Journal Article

The Structural Architecture of an Infectious Mammalian Prion Using Electron Cryomicroscopy

Fernández, José Jesús, Afanasyev, Pavel, Requena, Jesús R., Rosa, Isaac, Cebey, Lino, Ramos, Adriana, Vos, Matthijn R., Vidal, Enric, Peters, Peter J., Young, Howard S., Wille, Holger, Sevillano, Alejandro M., Vázquez-Fernández, Ester, van Heel, Marin, Renault, Ludovic

2016

Overview

The structure of the infectious prion protein (PrPSc), which is responsible for Creutzfeldt-Jakob disease in humans and bovine spongiform encephalopathy, has escaped all attempts at elucidation due to its insolubility and propensity to aggregate. PrPSc replicates by converting the non-infectious, cellular prion protein (PrPC) into the misfolded, infectious conformer through an unknown mechanism. PrPSc and its N-terminally truncated variant, PrP 27-30, aggregate into amorphous aggregates, 2D crystals, and amyloid fibrils. The structure of these infectious conformers is essential to understanding prion replication and the development of structure-based therapeutic interventions. Here we used the repetitive organization inherent to GPI-anchorless PrP 27-30 amyloid fibrils to analyze their structure via electron cryomicroscopy. Fourier-transform analyses of averaged fibril segments indicate a repeating unit of 19.1 Å. 3D reconstructions of these fibrils revealed two distinct protofilaments, and, together with a molecular volume of 18,990 Å3, predicted the height of each PrP 27-30 molecule as ~17.7 Å. Together, the data indicate a four-rung β-solenoid structure as a key feature for the architecture of infectious mammalian prions. Furthermore, they allow to formulate a molecular mechanism for the replication of prions. Knowledge of the prion structure will provide important insights into the self-propagation mechanisms of protein misfolding.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Aggregates / Amyloid - genetics / Amyloid - ultrastructure / Animals / Biology / Biology and Life Sciences / Biomedical research / Bovine spongiform encephalopathy / Cattle / Colleges & universities / Creutzfeldt-Jakob disease / Creutzfeldt-Jakob Syndrome - genetics / Creutzfeldt-Jakob Syndrome - metabolism / Creutzfeldt-Jakob Syndrome - pathology / Cryoelectron Microscopy / Crystals / Encephalopathy, Bovine Spongiform - genetics / Encephalopathy, Bovine Spongiform - metabolism / Encephalopathy, Bovine Spongiform - pathology / Funding / Humans / Laboratories / Mammals / Medicine and Health Sciences / Physical Sciences / Physiological aspects / Prions / Protein folding / PrPC Proteins - genetics / PrPC Proteins - ultrastructure / PrPSc Proteins - genetics / PrPSc Proteins - ultrastructure / Research and Analysis Methods / Structure