Channel-forming properties and structural homology of major outer membrane proteins from Pseudomonas fluorescens MFO and OE 28.3.
The major outer membrane proteins (OprF) from Pseudomonas fluorescens MFO and OE 28.3 were purified by a new method involving native electrophoresis in octyl-polyoxyethylene media. Both proteins, characterized by the same size, heat-modifiability and N-terminal sequence were re-incorporated in virtually solvent-free planar lipid bilayers. They displayed very similar channel-forming properties: the major conductance level was between 250 pS and 270 pS in 1 M NaCl. From experiments of zero-current potential, both porins were determined weakly cation selective. Amplification by PCR and sequencing of the oprF gene of strain MFO allowed to point out 94% identity between the amino acid sequences of these two OprFs isolated from ecological niches as different as milk (strain MFO) and soil (strain OE 28.3).
Dé
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URA 500 CNRS, Faculté des Sciences de Rouen, Mont-Saint-Aignan, France.
De Mot
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Orange
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Saint
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Molle
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D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D004553:Electric Conductivity; D007473:Ion Channels / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008051:Lipid Bilayers; D008892:Milk / Q000382:microbiology; D008969:Molecular Sequence Data; D015394:Molecular Structure; D016133:Polymerase Chain Reaction; D018272:Porins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011551:Pseudomonas fluorescens / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D012988:Soil Microbiology; D013045:Species Specificity
D007473:Ion Channels; D008051:Lipid Bilayers; D018272:Porins