This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Pi, J.
Right arrow Articles by Pittard, A. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Pi, J.
Right arrow Articles by Pittard, A. J.

 Previous Article  |  Next Article 

Journal of Bacteriology, November 1998, p. 5515-5519, Vol. 180, No. 21
0021-9193/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.

Functional Consequences of Changing Proline Residues in the Phenylalanine-Specific Permease of Escherichia coli

Jing Pi, C. Dogovski, and A. J. Pittard*

Department of Microbiology and Immunology, The University of Melbourne, Parkville, Victoria 3052, Australia

Received 12 June 1998/Accepted 31 August 1998

The PheP protein is a high-affinity phenylalanine-specific permease of the bacterium Escherichia coli. A topological model based on genetic analysis involving the construction of protein fusions with alkaline phosphatase has previously been proposed in which PheP has 12 transmembrane segments with both N and C termini located in the cytoplasm (J. Pi and A. J. Pittard, J. Bacteriol. 178:2650-2655, 1996). Site-directed mutagenesis has been used to investigate the functional importance of each of the 16 proline residues of the PheP protein. Replacement of alanine at only three positions, P54, P341, and P442, resulted in the loss of 50% or more activity. Substitutions at P341 had the most dramatic effects. None of these changes in transport activity were, however, associated with any defect of the mutant protein in inserting into the membrane, as indicated by [35S]methionine labelling and immunoprecipitation using anti-PheP serum. A possible role for each of these three prolines is discussed. Inserting a single alanine residue at different sites within span IX and the loop immediately preceding it also had major effects on transport activity, suggesting an important role for a highly organized structure in this region of the protein.

* Corresponding author. Mailing address: Department of Microbiology, The University of Melbourne, Parkville, Victoria 3052, Australia. Phone: (613) 9344 5679. Fax: (613) 9347 1540. E-mail: jingwoo{at}ariel.ucs.unimelb.edu.au.

Journal of Bacteriology, November 1998, p. 5515-5519, Vol. 180, No. 21
0021-9193/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.


This article has been cited by other articles:

  • Cruz-Ramos, H., Cook, G. M., Wu, G., Cleeter, M. W., Poole, R. K. (2004). Membrane topology and mutational analysis of Escherichia coli CydDC, an ABC-type cysteine exporter required for cytochrome assembly. Microbiology 150: 3415-3427 [Abstract] [Full Text]  
  • Dogovski, C., Pi, J., Pittard, A. J. (2003). Putative Interhelical Interactions within the PheP Protein Revealed by Second-Site Suppressor Analysis. J. Bacteriol. 185: 6225-6232 [Abstract] [Full Text]  
  • Pi, J., Chow, H., Pittard, A. J. (2002). Study of Second-Site Suppression in the pheP Gene for the Phenylalanine Transporter of Escherichia coli. J. Bacteriol. 184: 5842-5847 [Abstract] [Full Text]  
  • Cosgriff, A. J., Brasier, G., Pi, J., Dogovski, C., Sarsero, J. P., Pittard, A. J. (2000). A Study of AroP-PheP Chimeric Proteins and Identification of a Residue Involved in Tryptophan Transport. J. Bacteriol. 182: 2207-2217 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»