The LIM region of a presumptive Caenorhabditis elegans transcription factor is an iron-sulfur- and zinc-containing metallodomain.
The cysteine-rich LIM motif is highly conserved between invertebrates and mammals. This motif shows similarity both to proteins that bind zinc and to ferredoxins, which contain iron-sulfur clusters. Two tandem copies of the LIM motif are found in a number of presumptive transcription factors, including the protein product of the Caenorhabditis elegans cell-lineage gene lin-11. To investigate the possible metal-binding properties of the LIM region of the lin-11 protein, we expressed and purified a 151-amino acid peptide containing the tandem LIM motifs. The purified peptide binds both zinc (two atoms per protein molecule) and iron (as a redox-active iron-sulfur cluster, with four atoms of iron and four atoms of inorganic sulfide per protein molecule). These observations suggest that the LIM motif is a metallodomain that might function in a redox-sensitive regulation of transcription.
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02215.
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Li
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Reichert
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Freyd
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Horvitz
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Walsh
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002107:Caenorhabditis / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D007506:Iron-Sulfur Proteins / Q000235:genetics* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009841:Oligonucleotides; D010446:Peptide Fragments / Q000302:isolation & purification; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000302:isolation & purification; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D013053:Spectrophotometry; D014157:Transcription Factors / Q000235:genetics* / Q000302:isolation & purification; D016335:Zinc Fingers / Q000235:genetics*
D007506:Iron-Sulfur Proteins; D009841:Oligonucleotides; D010446:Peptide Fragments; D011994:Recombinant Proteins; D014157:Transcription Factors