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|1m25, 20 NMR models ()|
STRUCTURE OF SYNTHETIC 26-MER PEPTIDE CONTAINING 145-169 SHEEP PRION PROTEIN SEGMENT AND C-TERMINAL CYSTEINE IN TFE SOLUTION
The conformational conversion of the nonpathogenic "cellular" prion isoform into a pathogenic "scrapie" protease-resistant isoform is a fundamental event in the onset of transmissible spongiform encephalopathies (TSE). During this pathogenic conversion, helix H1 and its two flanking loops of the normal prion protein are thought to undergo a conformational transition into a beta-like structure. A peptide spanning helix H1 and beta-strand S2 (residues 142-166 in human numbering) was studied by circular dichroism and nuclear magnetic resonance spectroscopies. This peptide in aqueous solution, in contrast to many prion fragments studied earlier (1) is highly soluble and (2) does not aggregate until the millimolar concentration range, and (3) exhibits an intrinsic propensity to a beta-hairpin-like conformation at neutral pH. We found that this peptide can also fold into a helix H1 conformation when dissolved in a TFE/PB mixture. The structures of the peptide calculated by MD showed solvent-dependent internal stabilizing forces of the structures and evidenced a higher mobility of the residues following the end of helix H1. These data suggest that the molecular rearrangement of this peptide in region 152-156, particularly in position 155, could be associated with the pathogenic conversion of the prion protein.
Possible role of region 152-156 in the structural duality of a peptide fragment from sheep prion protein., Megy S, Bertho G, Kozin SA, Debey P, Hoa GH, Girault JP, Protein Sci. 2004 Dec;13(12):3151-60. Epub 2004 Nov 10. PMID:15537751
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
[PRIO_SHEEP] Note=Polymorphism at position 171 may be related to the alleles of scrapie incubation-control (SIC) gene in this species. Note=Found in high quantity in the brain of humans and animals infected with degenerative neurological diseases such as kuru, Creutzfeldt-Jakob disease (CJD), Gerstmann-Straussler syndrome (GSS), scrapie, bovine spongiform encephalopathy (BSE), transmissible mink encephalopathy (TME), etc. Note=Scrapie is a transmissible neurodegenerative disorder of sheep and goats. Most sheep that contract the disease naturally die between 24 and 50 months of age. The incubation period in sheep depends on the strain(s) of the infecting pathogen, sheep age at exposure, and the sheep genotype. The survival time is mainly determined by a single genetic locus, SIP, which has two alleles, susceptible (sa) and resistant (pa). Short incubation period is conferred by the partially dominant sa allele. Scrapie can be spread between flockmates, or it can be transmitted from an infected ewe to its lamb.
[PRIO_SHEEP] May play a role in neuronal development and synaptic plasticity. May be required for neuronal myelin sheath maintenance. May play a role in iron uptake and iron homeostasis. Soluble oligomers are toxic to cultured neuroblastoma cells and induce apoptosis (in vitro). Association with GPC1 (via its heparan sulfate chains) targets PRNP to lipid rafts. Also provides Cu(2+) or ZN(2+) for the ascorbate-mediated GPC1 deaminase degradation of its heparan sulfate side chains (By similarity).
About this Structure
1m25 is a 1 chain structure. Full experimental information is available from OCA.