Fiber diffraction of synthetic a-synuclein filaments shows amyloid-like cross-ß conformation

Filamentous inclusions made of a-synuclein constitute the defining neuropathological characteristic of Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. Rare familial cases of Parkinson's disease are associated with mutations A53T and A30P in a-synuclein. We report here the assembly properties and secondary structure characteristics of recombinant a-synuclein. Carboxy-terminally truncated human a-synuclein (1-87) and (1-120) showed the fastest rates of assembly, followed by human A53T a-synuclein, and rat and zebra finch a-synuclein. Wild-type human a- synuclein and the A30P mutant showed slower rates of assembly. Upon shaking, filaments formed within 48 h at 37°C. The related proteins ß- and ¿- synuclein only assembled after several weeks of incubation. Synthetic human a-synuclein filaments were decorated by an antibody directed against the carboxy-terminal 10 amino acids of a-synuclein, as were filaments extracted from dementia with Lewy bodies and multiple system atrophy brains. Circular dichroism spectroscopy indicated that a-synuclein undergoes a conformational change from random coil to ß-sheet structure during assembly. X-ray diffraction and electron diffraction of the a-synuclein assemblies showed a cross-ß conformation characteristic of amyloid

Synuclein Proteins of the Pufferfish Fugu rubripes: Sequences and Functional Characterization

In humans, three genes encode the related a-, ß-, and ¿-synucleins, which function as lipid-binding proteins in vitro. They are being widely studied, mainly because of the central involvement of a-synuclein in a number of neurodegenerative diseases, including Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. In these diseases, the normally soluble a-synuclein assembles into abnormal filaments. Here, we have identified and characterized the synuclein gene family from the pufferfish Fugu rubripes. It consists of four genes, which encode a-, ß-, ¿1-, and ¿2-synucleins. They range from 113 to 127 amino acids in length and share many of the characteristics of human synucleins, including the presence of imperfect amino-terminal repeats of 11 amino acids, a hydrophobic middle region, and a negatively charged carboxy-terminus. All four synucleins are expressed in the Fugu brain. Recombinant Fugu synucleins exhibited differential liposome binding, which was strongest for a-synuclein, followed by ß-, ¿2-, and ¿1-synucleins. In assembly experiments, Fugu a-, ¿1-, and ¿2-synucleins formed filaments more readily than human a-synuclein. Fugu ß-synuclein, by contrast, failed to assemble in bulk. Filament assembly of synucleins was directly proportional to their degree of hydrophobicity and their tendency to form ß-sheet structure, and correlated inversely with their net charge

Synuclein Proteins of the Pufferfish <i>Fugu rubripes</i>: Sequences and Functional Characterization^†

In humans, three genes encode the related α-, β-, and γ-synucleins, which function as lipid-binding proteins in vitro. They are being widely studied, mainly because of the central involvement of α-synuclein in a number of neurodegenerative diseases, including Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. In these diseases, the normally soluble α-synuclein assembles into abnormal filaments. Here, we have identified and characterized the synuclein gene family from the pufferfish Fugu rubripes. It consists of four genes, which encode α-, β-, γ1-, and γ2-synucleins. They range from 113 to 127 amino acids in length and share many of the characteristics of human synucleins, including the presence of imperfect amino-terminal repeats of 11 amino acids, a hydrophobic middle region, and a negatively charged carboxy-terminus. All four synucleins are expressed in the Fugu brain. Recombinant Fugu synucleins exhibited differential liposome binding, which was strongest for α-synuclein, followed by β-, γ2-, and γ1-synucleins. In assembly experiments, Fugu α-, γ1-, and γ2-synucleins formed filaments more readily than human α-synuclein. Fugu β-synuclein, by contrast, failed to assemble in bulk. Filament assembly of synucleins was directly proportional to their degree of hydrophobicity and their tendency to form β-sheet structure, and correlated inversely with their net charge