1. ompC mutants which allow growth on maltodextrins show increased channel size and greater voltage sensitivity
- Author
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Jeremy H. Lakey, Edward J.A. Lea, and Franc Pattus
- Subjects
Lipid Bilayers ,Molecular Sequence Data ,Mutant ,Biophysics ,Single-channel studies ,Porins ,Biology ,medicine.disease_cause ,Biochemistry ,Ion Channels ,Membrane Potentials ,chemistry.chemical_compound ,Polysaccharides ,Structural Biology ,Voltage dependence ,Sequence Homology, Nucleic Acid ,Escherichia coli ,Genetics ,medicine ,Maltotriose ,Amino Acid Sequence ,Molecular Biology ,Membrane potential ,Mutation ,Point mutation ,Wild type ,Conductance ,Cell Biology ,Thermal stability ,OmpC ,Culture Media ,chemistry ,Planar bilayers ,Electrophoresis, Polyacrylamide Gel ,Dex+ mutant ,Bacterial Outer Membrane Proteins - Abstract
Misra and Benson [(1988) J. Bacteriol. 170, 3611-3617] showed that point mutations in theompC gene can allowEscherichia coli to grow on maltotriose in the absence of LamB. This report shows that these mutants produce OmpC porins with increased single channel conductance compared to the wild type. The mutants showed similar voltage dependence to each other and to PhoE by being totally closed at 200 mV. The wild type from various sources was largely insensitive to voltages below 200 mV and thus 6 point mutations at 3 sites appear to increase the voltage dependence of OmpC channels.
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