title: Crystal structure of the met repressor-operator complex at 2.8 A resolution reveals DNA recognition by beta-strands.
abstract: The crystal structure of the met repressor-operator complex shows two dimeric repressor molecules bound to adjacent sites 8 base pairs apart on an 18-base-pair DNA fragment. Sequence specificity is achieved by insertion of double-stranded antiparallel protein beta-ribbons into the major groove of B-form DNA, with direct hydrogen-bonding between amino-acid side chains and the base pairs. The repressor also recognizes sequence-dependent distortion or flexibility of the operator phosphate backbone, conferring specificity even for inaccessible base pairs.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Leeds, UK.
authors.forename: W S
authors.initials: WS
authors.lastname: Somers
authors.forename: S E
authors.initials: SE
authors.lastname: Phillips
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D001483:Base Sequence; D003461:Crystallography; D004269:DNA, Bacterial / Q000737:chemistry; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D005809:Genes, Regulator; D008715:Methionine / Q000096:biosynthesis*; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D009875:Operator Regions, Genetic / Q000235:genetics*; D012097:Repressor Proteins / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D012097:Repressor Proteins; C060486:methionine repressor protein, Bacteria; C489220:methionine repressor protein, E coli; D008715:Methionine