Sequence analysis of twin ATP binding cassette proteins involved in translational control, antibiotic resistance, and ribonuclease L inhibition

Biochem Biophys Res Commun. 2004 Feb 27;315(1):166-73. doi: 10.1016/j.bbrc.2004.01.044.


Genome sequencing has identified open reading frames which belong to the ATP binding cassette (ABC) transporter family, but which are unlikely to be involved in transport phenomena. These frequently contain a pair of nucleotide binding domains (NBD) with no associated transmembrane domains. The functions of many of these twin-NBD proteins remain unknown. In this manuscript, sequence analysis has been employed to analyse two families of twin-NBD proteins, ABCE and ABCF. The ABCE proteins, postulated to be inhibitors of RNase L, are identified by two potential Fe-S metal-binding domains in addition to two NBDs. Surprisingly, ABCE homologues are identified in numerous species which apparently lack an RNase L, questioning the proposed function of these proteins. The ABCF proteins can be sub-divided into more than a dozen sub-classes. Intriguingly, sequence similarity is shown between eukaryotic ABCF proteins, which are involved in translation initiation and elongation, and prokaryotic ABCF proteins which are implicated in resistance to macrolide inhibitors of protein synthesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP-Binding Cassette Transporters / chemistry
  • ATP-Binding Cassette Transporters / classification
  • ATP-Binding Cassette Transporters / genetics*
  • ATP-Binding Cassette Transporters / physiology
  • Amino Acid Motifs
  • Amino Acid Sequence
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / classification
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Chaperonins / genetics*
  • Drug Resistance / genetics*
  • Eukaryotic Cells / chemistry
  • Humans
  • Molecular Sequence Data
  • Open Reading Frames / genetics
  • Phylogeny
  • Protein Biosynthesis / genetics*
  • Protein Structure, Tertiary
  • Sequence Alignment
  • Sequence Homology, Amino Acid


  • ABCE1 protein, human
  • ATP-Binding Cassette Transporters
  • Bacterial Proteins
  • Chaperonins