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.
Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0830, USA.
Eric D
ED
Ross
Ulrich
U
Baxa
Reed B
RB
Wickner
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