title: Polymorphisms at amino acid residues 141 and 154 influence conformational variation in ovine PrP.
abstract: Polymorphisms in ovine PrP at amino acid residues 141 and 154 are associated with susceptibility to ovine prion disease: Leu141Arg154 with classical scrapie and Phe141Arg154 and Leu141His154 with atypical scrapie. Classical scrapie is naturally transmissible between sheep, whereas this may not be the case with atypical scrapie. Critical amino acid residues will determine the range or stability of structural changes within the ovine prion protein or its functional interaction with potential cofactors, during conversion of PrPC to PrPSc in these different forms of scrapie disease. Here we computationally identified that regions of ovine PrP, including those near amino acid residues 141 and 154, displayed more conservation than expected based on local structural environment. Molecular dynamics simulations showed these conserved regions of ovine PrP displayed genotypic differences in conformational repertoire and amino acid side-chain interactions. Significantly, Leu141Arg154 PrP adopted an extended beta sheet arrangement in the N-terminal palindromic region more frequently than the Phe141Arg154 and Leu141His154 variants. We supported these computational observations experimentally using circular dichroism spectroscopy and immunobiochemical studies on ovine recombinant PrP. Collectively, our observations show amino acid residues 141 and 154 influence secondary structure and conformational change in ovine PrP that may correlate with different forms of scrapie.
authors.affiliation: Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 OES, UK.
authors.forename: Sujeong
authors.initials: S
authors.lastname: Yang
authors.affiliation: Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 OES, UK.
authors.forename: Alana M
authors.initials: AM
authors.lastname: Thackray
authors.affiliation: Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 OES, UK.
authors.forename: Lee
authors.initials: L
authors.lastname: Hopkins
authors.affiliation: Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 OES, UK.
authors.forename: Tom P
authors.initials: TP
authors.lastname: Monie
authors.affiliation: Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK.
authors.forename: David F
authors.initials: DF
authors.lastname: Burke
authors.affiliation: Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 OES, UK.
authors.forename: Raymond
authors.initials: R
authors.lastname: Bujdoso
mesh_terms: D000483:Alleles; D000596:Amino Acids / Q000235:genetics; D000818:Animals; D020022:Genetic Predisposition to Disease; D056004:Molecular Dynamics Simulation; D011328:Prions / Q000737:chemistry* / Q000235:genetics*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D012608:Scrapie / Q000235:genetics* / Q000473:pathology; D012756:Sheep
chemical_list: D000596:Amino Acids; D011328:Prions