NR AOTD
AU Gill,A.C.; Ritchie,M.A.; Hope,J.; Blanch,E.W.; Hecht,L.; Barron,L.D.
TI Structure and Function of the N-terminus of PrP
QU International Conference - Prion diseases: from basic research to intervention concepts - TSE-Forum, 08.10.-10.10.2003, Gasteig, München - Poster session - BR-103
PT Konferenz-Poster
AB
Analysing 'unstructured' regions of proteins can be problematic, a fact that has limited the amount of secondary structural data on the N-terminal region of PrP. In addition, transgenic mice expressing PrP with certain N-terminal truncations develop normally and are susceptible to infection with TSE disease; it has therefore been assumed that this region of the protein is not directly involved in the conversion of PrPc to PrPsc. The N-terminal region, however, appears to account for many of the functions proposed for PrPc and is implicated in receptor-mediated endocytosis and stabilisation of the structured C-terminal domain. It is vital that we have more information on the various structures that this 'disordered tail' may adopt to delineate its role in the function and mal-function of PrP.
Our discovery of proline 4-hydroxylation towards the N-terminus of PrP implies that poly proline II (PPII) helix structure is formed in this region. Using synthetic peptides, in addition to full length and truncated prion proteins, we have applied various forms of spectroscopy to investigate structural and functional aspects of PrP and to evaluate the extent of PPII formation. We have demonstrated conclusively that PPII does form in the N-terminus of full length PrP and find PPII structure in various regions of the N-terminus, not just around the site of hydroxylation. We also find corresponding PPII structure in the N-terminal region of avian PrP, which has a rather different sequence to the mammalian N-terminus. We find that both avian and mammalian forms share remarkably similar copper ion binding properties and that copper binding causes a shift in secondary structure away from PPII helix. Thus, PPII formation in the N-terminal region may facilitate copper binding and play an important role in regulating the function of PrP and its interaction with other molecules.
AD Andrew C. Gill, Mark A. Ritchie, James Hope, Institute for Animal Health, Compton, UK; Ewan W. Blanch, Lutz Hecht, Laurence D. Barron, University of Glasgow, Glasgow, UK
SP englisch
PO Deutschland