An unusually stable DNA binding protein can locate its specific binding site in the presence of high concentrations of urea.
A sequence specific DNA binding protein has been demonstrated in extracts of Drosophila melanogaster third instar larval nuclei which binds close to a chromosome-scaffold associated region. This protein has proven difficult to work with because of its strong tendency to aggregate. Here I show that the protein can be readily maintained in solution in the presence of high concentrations of urea. Surprisingly, the protein turns out to be remarkably resistant to denaturation by urea. It is capable of mediating sequence specific DNA binding in the presence of urea at concentrations up to 8M. When incubated in 4M urea the binding activity appears to slowly degrade, but in 1.3M urea the protein is active, soluble and stable over extended periods of time at room temperature. The molecular basis of this unexpected finding must await the purification of the protein. The ability to keep the protein both soluble and active should now permit its isolation.
Jack
R S
RS
Institut für Genetik, der Universität zu Köln, FRG.
D000818:Animals; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster; D066298:In Vitro Techniques; D009687:Nuclear Proteins / Q000378:metabolism*; D011489:Protein Denaturation / Q000187:drug effects; D014508:Urea / Q000494:pharmacology*
D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D014508:Urea; D004247:DNA