title: Characterization of prion protein (PrP)-derived peptides that discriminate full-length PrPSc from PrPC.
abstract: On our initial discovery that prion protein (PrP)-derived peptides were capable of capturing the pathogenic prion protein (PrP(Sc)), we have been interested in how these peptides interact with PrP(Sc). After screening peptides from the entire human PrP sequence, we found two peptides (PrP(19-30) and PrP(100-111)) capable of binding full-length PrP(Sc) in plasma, a medium containing a complex mixture of other proteins including a vast excess of the normal prion protein (PrP(C)). The limit of detection for captured PrP(Sc) was calculated to be 8 amol from a approximately 10(5)-fold dilution of 10% (wt/vol) human variant Creutzfeldt-Jakob disease brain homogenate, with >3,800-fold binding specificity to PrP(Sc) over PrP(C). Through extensive analyses, we show that positively charged amino acids play an important, but not exclusive, role in the interaction between the peptides and PrP(Sc). Neither hydrophobic nor polar interactions appear to correlate with binding activity. The peptide-PrP(Sc) interaction was not sequence-specific, but amino acid composition affected binding. Binding occurs through a conformational domain that is only present in PrP(Sc), is species-independent, and is not affected by proteinase K digestion. These and other findings suggest a mechanism by which cationic domains of PrP(C) may play a role in the recruitment of PrP(C) to PrP(Sc).
authors.affiliation: Novartis Vaccines and Diagnostics, Inc., 4560 Horton Street, Emeryville, CA 94608, USA.
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Lau
authors.forename: Alice Y
authors.initials: AY
authors.lastname: Yam
authors.forename: Melissa M D
authors.initials: MM
authors.lastname: Michelitsch
authors.forename: Xuemei
authors.initials: X
authors.lastname: Wang
authors.forename: Carol
authors.initials: C
authors.lastname: Gao
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Goodson
authors.forename: Robert
authors.initials: R
authors.lastname: Shimizu
authors.forename: Gulliver
authors.initials: G
authors.lastname: Timoteo
authors.forename: John
authors.initials: J
authors.lastname: Hall
authors.forename: Angelica
authors.initials: A
authors.lastname: Medina-Selby
authors.forename: Doris
authors.initials: D
authors.lastname: Coit
authors.forename: Colin
authors.initials: C
authors.lastname: McCoin
authors.forename: Bruce
authors.initials: B
authors.lastname: Phelps
authors.forename: Ping
authors.initials: P
authors.lastname: Wu
authors.forename: Celine
authors.initials: C
authors.lastname: Hu
authors.forename: David
authors.initials: D
authors.lastname: Chien
authors.forename: David
authors.initials: D
authors.lastname: Peretz
mesh_terms: D000906:Antibodies / Q000378:metabolism; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D008863:Microspheres; D010446:Peptide Fragments / Q000097:blood / Q000138:chemical synthesis* / Q000276:immunology; D018621:PrPC Proteins / Q000097:blood / Q000138:chemical synthesis* / Q000145:classification / Q000276:immunology; D018620:PrPSc Proteins / Q000097:blood / Q000138:chemical synthesis* / Q000145:classification / Q000276:immunology; D017096:Prion Diseases / Q000175:diagnosis / Q000276:immunology; D011485:Protein Binding
chemical_list: D000906:Antibodies; D007074:Immunoglobulin G; D010446:Peptide Fragments; D018621:PrPC Proteins; D018620:PrPSc Proteins