Maturation and localization of the TolB protein required for colicin import.

AUTOR(ES)

Isnard, M

RESUMO

The tolB gene has been shown previously to encode two proteins of 47.5 kDa (TolB) and 43 kDa (TolB*). To explain the presence of these two forms, two hypotheses have been proposed: TolB might be posttranslationally processed to TolB*, or an internal in-frame translation initiation resulting in TolB* may occur (S. K. Levengood and R. E. Webster, J. Bacteriol. 171:6600-6609, 1989). To address this question, TolB was tagged by inserting in its C-terminal region an epitope recognized by monoclonal antibody 1C11 without altering the function of TolB. It was then demonstrated that the functional protein corresponded to TolB*, the mature periplasmic protein, and that TolB was its precursor form, which was observed only when the protein was overexpressed. These two forms were purified by immunoprecipitation, and their N-terminal sequences were determined. An antibody directed against TolB was raised, which confirmed the results obtained with the tagged TolB.

Documentos Relacionados

• fii, a bacterial locus required for filamentous phage infection and its relation to colicin-tolerant tolA and tolB.
• The TolB protein interacts with the porins of Escherichia coli.
• Nucleotide sequences of the tolA and tolB genes and localization of their products, components of a multistep translocation system in Escherichia coli.
• Identification by Genetic Suppression of Escherichia coli TolB Residues Important for TolB-Pal Interaction
• Mutational Analysis of the TolA C-Terminal Domain of Escherichia coli and Genetic Evidence for an Interaction between TolA and TolB