title: Definable equilibrium states in the folding of human prion protein.
abstract: The role of conformational intermediates in the conversion of prion protein from its normal cellular form (PrP(C)) to the disease-associated "scrapie" form (PrP(Sc)) remains unknown. To look for such intermediates in equilibrium conditions, we have examined the unfolding transitions of PrP(C), primarily using the chemical denaturant guanidine hydrochloride (GuHCl). When the protein conformation is assessed by NMR, there is a gradual shift of NMR signals in the regions between residues 125-146 and 186-196. The denaturant dependence of these shifts shows that in aqueous solution the native and locally unfolded conformations are both significantly populated. Following this shift, there is the major unfolding transition to generate a substantially unfolded population. However, analysis of NMR chemical shift and intensity changes shows that there is persistent structure in the molecule well beyond this major cooperative unfolding transition. Residual structure within this state is extensive and encompasses the majority of the secondary structure elements found in the native state of the protein.
authors.affiliation: MRC Prion Unit and National Prion Clinic, Institute of Neurology and National Hospital for Neurology and Neurosurgery, Queen Square, London, UK. l.l.hosszu@shef.ac.uk
authors.forename: Laszlo L P
authors.initials: LL
authors.lastname: Hosszu
authors.forename: Mark A
authors.initials: MA
authors.lastname: Wells
authors.forename: Graham S
authors.initials: GS
authors.lastname: Jackson
authors.forename: Samantha
authors.initials: S
authors.lastname: Jones
authors.forename: Mark
authors.initials: M
authors.lastname: Batchelor
authors.forename: Anthony R
authors.initials: AR
authors.lastname: Clarke
authors.forename: C Jeremy
authors.initials: CJ
authors.lastname: Craven
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Waltho
authors.forename: John
authors.initials: J
authors.lastname: Collinge
mesh_terms: D004220:Disulfides / Q000737:chemistry; D019791:Guanidine / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D018621:PrPC Proteins / Q000378:metabolism*; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding
chemical_list: D004220:Disulfides; D018621:PrPC Proteins; D019791:Guanidine