Scrambled prion domains form prions and amyloid.
The [URE3] prion of Saccharomyces cerevisiae is a self-propagating amyloid form of Ure2p. The amino-terminal prion domain of Ure2p is necessary and sufficient for prion formation and has a high glutamine (Q) and asparagine (N) content. Such Q/N-rich domains are found in two other yeast prion proteins, Sup35p and Rnq1p, although none of the many other yeast Q/N-rich domain proteins have yet been found to be prions. To examine the role of amino acid sequence composition in prion formation, we used Ure2p as a model system and generated five Ure2p variants in which the order of the amino acids in the prion domain was randomly shuffled while keeping the amino acid composition and C-terminal domain unchanged. Surprisingly, all five formed prions in vivo, with a range of frequencies and stabilities, and the prion domains of all five readily formed amyloid fibers in vitro. Although it is unclear whether other amyloid-forming proteins would be equally resistant to scrambling, this result demonstrates that [URE3] formation is driven primarily by amino acid composition, largely independent of primary sequence.
Ross
Eric D
ED
Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0830, USA.
Baxa
Ulrich
U
Wickner
Reed B
RB
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry; D000682:Amyloid / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D005979:Glutathione Peroxidase; D006801:Humans; D008969:Molecular Sequence Data; D011328:Prions / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011897:Random Allocation; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D016415:Sequence Alignment
D000596:Amino Acids; D000682:Amyloid; D011328:Prions; D029701:Saccharomyces cerevisiae Proteins; D005979:Glutathione Peroxidase; C067020:URE2 protein, S cerevisiae