tailieunhanh - Báo cáo khoa học: Copper is required for prion protein-associated superoxide dismutase-l activity in Pichia pastoris

The prion protein (PrP) is the key protein implicated in transmissible spongiform encephalopathies. It is a metalloprotein that binds manganese and copper. The latter is involved in the physiological function of the pro-tein. We have previously found that PrP expression inPichia pastorisaffects intracellular metal ion concentrations and that formation of protease-resistant PrP is induced by additional copper and⁄or manganese. | ễFEBS Journal Copper is required for prion protein-associated superoxide dismutase-l activity in Pichia pastoris Carina Treiber1 Rudiger Pipkorn2 Christoph Weise1 Gudrun Holland3 and Gerd Multhaup1 1 Freie Universitaet Berlin Institut fuer Chemie und Biochemie Germany 2 DKFZ-German Cancer Research Center Heidelberg Germany 3 Robert Koch Institut Abteilung fuer Infektionskrankheiten Berlin Germany Keywords copper glycosylation Pichia pastoris prion protein superoxide dismutase Correspondence G. Multhaup Institut fuer Chemie und Biochemie Freie Universitaet Berlin Thielallee 63 D-14195 Berlin Germany Fax 49 30 838 565 09 Tel 49 30 838 555 33 E-mail multhaup@ Received 7 November 2006 revised 22 December 2006 accepted 3 January 2007 doi The prion protein PrP is the key protein implicated in transmissible spongiform encephalopathies. It is a metalloprotein that binds manganese and copper. The latter is involved in the physiological function of the protein. We have previously found that PrP expression in Pichia pastoris affects intracellular metal ion concentrations and that formation of proteaseresistant PrP is induced by additional copper and or manganese. In this study we show that heterologously expressed PrP is post-translationally modified and transported to the cell wall. We found by combining three different test systems that PrP itself had gained superoxide dismutase-like activity in P. pastoris. However this activity could not be inhibited by KCN and depended on additional copper in the medium. Thus this study defines the conditions under which PrP exhibits superoxide dismutase-like activity by showing that copper must be present for the protein to participate in scavenging and detoxification of reactive oxygen species. Transmissible spongiform encephalopathies are fatal neurodegenerative diseases occurring in humans and animals in infectious sporadic and genetic forms. After prion infection cellular prion .