NR ABCE
AU Baxa,U.; Speransky,V.; Steven,A.C.; Wickner,R.B.
TI Mechanism of inactivation on prion conversion of the Saccharomyces cerevisiae Ure2 protein
QU Proceedings of the National Academy of Sciences of the United States of America 2002 Apr 16; 99(8): 5253-60
IA http://www.pnas.org/cgi/content/full/99/8/5253
PT journal article
AB The [URE3] infectious protein (prion) of Saccharomyces cerevisiae is a self-propagating amyloid form of Ure2p. The C-terminal domain of Ure2p controls nitrogen catabolism by complexing with the transcription factor, Gln3p, whereas the asparagine-rich N-terminal "prion" domain is responsible for amyloid filament formation (prion conversion). On filament formation, Ure2p is inactivated, reflecting either a structural change in the C-terminal domain or steric blocking of its interaction with Gln3p. We fused the prion domain with four proteins whose activities should not be sterically impeded by aggregation because their substrates are very small: barnase, carbonic anhydrase, glutathione S-transferase, and green fluorescent protein. All formed amyloid filaments in vitro, whose diameters increased with the mass of the appended enzyme. The helical repeat lengths were consistent within a single filament but varied with the construct and between filaments from a single construct. CD data suggest that, in the soluble fusion proteins, the prion domain has no regular secondary structure, whereas earlier data showed that in filaments, it is virtually all beta-sheet. In filaments, the activity of the appended proteins was at most mildly reduced, when substrate diffusion effects were taken into account, indicating that they retained their native structures. These observations suggest that the amyloid content of these filaments is confined to their prion domain-containing backbones and imply that Ure2p is inactivated in [URE3] cells by a steric blocking mechanism.
MH Amyloid/chemistry; Circular Dichroism; Escherichia coli/metabolism; Microscopy, Electron; Plasmids/metabolism; Prions/*metabolism; Protein Binding; Protein Conformation; Protein Structure, Secondary; Protein Structure, Tertiary; Recombinant Fusion Proteins/metabolism; Research Support, Non-U.S. Gov't; Saccharomyces cerevisiae/*metabolism; Saccharomyces cerevisiae Proteins/*chemistry; Spectrometry, Fluorescence
AD Laboratory of Structural Biology, National Institute of Arthritis, Musculoskeletal, and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
SP englisch
PO USA
OR Prion-Krankheiten 1