Characterization of the tol-pal region of Escherichia coli K-12: translational control of tolR expression by TolQ and identification of a new open reading frame downstream of pal encoding a periplasmic protein

J Bacteriol. 1996 Jul;178(14):4031-8. doi: 10.1128/jb.178.14.4031-4038.1996.

Abstract

The TolQ, TolR, TolA, TolB, and Pal proteins appear to function in maintaining the integrity of the outer membrane, as well as facilitating the uptake of the group A colicins and the DNA of the infecting filamentous bacteriophages. Sequence data showed that these genes are clustered in a 6-kb segment of DNA with the gene order orf1 tolQ tolR tolA tolB pal orf2 (a newly identified open reading frame encoding a 29-kD9 protein). Like those containing orf1, bacteria containing an insertion mutation in this gene showed no obvious phenotype. Analysis of beta-galactosidase activity from fusion constructs in which the lac operon was fused to various genes in the cluster showed that the genes in this region constitute two separate operons: orf1 tolQRA and tolB pal orf2. In the orf1 tolQRA operon, translation of MR was dependent on translation of the upstream tolQ region. Consistent with this result, no functional ribosome-binding site for TolR synthesis was detected.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism
  • Base Sequence
  • Cloning, Molecular
  • Escherichia coli / genetics*
  • Escherichia coli Proteins*
  • Gene Expression Regulation, Bacterial*
  • Genetic Complementation Test
  • Membrane Proteins / genetics*
  • Membrane Proteins / metabolism
  • Molecular Sequence Data
  • Mutagenesis, Insertional
  • Open Reading Frames
  • Operon
  • Protein Biosynthesis*
  • Sequence Homology, Amino Acid
  • Species Specificity
  • Transcription, Genetic

Substances

  • Bacterial Proteins
  • Escherichia coli Proteins
  • Membrane Proteins
  • tolQ protein, E coli
  • tolR protein, E coli