title: Structure and function of Escherichia coli met repressor: similarities and contrasts with trp repressor.
abstract: Transcription of genes encoding enzymes for the biosynthesis of methionine and trytophan in Escherichia coli is regulated by the ligand-activated met and trp repressors. X-ray crystallographic studies show how these two small proteins, although similar in size and function, have totally different three-dimensional structures and specifically recognize their respective DNA operator sequences in different ways. A common feature is that both repressors bind as cooperative arrays to tandem repeats of 8 base-pair 'Met' or 'Trp boxes' respectively, and the consensus sequences share the rare tetranucleotide CTAG. A series of structural and functional studies have shown how the two repressors discriminate between their operators, using a combination of direct contacts between side chains and bases, and indirect sensing of conformational properties of the DNA.
authors: Department of Biochemistry and Molecular Biology, University of Leeds, U.K.
authors: S E
authors: SE
authors: Phillips
authors: P G
authors: PG
authors: Stockley
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D001483:Base Sequence; D016384:Consensus Sequence; D018360:Crystallography, X-Ray; D004269:DNA, Bacterial / Q000737:chemistry / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins; D008715:Methionine / Q000096:biosynthesis; D008961:Models, Structural; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D017433:Protein Structure, Secondary; D012097:Repressor Proteins / Q000737:chemistry* / Q000378:metabolism*; D012689:Sequence Homology, Nucleic Acid; D012984:Software; D014158:Transcription, Genetic; D014364:Tryptophan / Q000096:biosynthesis
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D012097:Repressor Proteins; C027190:TRPR protein, E coli; C060486:methionine repressor protein, Bacteria; C489220:methionine repressor protein, E coli; D014364:Tryptophan; D008715:Methionine