Identification by genetic suppression of Escherichia coli TolB residues important for TolB-Pal interaction - PubMed (original) (raw)

Identification by genetic suppression of Escherichia coli TolB residues important for TolB-Pal interaction

M C Ray et al. J Bacteriol. 2000 Feb.

Abstract

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 beta-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.

PubMed Disclaimer

Figures

FIG. 1

FIG. 1

Alignment of repeats found in the C-terminal domain of E. coli TolB. The positions of residues involved in suppressor mutations of pal A88V are shaded in black. The four β-strands are indicated above the alignment, as shown by Ponting and Pallen (19). The consensus sequence was defined by specific amino acids appearing more than three times at the same position.

Similar articles

Cited by

References

    1. Abergel C, Rigal A, Chenivesse S, Lazdunski C, Claverie J M, Bouveret E, Bénédetti H. Crystallization and preliminary crystallographic study of a component of the Escherichia coli tol system: TolB. Acta Crystallogr Sect D Biol Crystallogr. 1998;54:102–104. - PubMed
    1. Bernadac A, Gavioli M, Lazzaroni J C, Raina S, Lloubès R. Escherichia coli tol-pal mutants form outer membrane vesicles. J Bacteriol. 1998;180:4872–4878. - PMC - PubMed
    1. Birnboim H C, Doly J. A rapid alkaline extraction procedure for screening recombinant plasmid DNA. Nucleic Acids Res. 1979;7:1513. - PMC - PubMed
    1. Bouveret E, Derouiche R, Rigal A, Lloubès R, Lazdunski C, Bénédetti H. Peptidoglycan associated lipoprotein (Pal)-TolB interaction; a possible key for explaining the formation of contact sites between the inner and outer membranes of Escherichia coli. J Biol Chem. 1995;270:11071–11077. - PubMed
    1. Bouveret E, Bénédetti H, Rigal A, Loret E, Lazdunski C. In vitro characterization of the peptidoglycan-associated lipoprotein (PAL)-peptidoglycan and PAL-TolB interactions. J Bacteriol. 1999;181:6306–6311. - PMC - PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources