The ABC-F protein EttA gates ribosome entry into the translation elongation cycle

Nat Struct Mol Biol. 2014 Feb;21(2):143-51. doi: 10.1038/nsmb.2740. Epub 2014 Jan 5.


ABC-F proteins have evaded functional characterization even though they compose one of the most widely distributed branches of the ATP-binding cassette (ABC) superfamily. Herein, we demonstrate that YjjK, the most prevalent eubacterial ABC-F protein, gates ribosome entry into the translation elongation cycle through a nucleotide-dependent interaction sensitive to ATP/ADP ratio. Accordingly, we rename this protein energy-dependent translational throttle A (EttA). We determined the crystal structure of Escherichia coli EttA and used it to design mutants for biochemical studies including enzymological assays of the initial steps of protein synthesis. These studies suggest that EttA may regulate protein synthesis in energy-depleted cells, which have a low ATP/ADP ratio. Consistently with this inference, EttA-deleted cells exhibit a severe fitness defect in long-term stationary phase. These studies demonstrate that an ABC-F protein regulates protein synthesis via a new mechanism sensitive to cellular energy status.

Publication types

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

MeSH terms

  • ATP-Binding Cassette Transporters / chemistry
  • ATP-Binding Cassette Transporters / metabolism
  • ATP-Binding Cassette Transporters / physiology*
  • Crystallography, X-Ray
  • Escherichia coli Proteins / chemistry
  • Escherichia coli Proteins / metabolism
  • Escherichia coli Proteins / physiology*
  • Models, Biological
  • Models, Molecular
  • Peptide Chain Elongation, Translational*
  • Phylogeny
  • Protein Structure, Tertiary
  • Ribosomes / metabolism*


  • ATP-Binding Cassette Transporters
  • Escherichia coli Proteins
  • EttA protein, E coli

Associated data

  • PDB/4FIN