The RNase E of Escherichia coli is a membrane-binding protein

Mol Microbiol. 2008 Nov;70(4):799-813. doi: 10.1111/j.1365-2958.2008.06454.x. Epub 2008 Oct 2.


RNase E is an essential endoribonuclease involved in RNA processing and mRNA degradation. The N-terminal half of the protein encompasses the catalytic domain; the C-terminal half is the scaffold for the assembly of the multienzyme RNA degradosome. Here we identify and characterize 'segment-A', an element in the beginning of the non-catalytic region of RNase E that is required for membrane binding. We demonstrate in vitro that an oligopeptide corresponding to segment-A has the propensity to form an amphipathic alpha-helix and that it avidly binds to protein-free phospholipid vesicles. We demonstrate in vitro and in vivo that disruption of segment-A in full-length RNase E abolishes membrane binding. Taken together, our results show that segment-A is necessary and sufficient for RNase E binding to membranes. Strains in which segment-A has been disrupted grow slowly. Since in vitro experiments show that phospholipid binding does not affect the ribonuclease activity of RNase E, the slow-growth phenotype might arise from a defect involving processes such as accessibility to substrates or interactions with other membrane-bound machinery. This is the first report demonstrating that RNase E is a membrane-binding protein and that its localization to the inner cytoplasmic membrane is important for normal cell growth.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Calorimetry
  • Catalytic Domain
  • Cell Membrane / metabolism
  • Circular Dichroism
  • Endoribonucleases / genetics
  • Endoribonucleases / metabolism*
  • Escherichia coli / enzymology
  • Escherichia coli / genetics*
  • Escherichia coli / ultrastructure
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism*
  • Molecular Sequence Data
  • Multienzyme Complexes / genetics
  • Multienzyme Complexes / metabolism*
  • Mutation
  • Phospholipids / metabolism
  • Polyribonucleotide Nucleotidyltransferase / genetics
  • Polyribonucleotide Nucleotidyltransferase / metabolism*
  • Protein Binding
  • Protein Structure, Secondary
  • RNA Helicases / genetics
  • RNA Helicases / metabolism*
  • RNA, Bacterial / metabolism
  • Sequence Alignment


  • Bacterial Proteins
  • Escherichia coli Proteins
  • Multienzyme Complexes
  • Phospholipids
  • RNA, Bacterial
  • degradosome
  • Polyribonucleotide Nucleotidyltransferase
  • Endoribonucleases
  • ribonuclease E
  • RNA Helicases