title: Metal-dependent folding of a single zinc finger from transcription factor IIIA.
abstract: A 30-amino acid peptide, which corresponds to the second "zinc finger" domain of transcription factor IIIA, has been synthesized and purified. This peptide folds in the presence of zinc: adding Zn2+ significantly changes the circular dichroism spectrum, and Zn2+ protects the peptide from tryptic digestion. The peptide also binds Co2+, and the absorption spectrum of the Co2+ complex suggests that a tetrahedral binding site is formed by two cysteines and two histidines. Experiments at higher temperatures (60-75 degrees C) suggest that these folded metal-peptide complexes are quite thermostable. The peptide shows some sequence-specific effects in DNase and methylation protection experiments. However, it does not give a clear "footprint," and some effects are observed in the absence of added zinc.
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002942:Circular Dichroism; D003035:Cobalt / Q000378:metabolism / Q000494:pharmacology; D004275:DNA, Ribosomal / Q000378:metabolism; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000378:metabolism; D011487:Protein Conformation / Q000187:drug effects; D012335:RNA, Ribosomal / Q000235:genetics; D011994:Recombinant Proteins; D013696:Temperature; D035582:Transcription Factor TFIIIA; D014157:Transcription Factors / Q000138:chemical synthesis / Q000378:metabolism; D015032:Zinc / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D004275:DNA, Ribosomal; D010446:Peptide Fragments; D012335:RNA, Ribosomal; D011994:Recombinant Proteins; D035582:Transcription Factor TFIIIA; D014157:Transcription Factors; D003035:Cobalt; D015032:Zinc