Z-DNA binding protein from chicken blood nuclei.
A protein (Z alpha) that appears to be highly specific for the left-handed Z-DNA conformer has been identified in chicken blood nuclear extracts. Z alpha activity is measured in a band-shift assay by using a radioactive probe consisting of a (dC-dG)35 oligomer that has 50% of the deoxycytosines replaced with 5-bromodeoxycytosine. In the presence of 10 mM Mg2+, the probe converts to the Z-DNA conformation and is bound by Z alpha. The binding of Z alpha to the radioactive probe is specifically blocked by competition with linear poly(dC-dG) stabilized in the Z-DNA form by chemical bromination but not by B-form poly(dC-dG) or boiled salmon-sperm DNA. In addition, the binding activity of Z alpha is competitively blocked by supercoiled plasmids containing a Z-DNA insert but not by either the linearized plasmid or by an equivalent amount of the parental supercoiled plasmid without the Z-DNA-forming insert. Z alpha can be crosslinked to the 32P-labeled brominated probe with UV light, allowing us to estimate that the minimal molecular mass of Z alpha is 39 kDa.
Herbert
A G
AG
Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
Spitzner
J R
JR
Lowenhaupt
K
K
Rich
A
A
D000818:Animals; D001773:Blood Cells / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism*; D002645:Chickens; D003432:Cross-Linking Reagents; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000097:blood* / Q000302:isolation & purification; D004591:Electrophoresis, Polyacrylamide Gel; D008970:Molecular Weight; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis / Q000378:metabolism; D015345:Oligonucleotide Probes
D003432:Cross-Linking Reagents; D004268:DNA-Binding Proteins; D009838:Oligodeoxyribonucleotides; D015345:Oligonucleotide Probes; D004247:DNA