The NMR structures of the recombinant cellular form of the prion proteins (PrP C ) of the cat (Felis catus), dog (Canis familiaris), and pig (Sus scrofa), and of two polymorphic forms of the prion protein from sheep (Ovis aries) are presented. In all of these species, PrP C consists of an N-terminal flexibly extended tail with Ϸ100 amino acid residues and a C-terminal globular domain of Ϸ100 residues with three ␣-helices and a short antiparallel ␤-sheet. Although this global architecture coincides with the previously reported murine, Syrian hamster, bovine, and human PrP C structures, there are local differences between the globular domains of the different species. Because the five newly determined PrP C structures originate from species with widely different transmissible spongiform encephalopathy records, the present data indicate previously uncharacterized possible correlations between local features in PrP C threedimensional structures and susceptibility of different mammalian species to transmissible spongiform encephalopathies.mammalian species ͉ feline transmissible spongiform encephalopathy ͉ scrapie T he prion protein (PrP) in mammalian organisms has attracted keen interest because of its relation to a group of invariably fatal neurodegenerative diseases, the transmissible spongiform encephalopathies (TSEs) or ''prion diseases,'' which include bovine spongiform encephalopathy (BSE), CreutzfeldtJakob disease in humans, feline spongiform encephalopathy, and scrapie in sheep. It is well established that expression of the host-encoded PrP is essential for TSE propagation (1, 2). In transgenic mice lacking the gene that encodes PrP, TSEs could not be observed, and the susceptibility toward TSE of these mice could only be restored by reestablishing PrP expression (3). High sequence conservation of PrP in mammalian species (4) indicates that this protein is functionally important in the healthy organism (1, 2), but the search for this unknown function is still ongoing.PrP was identified in the context of TSEs in an aggregated ''scrapie'' isoform of PrP (PrP Sc ) (5), which copurifies with the infective agent (6). This osbservation, the apparent stability of the infectious agent under DNA͞RNA denaturing conditions (7), and the unusual progression of the disease (8) led to the ''protein-only hypothesis.'' This hypothesis proposes that the major component, if not the only one, of the infectious particle causing TSE is a protein, i.e., presumably PrP Sc (1,(7)(8)(9)). An early observation in TSE infections has been the species barrier (10). Compared with transmission with infectious material from the same species, the incubation time for onset of TSEs is prolonged if a given species is challenged with infectious brain homogenate originating from another species. The incubation time may be reduced by consecutive passages within the new host, whereby the adaptation to the new host can take several generations for the disease to show clinical signs (11). In vivo and in vitro experiments indicated that the species ba...

In the otherwise highly conserved NMR structures of cellular prion proteins (PrP C ) from different mammals, species variations in a surface epitope that includes a loop linking a β-strand, β2, with a helix, α2, are associated with NMR manifestations of a dynamic equilibrium between locally different conformations. Here, it is shown that this local dynamic conformational polymorphism in mouse PrP C is eliminated through exchange of Tyr169 by Ala or Gly, but is preserved after exchange of Tyr 169 with Phe. NMR structure determinations of designed variants of mouse PrP(121-231) at 20°C and of wild-type mPrP(121-231) at 37°C together with analysis of exchange effects on NMR signals then resulted in the identification of the two limiting structures involved in this local conformational exchange in wild-type mouse PrP C , and showed that the two exchanging structures present characteristically different solvent-exposed epitopes near the β2-α2 loop. The structural data presented in this paper provided a platform for currently ongoing, rationally designed experiments with transgenic laboratory animals for renewed attempts to unravel the so far elusive physiological function of the cellular prion protein.prion disease | protein structure | protein dynamics | transmissible spongiform encephalopathy T he prion protein (PrP) in its cellular isoform (PrP C ), which is found in healthy mammalian organisms, is among the most extensively studied proteins. Nonetheless, the physiological function of PrP C and its role in the molecular pathways leading to degeneration of the brain in patients suffering from transmissible spongiform encephalopathies still remain elusive (for example, refs. 1-3).The NMR solution structure of the recombinant mouse prion protein (4, 5) has the same molecular architecture as the protein part of PrP C present in healthy organisms (6). It contains a flexibly disordered N-terminal tail of residues 23-124, a globular domain of residues 125-228 with three α-helices and a short twostranded antiparallel β-sheet, and a short C-terminal tail of residues 229-231 (5) [see Schätzl et al. (7) for the numeration of PrPs from different species]. The globular domain in the NMR structures of recombinant PrPs from different mammalian species is highly similar, except for local structure variability in a surface epitope formed in part by a loop of residues 166-172 that connects the strand β2 with the helix α2 (4, 8-16). This polypeptide segment and its immediate spatial environment also show numerous amino acid exchanges among mammals (17-19), which contrasts with the overall high sequence conservation in the globular domain of mammalian PrPs (7). The β2-α2 loop is structurally disordered in the NMR structures of numerous mammalian prion proteins determined at 20°C (4, 9-11), but is well defined in the NMR structures of PrP C from elk, bank vole, horse, wallaby, and rabbit determined under similar conditions (12-16). This structural disorder is associated with the absence of resonances from residues 167-171 from the β2...

