Probing met repressor-operator recognition in solution.

Y Y He; T McNally; I Manfield; O Navratil; I G Old; S E Phillips; I Saint-Girons; P G Stockley

doi:10.1038/359431a0

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PubMed · 1406957

Probing met repressor-operator recognition in solution.

Y Y He·T McNally·I Manfield·O Navratil·I G Old·S E Phillips·I Saint-Girons·P G Stockley

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Abstract

The three-dimensional crystal structure of the Escherichia coli methionine repressor, MetJ, complexed with a DNA operator fragment is described in an accompanying article. The complex exhibits several novel features of DNA-protein interaction. DNA sequence recognition is achieved largely by hydrogen-bond contacts between the bases and amino-acid side chains located on a beta-ribbon, a mode of recognition previously hypothesized on the basis of modelling of idealized beta-strands and DNA, and mutagenesis of the Salmonella phage P22 repressors Arc and Mnt. The complex comprises a pair of MetJ repressor dimers which bind to adjacent met-box sites on the DNA, and contact each other by means of a pair of antiparallel alpha-helices. Here we assess the importance of these contacts, and also of contacts that would be made between the C-helices of the protein and DNA in a previous model of the complex, by studying mutations aimed at disrupting them. The role of the carboxy-terminal helix face in operator binding was unclear, but we demonstrate that recognition of operator sequences occurs through side chains in the beta-strand motif and that dimer-dimer interactions are required for effective repression.

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Base Sequence Cloning, Molecular DNA Dose-Response Relationship, Drug Escherichia coli Gene Expression Regulation Genes, Regulator Hydrogen Bonding In Vitro Techniques Methionine Molecular Conformation Molecular Sequence Data Mutagenesis, Site-Directed Operator Regions, Genetic Potassium Chloride beta-Galactosidase Journal Article Research Support, Non-U.S. Gov't Comment

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Y Y He, T McNally, I Manfield, O Navratil, I G Old, S E Phillips, I Saint-Girons, P G Stockley. 1992-10-01. Probing met repressor-operator recognition in solution.. https://doi.org/10.1038/359431a0

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