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The elongation of yeast prion fibers involves separable steps of association and conversion

Title data

Scheibel, Thomas ; Bloom, Jesse ; Lindquist, Susan L.:
The elongation of yeast prion fibers involves separable steps of association and conversion.
In: Proceedings of the National Academy of Sciences of the United States of America. Vol. 101 (2004) Issue 8 . - pp. 2287-2292.
ISSN 1091-6490

Official URL: Volltext

Abstract in another language

A self-perpetuating change in the conformation of the translation termination factor Sup35p is the basis for the prion [PSI +], a protein-based genetic element of Saccharomyces cerevisiae. In a process closely allied to in vivo conversion, the purified soluble, prion-determining region of Sup35p (NM) converts to amyloid fibers by means of nucleated conformational conversion. First, oligomeric species convert to nuclei, and these nuclei then promote polymerization of soluble protein into amyloid fibers. To elucidate the nature of the polymerization step, we created single-cysteine substitution mutants at different positions in NM to provide unique attachment sites for various probes. In vivo, the mutants behaved like wild-type protein in both the [psi –] and [PSI +] states. In vitro, they assembled with wild-type kinetics and formed fibers with the same morphologies. When labeled with fluorescent probes, two mutants, NMT158C and NME167C, exhibited a change in fluorescence coincident with amyloid assembly. These mutants provided a sensitive measure for the kinetics of fiber elongation, and the lag phase in conversion. The cysteine in the mutant NMK184C remained exposed after assembly. When labeled with biotin and bound to streptavidin beads, it was used to capture radiolabeled soluble NM in the process of conversion. This process established the existence of a detergent-susceptible intermediate in fiber elongation. Thus, the second stage of nucleated conformational conversion, fiber elongation, itself contains at least two steps: the association of soluble protein with preformed fibers to form an assembly intermediate, followed by conformational conversion into amyloid.

Further data

Item Type: Article in a journal
Refereed: Yes
Institutions of the University: Faculties
Faculties > Faculty of Engineering Science
Faculties > Faculty of Engineering Science > Chair Biomaterials
Faculties > Faculty of Engineering Science > Chair Biomaterials > Chair Biomaterials - Univ.-Prof. Dr. Thomas Scheibel
Profile Fields > Advanced Fields > Advanced Materials
Profile Fields > Advanced Fields > Molecular Biosciences
Profile Fields > Advanced Fields > Polymer and Colloid Science
Profile Fields > Emerging Fields > Food and Health Sciences
Profile Fields
Profile Fields > Advanced Fields
Profile Fields > Emerging Fields
Result of work at the UBT: No
DDC Subjects: 600 Technology, medicine, applied sciences > 620 Engineering
Date Deposited: 16 Mar 2015 13:17
Last Modified: 05 Sep 2022 07:35