Fig. 6. Suramin analogues induce aggregation of purified recombinant mouse prion protein. (A,B) Recombinant mouse PrP (amino acids 23-231) (50 ng/µl) was incubated overnight with 10 or 100 µg/ml of the suramin analogues indicated in sodium acetate buffer at pH 7. Samples were then subjected to ultracentrifugation in the presence of 1% sarcosyl. Pellets and supernatants were run on SDS-PAGE and analysed by immunoblotting using the mouse monoclonal antibody 4H11. Mock-treated recombinant PrP was detected in the soluble as well as in the insoluble fractions. Upon treatment with NF023, NF449, NF078, NF110, NF305, NF068 and suramin, a clear shift into pellet fractions was detected whereas ANTS (B, lanes 5-8) and NF043 (B, lanes 13-16) did not affect the solubility of PrP.