title: An operator binding-negative mutation of Xyl repressor from Bacillus subtilis is trans dominant in Bacillus megaterium.
abstract: We have selected a Bacillus subtilis 168-borne xylR Ser to Leu mutation at position 41 of the encoded amino acid sequence showing a constitutive expression phenotype for the xyl operon. When cloned on a multi-copy plasmid in a B. megaterium strain harbouring a single-copy xylA-lacZ fusion it leads to derepression of beta-galactosidase expression. Thus, it is trans dominant over the endogenous xylR, indicating that Xyl repressor functions as a multimer. This result also supports the assumption that the mutation is in a putative alpha-helix-turn-alpha-helix operator binding motif of Xyl repressor.
authors.affiliation: Lehrstuhl für Mikrobiologie, Friedrich-Alexander Universität Erlangen-Nürnberg, FRG.
authors.forename: C
authors.initials: C
authors.lastname: Kauder
authors.forename: R
authors.initials: R
authors.lastname: Allmansberger
authors.forename: D
authors.initials: D
authors.lastname: Gärtner
authors.forename: D
authors.initials: D
authors.lastname: Schmiedel
authors.forename: W
authors.initials: W
authors.lastname: Hillen
mesh_terms: D000595:Amino Acid Sequence; D001410:Bacillus megaterium / Q000235:genetics*; D001412:Bacillus subtilis / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D015870:Gene Expression; D005799:Genes, Dominant; D008969:Molecular Sequence Data; D009154:Mutation; D009875:Operator Regions, Genetic; D010957:Plasmids / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics*; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D012097:Repressor Proteins; C074580:Xyl repressor protein, Bacillus subtilis