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 Niemeyer, D.
Right arrow Articles by Becker, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Niemeyer, D.
Right arrow Articles by Becker, A.

 Previous Article  |  Next Article 

Journal of Bacteriology, September 2001, p. 5163-5170, Vol. 183, No. 17
0021-9193/01/$04.00+0   DOI: 10.1128/JB.183.17.5163-5170.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.

The Molecular Weight Distribution of Succinoglycan Produced by Sinorhizobium meliloti Is Influenced by Specific Tyrosine Phosphorylation and ATPase Activity of the Cytoplasmic Domain of the ExoP Protein

Dagmar Niemeyer and Anke Becker*

Lehrstuhl für Genetik, Fakultät für Biologie, Universität Bielefeld, D-33501 Bielefeld, Germany

Received 12 March 2001/Accepted 6 June 2001

It is thought that in the gram-negative soil bacterium Sinorhizobium meliloti the protein ExoP is involved in biosynthesis of the acidic exopolysaccharide succinoglycan (EPS I). The amounts and compositions of EPS I produced by mutants expressing ExoP proteins characterized by specific amino acid substitutions in the C-terminal cytoplasmic domain were analyzed. The cytoplasmic domain of the ExoP protein was shown to have ATPase activity. Mutations in the highly conserved Walker A ATP-binding motif prevented ATPase activity of the ExoP protein. Phenotypically, these mutations resulted in much lower levels of succinoglycan which consisted only of monomers of the octasaccharide repeating unit. The ExoP protein has similarities to proteins with autophosphorylating protein tyrosine kinase activity. We found that ExoP was phosphorylated on tyrosine and that site-directed mutagenesis of specific tyrosine residues in the cytoplasmic domain of ExoP resulted in an altered ratio of low-molecular-weight succinoglycan to high-molecular-weight succinoglycan.

* Corresponding author. Mailing address: Lehrstuhl für Genetik, Fakultät für Biologie, Universität Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany. Phone: 49 521 106-4824. Fax: 49 521 106-5626. E-mail: Anke.Becker{at}genetik.uni-bielefeld.de.

Journal of Bacteriology, September 2001, p. 5163-5170, Vol. 183, No. 17
0021-9193/01/$04.00+0   DOI: 10.1128/JB.183.17.5163-5170.2001
Copyright © 2001, 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 © 2001 by the American Society for Microbiology. All rights reserved.