Identification by Genetic Suppression of Escherichia coli TolB Residues Important for TolB-Pal Interaction
AUTOR(ES)
Ray, Marie-Céline
FONTE
American Society for Microbiology
RESUMO
The Tol-Pal system of Escherichia coli is involved in maintaining outer membrane stability. Mutations in tolQ, tolR, tolA, tolB, or pal genes result in sensitivity to bile salts and the leakage of periplasmic proteins. Moreover, some of the tol genes are necessary for the entry of group A colicins and the DNA of filamentous bacteriophages. TolQ, TolR, and TolA are located in the cytoplasmic membrane where they interact with each other via their transmembrane domains. TolB and Pal form a periplasmic complex near the outer membrane. We used suppressor genetics to identify the regions important for the interaction between TolB and Pal. Intragenic suppressor mutations were characterized in a domain of Pal that was shown to be involved in interactions with TolB and peptidoglycan. Extragenic suppressor mutations were located in tolB gene. The C-terminal region of TolB predicted to adopt a β-propeller structure was shown to be responsible for the interaction of the protein with Pal. Unexpectedly, none of the suppressor mutations was able to restore a correct association between Pal and peptidoglycan, suggesting that interactions between Pal and other components such as TolB may also be important for outer membrane stability.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=94349Documentos Relacionados
- Mutational Analysis of the TolA C-Terminal Domain of Escherichia coli and Genetic Evidence for an Interaction between 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.
- Maturation and localization of the TolB protein required for colicin import.
- Allosteric β-propeller signalling in TolB and its manipulation by translocating colicins