PMID:12810711
| Citation |
Zhang, J, Zhang, Y and Inouye, M (2003) Characterization of the interactions within the mazEF addiction module of Escherichia coli. J. Biol. Chem. 278:32300-6 |
|---|---|
| Abstract |
In bacteria, programmed cell death is mediated through the unique genetic system called "addiction module," which consists of a pair of genes encoding a stable toxin and an unstable antitoxin. The mazEF system is known as an addiction module located on the Escherichia coli chromosome. MazF is a stable toxin, and MazE is a labile antitoxin interacting with MazF to form a complex. MazE and the MazE-MazF complex can bind to the mazEF promoter region to regulate the mazEF expression. Here we show that the binding of purified (His)6MazE to the mazEF promoter DNA was enhanced by MazF. The site-directed mutations at the conserved amino acid residues in MazE N-terminal region (K7A, R8A, S12A, and R16A) disrupted the DNA binding ability of both (His)6MazE and the MazE-MazF-(His)6 complex, suggesting that MazE binds to the mazEF promoter DNA through the N-terminal domain. The ratio of MazE to MazF(His)6 in the MazE-MazF(His)6 complex is about 1:2. Because both MazE and MazF-(His)6 exist as dimers by themselves, the MazE-MazF-(His)6 complex (76.9 kDa) is predicted to consist of one MazE dimer and two MazF(His)6 dimers. The interaction between MazE and MazF was also characterized with the yeast two-hybrid system. It was found that the region from residues 38 to 75 of MazE was required for its binding to MazF. Site-directed mutagenesis at this region revealed that Leu55 and Leu58 play an important role in the MazE-MazF complex formation but not in MazE binding to the mazEF promoter DNA. The present results demonstrate that MazE is composed of two domains, the N-terminal DNA-binding domain and the C-terminal domain interacting with MazF. |
| Links |
PubMed Online version:10.1074/jbc.M304767200 |
| Keywords |
Amino Acid Sequence; Chromosomes, Bacterial; DNA, Bacterial/metabolism; DNA-Binding Proteins/chemistry; DNA-Binding Proteins/genetics; DNA-Binding Proteins/metabolism; Electrophoresis, Polyacrylamide Gel; Electrophoretic Mobility Shift Assay; Endoribonucleases; Escherichia coli/genetics; Escherichia coli Proteins; Genes, Bacterial; Molecular Sequence Data; Mutagenesis, Site-Directed; Promoter Regions, Genetic; Protein Binding; Sequence Homology, Amino Acid |
| 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.