Synuclein is involved in pathogenesis of PD and there are limited studies on the role of AGE-α-synuclein in neurodegeneration. We studied the aggregation and DNA binding ability of AGE-α-synuclein in vitro. α-Synuclein is glycated using methylglyoxal and formation of AGE-α-synuclein is characterized using fluorescence studies, intrinsic tyrosine fluorescence, and fructosamine estimation. The results indicated that AGE-α-synuclein aggregates into smaller globular-like aggregates compared to fibrils formed with native α-synuclein. Further, it is found that AGE-α-synuclein induced conformational changes in scDNA from B-form to B-C-A mixed conformation. Additionally, AGE-α-synuclein altered DNA integrity as evidenced by the melting temperature, ethidium bromide, and DNAse I sensitivity studies. AGE-α-synuclein converted biphasic Tm to higher monophasic Tm. The Tm of AGE-α-synuclein-scDNA complex is more than that of native α-synuclein-scDNA complex, indicating that AGE-α-synuclein stabilized the uncoiled scDNA. AGE-α-synuclein could stabilize the uncoiled scDNA, as shown by the decrease in the number of ethidium bromide binding molecules per base pair of DNA. DNAse I sensitive studies indicated that both AGE-α-synuclein-scDNA and α-synuclein-scDNA are resistant to DNAse I digestion. The relevance of these findings to neuronal cell death is discussed.
authors: Department of Biochemistry and Nutrition, Central Food Technological Research Institute, CSIR Unit, Mysore, India.
authors: Vasudevaraju
authors: V
authors: Padmaraju
authors: Jamuna J
authors: JJ
authors: Bhaskar
authors: Ummiti J S
authors: UJ
authors: Prasada Rao
authors: Paramahans V
authors: PV
authors: Salimath
authors: K S
authors: KS
authors: Rao
mesh_terms: D000818:Animals; D004247:DNA / Q000378:metabolism* / Q000648:ultrastructure; D017127:Glycation End Products, Advanced / Q000378:metabolism*; D006031:Glycosylation / Q000187:drug effects; D006801:Humans; D046529:Microscopy, Electron, Transmission; D011485:Protein Binding / Q000187:drug effects / Q000502:physiology; D013997:Time Factors; D051844:alpha-Synuclein / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D017127:Glycation End Products, Advanced; D051844:alpha-Synuclein; D004247:DNA