Channel-forming activities of peroxisomal membrane proteins from the yeast Saccharomyces cerevisiae.
FEBS J
; 276(6): 1698-708, 2009 Mar.
Article
em En
| MEDLINE
| ID: mdl-19220856
ABSTRACT
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-) approximately 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.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Peroxissomos
/
Proteínas de Saccharomyces cerevisiae
/
Canais Iônicos
Idioma:
En
Ano de publicação:
2009
Tipo de documento:
Article