PMID:12374816

Pi, J, Chow, H and Pittard, AJ (2002) Study of second-site suppression in the pheP gene for the phenylalanine transporter of Escherichia coli.J. Bacteriol. 184:5842-7

Abstract

Site-directed mutagenesis was used to investigate a region of the PheP protein corresponding to the postulated consensus amphipathic region (CAR) in the GabP protein. Whereas some critical residues are conserved in both proteins, there are major differences between the two proteins which may reflect different functions for this region. Replacement of R317, Y313, or P341 by a number of other amino acids destroyed the PheP function. An R317E-E234R double mutant exhibited low levels of PheP transport activity, indicating that there is a possible interaction between these two residues in the wild-type protein. E234 is highly conserved in members of the superfamily of amino acid-polyamine-organocation transporters and also is critical for PheP function in the wild-type protein. Second-site suppressors were isolated for mutants with mutations in E234, Y313, R317, and P341. Most suppressor mutations were found to cluster towards the extracellular face of spans III, IX, and X. Some mutations, such as changes at M116, were able to suppress each of the primary changes at positions E234, Y313, R317, and P341 but were unable to restore function to a number of other primary mutants. The possible implications of these results for the tertiary structure of the protein are discussed.

Links

PubMed

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

Gene product	Qualifier	GO ID	GO term name	Evidence Code	with/from	Aspect	Notes	Status
edit table

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.