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.

Original languageEnglish
Pages (from-to)178-194
Number of pages17
JournalJournal of Molecular Biology
Issue number2
StatePublished - Aug 15 1997


  • DNA-protein interaction
  • DNA-protein specificity
  • Information content
  • Mnt protein
  • Quantitative DNA sequencing


Dive into the research topics of 'Quantitative specificity of the Mnt repressor'. Together they form a unique fingerprint.

Cite this