PMID:7898450
| Citation |
Haardt, M, Kempf, B, Faatz, E and Bremer, E (1995) The osmoprotectant proline betaine is a major substrate for the binding-protein-dependent transport system ProU of Escherichia coli K-12. Mol. Gen. Genet. 246:783-6 |
|---|---|
| Abstract |
The ProP and ProU transport systems of Escherichia coli mediate the uptake of several osmoprotectants including glycine betaine. Here we report that both ProP and ProU are involved in the transport of the potent osmoprotectant proline betaine. A set of isogenic E. coli strains carrying deletions in either the proP or proU loci was constructed. The growth properties of these mutants in high osmolarity minimal media containing 1 mM proline betaine demonstrated that the osmoprotective effect of this compound was dependent on either an intact ProP or ProU uptake system. Proline betaine competes with glycine betaine for binding to the proU-encoded periplasmic substrate binding protein (ProX) and we estimate a KD of 5.2 microM for proline betaine binding. This value is similar to the binding constant of the ProX protein determined previously for the binding of glycine betaine (KD of 1.4 microM). Our results thus demonstrate that the binding-protein-dependent ProU transport system of E. coli mediates the efficient uptake of the osmoprotectants glycine betaine and proline betaine. |
| Links | |
| Keywords |
Amino Acid Transport Systems; Bacterial Proteins/genetics; Bacterial Proteins/metabolism; Betaine/metabolism; Biological Transport; Carrier Proteins/genetics; Carrier Proteins/metabolism; Escherichia coli/metabolism; Escherichia coli Proteins; Gene Deletion; Osmotic Pressure; Proline/analogs & derivatives; Proline/metabolism; Protein Binding; Symporters |
| 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.