TAILIEUCHUNG - Báo cáo khoa học: Channel-forming activities of peroxisomal membrane proteins from the yeast Saccharomyces cerevisiae

Highly-purified peroxisomes from the yeastSaccharomyces cerevisiaegrown on oleic acid were investigated for the presence of channel (pore)-forming proteins in the membrane of these organelles. Solubilized membrane pro-teins were reconstituted in planar lipid bilayers and their pore-forming activity was studied by means of multiple-channel monitoring or single-channel analysis. | ễFEBS Journal Channel-forming activities of peroxisomal membrane proteins from the yeast Saccharomyces cerevisiae Silke Grunau1 2 z Sabrina Mindthoff1 Hanspeter Rottensteiner1 Raija T. Sormunen3 J. Kalervo Hiltunen2 Ralf Erdmann1 and Vasily D. Antonenkov2 1 Institut fur Physiologische Chemie Abt. Systembiochemie Bochum Germany 2 Department of Biochemistry and Biocenter Oulu University of Oulu Finland 3 Department of Pathology University of Oulu Finland Keywords channels membranes peroxisomes Saccharomyces cerevisiae yeast Correspondence V. D. Antonenkov Department of Biochemistry and Biocenter Oulu University of Oulu Linnanmaa PO Box 3000 FI-90014 Oulu Finland Fax 358 8 5531141 Tel 358 8 5531201 E-mail These authors contributed equally to this work Received 21 October 2008 revised 8 January 2009 accepted 12 January 2009 Highly-purified peroxisomes from the yeast Saccharomyces cerevisiae grown on oleic acid were investigated for the presence of channel pore -forming proteins in the membrane of these organelles. Solubilized membrane proteins were reconstituted in planar lipid bilayers and their pore-forming activity was studied by means of multiple-channel monitoring or singlechannel analysis. Two abundant pore-forming activities were detected with an average conductance of and nS in M KCl respectively. The high-conductance pore nS in M KCl is slightly selective to cations PK PC1- and showed an unusual flickering at elevated 40 mV holding potentials directed upward relative to the open state of the channel. The data obtained for the properties of the low-conductance pore nS in M KCl support the notion that the high-conductance channel represents a cluster of two low-conductance pores. The results lead to conclusion that the yeast peroxisomes contain membrane pore-forming proteins that may aid the transfer of small solutes between the peroxisomal lumen and cytoplasm. doi .

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