NR AWLF
AU Novitskaya,V.; Makarava,N.; Bellon,A.; Bocharova,O.V.; Bronstein,I.B.; Williamson,R.A.; Baskakov,I.V.
TI Probing the conformation of the prion protein within a single amyloid fibril using a novel immunoconformational assay
QU International Conference - Prion 2006: Strategies, advances and trends towards protection of society - 3.10.-6.10.2006, Torino, Italy, Lingotto Conference Centre - Oral sessions ORAL-14
PT Konferenz-Vortrag
AB The coexistence of multiple strains or subtypes of the disease-related isoform of PrP in natural isolates, together with the observed conformational heterogeneity of PrP amyloid fibrils generated in vitro, indicates the importance of probing conformation of single particles within heterogeneous samples. Using an array of PrP-specific antibodies, we report the development of a novel immunoconformational assay. Uniquely, application of this new technology allows the conformation of multimeric PrP within a single fibril or particle to be probed without pretreatment of the sample with proteinase K. Using amyloid fibrils prepared from full-length recombinant PrP, we demonstrated the utility of this assay to define (i) PrP regions that are surface-exposed or buried, (ii) the susceptibility of defined PrP regions to GdnHCl-induced denaturation, and (iii) the conformational heterogeneity of PrP fibrils as measured for either the entire fibrillar population or for individual fibrils. Specifically, PrP regions 159-174 and 224-230 were shown to be buried, and were the most resistant to denaturation. The 132-156 segment of PrP was found to be cryptic under native conditions and solvent-exposed under partially denaturing conditions, whereas the region 95-105 was solvent-accessible regardless Sc of the solvent conditions. Remarkably, a subfraction of fibrils showed immunoreactivity to PrP specific antibodies designated as IgGs 89-112 and 136-158. The immunoreactivity of the conformational epitopes was reduced upon exposure to partially denaturing conditions. Unexpectedly, PrPsc-specific antibodies revealed conformational polymorphisms even within individual fibrils. Our studies provide valuable new insight into fibrillar substructure and offer a new tool for probing the conformation of single PrP fibrils.
AD V. Novitskaya, N. Makareva, O.V. Bocharova: Medical Biotechnology Center, University of Maryland Biotechnology Institute, Baltimore, MD 21201, USA; I.V. Baskakov: Medical Biotechnology Center, University of Maryland Biotechnology Institute, Baltimore, MD 21201, USA and Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, MD 21201, USA; A. Bellon, R.A. Williamson: Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037, USA; I.B. Bronstein: Institute for Animal Health, Compton Laboratories, Compton, RG20 7NN, UK
SP englisch
PO Italien