Quantitative specificity of the Mnt repressor.
The Mnt protein of Salmonella phage P22 binds site-specifically to its operator. To better understand this binding we used dideoxy DNA sequencing in a quantitative manner to determine the relative binding constants, and hence the relative free energies, of wild-type Mnt protein to a substantial number of variants of its operator. These measurements were supported by experiments which used the SELEX procedure to generate a set of operators from an initially randomized population. In the Discussion we show that the present model of Mnt protein/operator binding, due to Sauer and co-workers, along with the assumption of an independent contribution of each position in the operator to the total binding, provides a reasonably accurate description of the system. We also discuss the use of information content as a measure of DNA-protein binding specificity with the Mnt protein/operator system serving as an example and show again that the assumption of independence supports the current view of this case of site-specific binding.
Fields
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Department of Molecular Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309-0347, USA.
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Al-Uzri
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Stormo
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D017100:Bacteriophage P22 / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D016384:Consensus Sequence; D004247:DNA / Q000737:chemistry* / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D007700:Kinetics; D008024:Ligands; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000737:chemistry* / Q000378:metabolism*; D012097:Repressor Proteins / Q000378:metabolism*; D012475:Salmonella / Q000821:virology; D016415:Sequence Alignment; D013379:Substrate Specificity; D013698:Templates, Genetic; D013816:Thermodynamics; D014764:Viral Proteins / Q000378:metabolism*; D054334:Viral Regulatory and Accessory Proteins
D004268:DNA-Binding Proteins; D008024:Ligands; D009838:Oligodeoxyribonucleotides; D012097:Repressor Proteins; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; C016649:phage repressor proteins; D004247:DNA