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	EMBO Rep. Dec (2007); 8(12):1196-201
Alternative assembly pathways of the amyloidogenic yeast prion determinant Sup35-NM-
Hess S, Lindquist SL, Scheibel T
Department Chemie, Technische Universitat Munchen, Lichtenbergstrasse 4, Garching 85747, Germany-
Abstract: The self-perpetuating conformational change of the translation termination factor Sup35 is associated with a prion phenomenon of Saccharomyces cerevisiae- In vitro, the prion-determining region -NM- of Sup35 assembles into amyloid-like fibres through a mechanism of nucleated conformational conversion- Here, we describe an alternative assembly pathway of NM that produces filaments that are composed of beta-strands and random coiled regions with several-fold smaller diameters than the amyloid fibres- NM filaments are not detectable with either thioflavin T or Congo Red and do not show SDS or protease resistance- As filaments do not self-convert into fibres and do not act as seed, they are not intermediates of amyloid fibre formation- Instead, they represent a stable off-pathway form- Similar to mammalian prion proteins, Sup35 contains oligopeptide repeats located in the NM region- We found that the number of repeats determines the partitioning of the protein between filaments and amyloid-like fibres- Low numbers of repeats favour the formation of the filamentous structure, whereas high numbers of repeats favour the formation of amyloid-like fibres-
[PUBMED: 17975557]