PMID:8702817
| Citation |
Saint, N, Lou, KL, Widmer, C, Luckey, M, Schirmer, T and Rosenbusch, JP (1996) Structural and functional characterization of OmpF porin mutants selected for larger pore size. II. Functional characterization. J. Biol. Chem. 271:20676-80 |
|---|---|
| Abstract |
The effects on the channel characteristics of four single amino acid substitutions in OmpF porin and of a deletion mutant in the constriction loop L3 have been studied. These mutations are all located in the narrow section of the channel of the protein that forms pores across the outer membrane of Escherichia coli. The single channel conductance of the deletion mutant (Delta109-114) is decreased by one third, whereas the point mutations do not exhibit significant deviations from that of the wild-type protein. The mutants exhibit drastic changes in ion selectivities. In the wild-type protein, the critical threshold potential (Vc), above which channels close reversibly, exhibits a strong pH dependence, with a titration point of approximately pH 7.7, which is abolished in all mutants studied here. Diffusion of six monosaccharides is little affected in the point mutants, while four disaccharides are taken up at highly increased rates by the deletion mutant. The functional results, presented here, are correlated to the x-ray structures of the mutants (Lou, K.-L., Saint, N., Prilipov, A., Rummel, G., Benson, S.A., Rosenbusch, J.P., and Schirmer, T. (1996) J. Biol. Chem. 271, 20669-20675). In most, but not all, cases, the structural changes explain the functional alterations observed. |
| Links | |
| Keywords |
Bacterial Outer Membrane Proteins/physiology; Biological Transport; Carbohydrate Metabolism; Diffusion; Disaccharides/metabolism; Electric Conductivity; Escherichia coli; Hydrogen-Ion Concentration; Ion Channel Gating; Ion Channels/physiology; Lipid Bilayers; Membrane Potentials; Membranes, Artificial; Recombinant Proteins; Structure-Activity Relationship |
| edit table |
Significance
You can help EcoliWiki by summarizing why this paper is useful
Useful Materials and Methods
You can help Ecoliwiki by describing the useful materials (strains, plasmids, antibodies, etc) described in this paper.
Annotations
<annotationlinks/>
EcoliWiki Links
Add links to pages that link here (e.g. gene, product, method pages)
References
See Help:References for how to manage references in EcoliWiki.
