Homology between IRE-BP, a regulatory RNA-binding protein, aconitase, and isopropylmalate isomerase

Nucleic Acids Res. 1991 Apr 25;19(8):1739-40. doi: 10.1093/nar/19.8.1739.


Iron-responsive elements (IREs) are regulatory RNA elements which serve as specific binding sites for the IRE-binding protein (IRE-BP). Interaction between IREs and IRE-BP induces repression of ferritin mRNA translation and transferrin receptor mRNA stabilization. We describe the identification of extensive amino acid sequence homology between IRE-BP and two known isomerases, aconitase and isopropylmalate (IPM) isomerase. We discuss the implications of this observation with regard to structure/function relationships of IRE-BP. The structural conservation between a regulatory RNA-binding protein and two enzymes involved in intermediary metabolism provides a surprising example of the functional flexibility in biological structures.

MeSH terms

  • Aconitate Hydratase / genetics*
  • Aconitate Hydratase / metabolism
  • Amino Acid Sequence
  • Animals
  • Carrier Proteins / genetics*
  • Carrier Proteins / metabolism
  • Humans
  • Iron-Regulatory Proteins
  • Isomerases / genetics*
  • Isomerases / metabolism
  • Molecular Sequence Data
  • RNA, Messenger / metabolism*
  • RNA-Binding Proteins
  • Sequence Alignment
  • Sequence Homology, Nucleic Acid


  • Carrier Proteins
  • Iron-Regulatory Proteins
  • RNA, Messenger
  • RNA-Binding Proteins
  • Aconitate Hydratase
  • isopropylmalate isomerase
  • Isomerases