title: Homology between IRE-BP, a regulatory RNA-binding protein, aconitase, and isopropylmalate isomerase.
abstract: 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.
authors.affiliation: European Molecular Biology Laboratory, Heidelberg, FRG.
authors.forename: M W
authors.initials: MW
authors.lastname: Hentze
authors.forename: P
authors.initials: P
authors.lastname: Argos
mesh_terms: D000154:Aconitate Hydratase / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D035925:Iron-Regulatory Proteins; D007535:Isomerases / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid
chemical_list: D002352:Carrier Proteins; D035925:Iron-Regulatory Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D000154:Aconitate Hydratase; C032241:isopropylmalate isomerase; D007535:Isomerases