DNA loops induced by cooperative binding of lambda repressor.

J Griffith; A Hochschild; M Ptashne

doi:10.1038/322750a0

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DNA loops induced by cooperative binding of lambda repressor.

J Griffith·A Hochschild·M Ptashne

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Abstract

It has been shown by Hochschild and Ptashne that lambda repressors bind cooperatively to operator sites separated by five or six turns of the helix. Cooperative binding is not observed if the sites are separated by a nonintegral number of turns, unless a four-nucleotide gap is introduced into one of the strands between the two sites. These and other facts suggested that repressors at the separated sites touch each other, the DNA bending smoothly so as to accommodate the protein-protein interaction. Here we use electron microscopy to visualize the predicted protein-DNA complexes.

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Binding Sites DNA, Viral DNA-Binding Proteins Microscopy, Electron Nucleic Acid Conformation Operator Regions, Genetic Protein Binding Protein Conformation Repressor Proteins Transcription Factors Viral Proteins Viral Regulatory and Accessory Proteins Journal Article Research Support, U.S. Gov't, P.H.S.

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J Griffith, A Hochschild, M Ptashne. DNA loops induced by cooperative binding of lambda repressor.. https://doi.org/10.1038/322750a0

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