A shared, non-canonical DNA conformation detected at DNA/protein contact sites and bent DNA in the absence of supercoiling or cognate protein binding.
A hybrid protein (H144), consisting of Lac repressor and T7 endonuclease I, binds at the lac operator and cleaves relaxed double-stranded DNA at distal but distinct sites. These sites are shown here to coincide with a bacterial promoter, a phage T7 promoter, a site for gyrase and intrinsically bent DNA. The targets do not seem to share a particular DNA sequence, and in bent DNA, cleavage occurs at the physical center rather than at the common A-tracts. These results indicate that protein contact sites and intrinsic bends assume a non-canonical conformation in the absence of supercoiling or cognate protein binding. This feature may serve as a recognition signal or facilitate protein binding to initiate transcription and recombination.
Economides
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REGENERON Pharmaceuticals Inc., Tarrytown, New York 10591-6707, USA.
Everdeen
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D
Panayotatos
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N
D001483:Base Sequence; D004274:DNA, Recombinant / Q000737:chemistry*; D004278:DNA, Superhelical / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D012045:Regulatory Sequences, Nucleic Acid; D018741:Replication Origin
D004274:DNA, Recombinant; D004278:DNA, Superhelical; D004268:DNA-Binding Proteins