NR ADOZ
AU Dos Reis,S.; Coulary-Salin,B.; Forge,V.; Lascu,I.; Begueret,J.; Saupe,S.J.
TI The HET-s prion protein of the filamentous fungus Podospora anserina aggregates in vitro into amyloid-like fibrils
QU The Journal of Biological Chemistry 2002 Feb 22; 277(8): 5703-6
PT journal article
AB The HET-s protein of Podospora anserina is a fungal prion. This protein behaves as an infectious cytoplasmic element that is transmitted horizontally from one strain to another. Under the prion form, the HET-s protein forms aggregates in vivo. The specificity of this prion model compared with the yeast prions resides in the fact that under the prion form HET-s causes a growth inhibition and cell death reaction when co-expressed with the HET-S protein from which it differs by 13 residues. Herein we describe the purification and initial characterization of recombinant HET-s protein expressed in Escherichia coli. The HET-s protein self-associates over time into high molecular weight aggregates. These aggregates greatly accelerate precipitation of the soluble form. HET-s aggregates appear as amyloid-like fibrils using electron microscopy. They bind Congo Red and show birefringence under polarized light. In the aggregated form, a HET-s fragment of approximately 7 kDa is resistant to proteinase K digestion. CD and FTIR analyses indicate that upon transition to the aggregated state, the HET-s protein undergoes a structural rearrangement characterized by an increase in antiparallel beta-sheet structure content. These results suggest that the [Het-s] prion element propagates in vivo as an infectious amyloid.
MH Amyloid/*chemistry; Cloning, Molecular; Comparative Study; Escherichia coli/genetics; Fungal Proteins/*chemistry/isolation & purification/ultrastructure; Microscopy, Electron; Models, Molecular; Molecular Weight; Prions/*chemistry; Protein Conformation; Protein Denaturation; Protein Renaturation; Saccharomyces cerevisiae/physiology; Sordariales/*chemistry; Spectrophotometry, Infrared; Support, Non-U.S. Gov't
AD les Laboratoires Genetique Moleculaire des Champignons, Institut de Biochimie et de Genetique Cellulaires, UMR 5095 CNRS/Universite de Bordeaux 2, 33077 Bordeaux cedex, France.
SP englisch
PO USA