No abstract

The recent introduction of bank vole (Clethrionomys glareolus) as an additional laboratory animal for research on prion diseases revealed an important difference when compared to the mouse and the Syrian hamster, since bank voles show a high susceptibility to infection by brain homogenates from a wide range of diseased species such as sheep, goats, and humans. In this context, we determined the NMR structure of the C-terminal globular domain of the recombinant bank vole prion protein (bvPrP) [bvPrP(121-231)] at 20 degrees C. bvPrP(121-231) has the same overall architecture as other mammalian PrPs, with three alpha-helices and an antiparallel beta-sheet, but it differs from PrP of the mouse and most other mammalian species in that the loop connecting the second beta-strand and helix alpha2 is precisely defined at 20 degrees C. This is similar to the previously described structures of elk PrP and the designed mouse PrP (mPrP) variant mPrP[S170N,N174T](121-231), whereas Syrian hamster PrP displays a structure that is in-between these limiting cases. Studies with the newly designed variant mPrP[S170N](121-231), which contains the same loop sequence as bvPrP, now also showed that the single-amino-acid substitution S170N in mPrP is sufficient for obtaining a well-defined loop, thus providing the rationale for this local structural feature in bvPrP.

No abstract

Two lines of transgenic mice expressing mouse/elk and mouse/ horse prion protein (PrP) hybrids, which both form a well-structured β2-α2 loop in the NMR structures at 20°C termed rigid-loop cellular prion proteins (RL-PrP C ), presented with accumulation of the aggregated scrapie form of PrP in brain tissue, and the mouse/ elk hybrid has also been shown to develop a spontaneous transmissible spongiform encephalopathy. Independently, there is in vitro evidence for correlations between the amino acid sequence in the β2-α2 loop and the propensity for conformational transitions to disease-related forms of PrP. To further contribute to the structural basis for these observations, this paper presents a detailed characterization of RL-PrP C conformations in solution. A dynamic local conformational polymorphism involving the β2-α2 loop was found to be evolutionarily preserved among all mammalian species, including those species for which the WT PrP forms an RL-PrP C . The interconversion between two ensembles of PrP C conformers that contain, respectively, a 3 10 -helix turn or a type I β-turn structure of the β2-α2 loop, exposes two different surface epitopes, which are analyzed for their possible roles in the still evasive function of PrP C in healthy organisms and/or at the onset of a transmissible spongiform encephalopathy. Creutzfeldt-Jakob disease in humans, scrapie in sheep and goats, bovine spongiform encephalopathy in cattle, and chronic wasting disease (CWD) in elk and deer (1-3). A common feature of these diseases is the conversion of the cellular form of the prion protein (PrP C ) found in healthy organisms into aggregated isoforms (PrP Sc ), which are deposited primarily in the brain of the diseased individuals (1, 4). Despite extensive investigations, the physiological function of PrP C in healthy organisms as well as the mechanistic aspects of its pathophysiological role remain elusive (4-9). Although the PrP Sc form found in diseased tissue has been intensively studied, other approaches underline the importance of PrP C as a potential target for TSE prevention and medical intervention after outbreak of the disease (10-12), with a special focus on rigid-loop cellular prion proteins (RL-PrP C s) (11,(13)(14)(15), which are investigated in this paper.A common PrP C fold for a globular domain formed by the polypeptide segment of residues 125-228 in mouse PrP (mPrP) [see Schätzl et al. (16) for the numeration in different species], with three α-helices and a short two-stranded antiparallel β-sheet, has been observed for the cellular prion proteins of all mammalian species studied so far (17-27). For WT PrP of most species, parts of the backbone amide group NMR signals of residues in a loop between a β-strand, β2, and a helix, α2, are not observable in NMR spectra recorded with aqueous solutions at pH 4.5 and 20°C at a 1 H resonance frequency of 500 MHz (or higher) because of line broadening by conformational exchange; therefore, the β2-α2 loop in these PrP C s is poorly defined in NMR structures determined un...

No abstract

A survey of plasmids for 51 prion protein constructs from bank vole, cat, cattle, chicken, dog, elk, ferret, frog, fugu, horse, human, pig, sheep, turtle, and wallaby, and for 113 mouse prion protein constructs and variants thereof, is presented. This includes information on the biochemistry of the recombinant proteins, in particular on successful and unsuccessful expression attempts. The plasmid library was generated during the past 12 years in the context of NMR structure determination and biophysical characterization of prion proteins in our laboratory. The plasmids are now available for general use, and are distributed free of charge to not‐for‐profit institutions.