title: A Structural and Functional Comparison Between Infectious and Non-Infectious Autocatalytic Recombinant PrP Conformers.
abstract: Infectious prions contain a self-propagating, misfolded conformer of the prion protein termed PrPSc. A critical prediction of the protein-only hypothesis is that autocatalytic PrPSc molecules should be infectious. However, some autocatalytic recombinant PrPSc molecules have low or undetectable levels of specific infectivity in bioassays, and the essential determinants of recombinant prion infectivity remain obscure. To identify structural and functional features specifically associated with infectivity, we compared the properties of two autocatalytic recombinant PrP conformers derived from the same original template, which differ by >105-fold in specific infectivity for wild-type mice. Structurally, hydrogen/deuterium exchange mass spectrometry (DXMS) studies revealed that solvent accessibility profiles of infectious and non-infectious autocatalytic recombinant PrP conformers are remarkably similar throughout their protease-resistant cores, except for two domains encompassing residues 91-115 and 144-163. Raman spectroscopy and immunoprecipitation studies confirm that these domains adopt distinct conformations within infectious versus non-infectious autocatalytic recombinant PrP conformers. Functionally, in vitro prion propagation experiments show that the non-infectious conformer is unable to seed mouse PrPC substrates containing a glycosylphosphatidylinositol (GPI) anchor, including native PrPC. Taken together, these results indicate that having a conformation that can be specifically adopted by post-translationally modified PrPC molecules is an essential determinant of biological infectivity for recombinant prions, and suggest that this ability is associated with discrete features of PrPSc structure.
authors.affiliation: Departments of Biochemistry and Medicine, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America.
authors.forename: Geoffrey P
authors.initials: GP
authors.lastname: Noble
authors.affiliation: Medicine and Biomedical Sciences Graduate Program, University of California at San Diego, La Jolla, California, United States of America.
authors.forename: Daphne W
authors.initials: DW
authors.lastname: Wang
authors.affiliation: Departments of Biochemistry and Medicine, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Walsh
authors.affiliation: Department of Biological Systems Engineering, Virginia Tech, Blacksburg, Virginia, United States of America.
authors.forename: Justin R
authors.initials: JR
authors.lastname: Barone
authors.affiliation: Departments of Biochemistry and Medicine, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America.
authors.forename: Michael B
authors.initials: MB
authors.lastname: Miller
authors.affiliation: Departments of Biochemistry and Medicine, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America.
authors.forename: Koren A
authors.initials: KA
authors.lastname: Nishina
authors.affiliation: Medicine and Biomedical Sciences Graduate Program, University of California at San Diego, La Jolla, California, United States of America.
authors.forename: Sheng
authors.initials: S
authors.lastname: Li
authors.affiliation: Departments of Biochemistry and Medicine, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America.
authors.forename: Surachai
authors.initials: S
authors.lastname: Supattapone
mesh_terms: D000818:Animals; D055162:Biocatalysis; D003141:Communicable Diseases / Q000276:immunology* / Q000378:metabolism*; D004195:Disease Models, Animal; D051379:Mice; D018621:PrPC Proteins / Q000378:metabolism*; D018620:PrPSc Proteins / Q000378:metabolism*; D011328:Prions / Q000378:metabolism*; D011499:Protein Processing, Post-Translational / Q000276:immunology
chemical_list: D018621:PrPC Proteins; D018620:PrPSc Proteins; D011328:Prions