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Channel‐forming activities of peroxisomal membrane proteins from the yeast Saccharomyces cerevisiae
Author(s) -
Grunau Silke,
Mindthoff Sabrina,
Rottensteiner Hanspeter,
Sormunen Raija T.,
Hiltunen J. Kalervo,
Erdmann Ralf,
Antonenkov Vasily D.
Publication year - 2009
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2009.06903.x
Subject(s) - conductance , saccharomyces cerevisiae , membrane , yeast , peroxisome , chemistry , cytoplasm , spheroplast , organelle , biophysics , lipid bilayer , membrane protein , biochemistry , crystallography , biology , mathematics , escherichia coli , combinatorics , gene
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 single‐channel analysis. Two abundant pore‐forming activities were detected with an average conductance of 0.2 and 0.6 nS in 1.0 m KCl, respectively. The high‐conductance pore (0.6 nS in 1.0 m KCl) is slightly selective to cations ( P K+ / P Cl− ∼ 1.3) 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 (0.2 nS in 1.0 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.