Channel‐forming properties and structural homology of major outer membrane proteins from Pseudomonas fluorescens MFO and OE 28.3

• Published in: FEMS microbiology letters 1995-04, Vol.127 (3), p.267-272
• Main Authors: Dé, Emmanuelle, Mot, René, Orange, Nicole, Saint, Nathalie, Molle, Gérard
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Bacteriology; Biological and medical sciences; Cattle; Channel‐forming properties; DNA sequence; Electric Conductivity; Fundamental and applied biological sciences. Psychology; Ion Channels - chemistry; Ion Channels - genetics; Ion Channels - metabolism; Lipid Bilayers; Major outer membrane protein; Microbiology; Milk - microbiology; Molecular Sequence Data; Molecular Structure; OprF; Permeability, membrane transport, intracellular transport; Polymerase Chain Reaction; Porins - chemistry; Porins - genetics; Porins - metabolism; Pseudomonas fluorescens; Pseudomonas fluorescens - genetics; Pseudomonas fluorescens - isolation & purification; Pseudomonas fluorescens - metabolism; Sequence Homology, Amino Acid; Soil Microbiology; Species Specificity
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1111/j.1574-6968.1995.tb07484.x

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 l 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).