JB
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
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 Zeppenfeld, T.
Right arrow Articles by Jahreis, K.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Zeppenfeld, T.
Right arrow Articles by Jahreis, K.

 Previous Article  |  Next Article 

Journal of Bacteriology, August 2000, p. 4443-4452, Vol. 182, No. 16
0021-9193/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.

Glucose Transporter Mutants of Escherichia coli K-12 with Changes in Substrate Recognition of IICBGlc and Induction Behavior of the ptsG Gene

Tim Zeppenfeld, Christina Larisch, Joseph W. Lengeler, and Knut Jahreis*

Arbeitsgruppe Genetik, Fachbereich Biologie/Chemie, Universität Osnabrück, D-49069 Osnabrück, Germany

Received 31 March 2000/Accepted 22 May 2000

In Escherichia coli K-12, the major glucose transporter with a central role in carbon catabolite repression and in inducer exclusion is the phosphoenolpyruvate-dependent glucose:phosphotransferase system (PTS). Its membrane-bound subunit, IICBGlc, is encoded by the gene ptsG; its soluble domain, IIAGlc, is encoded by crr, which is a member of the pts operon. The system is inducible by D-glucose and, to a lesser degree, by L-sorbose. The regulation of ptsG transcription was analyzed by testing the induction of IICBGlc transporter activity and of a single-copy Phi (ptsGop-lacZ) fusion. Among mutations found to affect directly ptsG expression were those altering the activity of adenylate cyclase (cyaA), the repressor DgsA (dgsA; also called Mlc), the general PTS proteins enzyme I (ptsI) and histidine carrier protein HPr (ptsH), and the IIAGlc and IIBGlc domains, as well as several authentic and newly isolated UmgC mutations. The latter, originally thought to map in the repressor gene umgC outside the ptsG locus, were found to represent ptsG alleles. These affected invariably the substrate specificity of the IICBGlc domain, thus allowing efficient transport and phosphorylation of substrates normally transported very poorly or not at all by this PTS. Simultaneously, all of these substrates became inducers for ptsG. From the analysis of the mutants, from cis-trans dominance tests, and from the identification of the amino acid residues mutated in the UmgC mutants, a new regulatory mechanism involved in ptsG induction is postulated. According to this model, the phosphorylation state of IIBGlc modulates IICGlc which, directly or indirectly, controls the repressor DgsA and hence ptsG expression. By the same mechanism, glucose uptake and phosphorylation also control the expression of the pts operon and probably of all operons controlled by the repressor DgsA.

* Corresponding author. Mailing address: Arbeitsgruppe Genetik, Fachbereich Biologie/Chemie, Universität Osnabrück, D-49069 Osnabrück, Germany. Phone: 49-541-969-2288. Fax: 49-541-969-2293. E-mail: Jahreis{at}Biologie.Uni-Osnabrueck.de.

Journal of Bacteriology, August 2000, p. 4443-4452, Vol. 182, No. 16
0021-9193/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.


This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
Appl. Environ. Microbiol. Infect. Immun. Eukaryot. Cell
Mol. Cell. Biol. J. Virol. Microbiol. Mol. Biol. Rev.
ALL ASM JOURNALS

Copyright © 2000 by the American Society for Microbiology. All rights reserved.