Ion channel formation by N-terminal domain: a common feature of OprFs of Pseudomonas and OmpA of Escherichia coli.
The proteolytic fragments of OprFs of Pseudomonas aeruginosa and Pseudomonas fluorescens were identified, respectively, as the first 175 and 177 amino acids from the N-terminal domain. They induced ion channels after reincorporation into planar lipid bilayers (85 and 75 pS, respectively, in 1 M NaCl). A similar conductance value (72 pS) was found for the eight beta-strand OmpA N-terminal domain (OmpA171) of Escherichia coli. We conclude that the N-terminal domain of OprFs is sufficient to induce ion channels and the comparison with OmpA171, provides strong evidence of the existence of an eight-stranded beta-barrel in the N-terminal domain of OprFs.
Saint
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UMR 6522 CNRS,Faculté des Sciences, Mont-Saint-Aignan, France. nathalie.saint@univ-rouen.fr
El Hamel
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Dé
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Molle
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D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D007473:Ion Channels / Q000378:metabolism*; D008051:Lipid Bilayers; D008969:Molecular Sequence Data; D018272:Porins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011549:Pseudomonas / Q000235:genetics / Q000378:metabolism*; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000378:metabolism; D011551:Pseudomonas fluorescens / Q000235:genetics / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D001425:Bacterial Outer Membrane Proteins; D007473:Ion Channels; D008051:Lipid Bilayers; D018272:Porins; C078167:OMPA outer membrane proteins