title: A LexA mutant repressor with a relaxed inter-domain linker.
abstract: The LexA protein is part of a large family of prokaryotic transcriptional repressors that contain an amino-terminal DNA binding domain and a carboxy-terminal dimerization domain. These domains are separated by a linker or hinge region, which is generally considered to be rather flexible and unconstrained. So far, no structure of any of the full-length repressors is available. Here we show that a mutant LexA repressor harboring several point mutations in the hinge region gets sensitive to trypsin and Glu-C cleavage over a segment of at least 20 amino acids, whereas the LexA wild-type hinge region is resistant to these proteases. These data are not compatible with the hypothesis of an fully flexible and/or unstructured inter-domain linker and suggest that the LexA hinge region is, in fact, constrained by contacts with the carboxy-terminal domain and/or a fairly stable local structure of the linker region.
authors.affiliation: Institut de Biologie Moléculaire et Cellulaire, UPR 9002 du CNRS, Strasbourg, France.
authors.forename: P
authors.initials: P
authors.lastname: Oertel-Buchheit
authors.forename: J
authors.initials: J
authors.lastname: Reinbolt
authors.forename: M
authors.initials: M
authors.lastname: John
authors.forename: M
authors.initials: M
authors.lastname: Granger-Schnarr
authors.forename: M
authors.initials: M
authors.lastname: Schnarr
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006868:Hydrolysis; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009875:Operator Regions, Genetic; D017433:Protein Structure, Secondary; D012097:Repressor Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D012697:Serine Endopeptidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D014357:Trypsin / Q000378:metabolism; D000099160:LexA Repressor Protein
chemical_list: D001426:Bacterial Proteins; D012097:Repressor Proteins; D012697:Serine Endopeptidases; D014357:Trypsin; D000099160:LexA Repressor Protein; C028344:glutamyl endopeptidase