Photo-activity induced by amyloidogenesis.
Accumulation of chemically altered proteins is a noted characteristic of biological aging, and increasing evidence suggests a variety of deleterious cellular developments associated with senescence. Concomitantly, the "aging" of protein deposits associated with numerous neurological disorders may involve covalent modifications of their constituents. However, the link between disease-related protein aggregation and chemical alterations of its molecular constituents has yet to be established. The present study of amyloidogenic alpha-synuclein protein points to a decisive change in the biophysical behavior of growing protein aggregates with progressive photo-activity in the visible range of the electromagnetic spectrum. I hypothesize that the photo-activity induced by filament formation is governed by the same mechanism as seen for the intrinsic chromophore of 4-(p-hydroxybenzylidene)-5-imidazolinone-type in the family of green fluorescent proteins. This type of the covalent alterations is initiated concurrently with amyloid elongation and involves a complex multi-step process of chain cyclization, amino acid dehydration, and aerial oxidation. Given that different stages in filament formation yield distinct optical characteristics, the photo-activity induced by amyloidogenesis may have application in molecular biology by enabling in vivo visualization of protein aggregation and its impact on cellular function.
Tcherkasskaya
Olga
O
Department of Biochemistry and Molecular Biology, Georgetown University School of Medicine, Washington, DC 20057, USA. ovt@georgetown.edu
D000682:Amyloid / Q000096:biosynthesis*; D006801:Humans; D046529:Microscopy, Electron, Transmission; D013050:Spectrometry, Fluorescence; D051844:alpha-Synuclein / Q000737:chemistry* / Q000235:genetics / Q000648:ultrastructure
D000682:Amyloid; D051844:alpha-Synuclein