Shao-Man YIN, Man-Sun SY¹, and Po TIEN^*
( Institute of Microbiology, the Chinese Academy of Sciences, Beijing 100080, China;
¹Institute of Pathology, Case Western Reserve University, Cleveland 44106, USA )

Abstract Production of the pathogenic prion isoform PrP^sc-like molecules is thought to be useful for understanding the mysterious mechanism of conformational conversion process of prion diseases and proving the "protein-only" hypothesis. In this report, an engineered PrP^sc-like conformation was produced from a chimera of mammalian bovine prion protein (bPrP) and yeast Ure2p prion-inducing domain (UPrD). Compared with the normal form of bPrP, the engineered recombinant protein, termed bPrP-UPrD, spontaneously aggregated into ordered fibrils under physiological condition, displaying amyloid-like characteristics, such as fibrillar morphology, birefringence upon binding to Congo red and increased fluorescence intensity with Thioflavine T. Limited resistance to protease K digestion and CD spectroscopy experiments suggested that the structure of bPrP-UPrD had been changed, and adopted a new, high content β-sheet conformation during the fibrils formation. Moreover, bPrP-UPrD amyloid fibrils could recruit more soluble forms into the aggregates. Therefore, the engineered molecules could mimic significant behaviors of PrP^sc and will be helpful for further understanding the mechanism of conformational conversion process.

Key words yeast Ure2p prion-inducing domain; PrP^sc-like molecule; conformational conversion

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Received: October 20, 2003 Accepted: December 8, 2003
This work was supported by the grants from China National Frontier Research Program (No. G1999075602) and the National Natural Foundation of China (No. 30270307)
*Corresponding author: Tel/Fax, 86-10-62554247; E-mail, tienpo@sun.im.ac.cn