title: TrmB, a sugar-specific transcriptional regulator of the trehalose/maltose ABC transporter from the hyperthermophilic archaeon Thermococcus litoralis.
abstract: We report the characterization of TrmB, a protein of 38,800 apparent molecular weight, that is involved in the maltose-specific regulation of a gene cluster in Thermococcus litoralis, malE malF malG orf trmB malK, encoding a binding protein-dependent ABC transporter for trehalose and maltose. TrmB binds maltose and trehalose half-maximally at 20 microm and 0.5 mm sugar concentration, respectively. Binding of maltose but not of trehalose showed indications of sigmoidality and quenched the intrinsic tryptophan fluorescence by 15%, indicating a conformational change on maltose binding. TrmB causes a shift in electrophoretic mobility of DNA fragments harboring the promoter and upstream regulatory motif identified by footprinting. Band shifting by TrmB can be prevented by maltose. In vitro transcription assays with purified components from Pyrococcus furiosus have been established to show pmalE promoter-dependent transcription at 80 degrees C. TrmB specifically inhibits transcription, and this inhibition is counteracted by maltose and trehalose. These data characterize TrmB as a maltose-specific repressor for the trehalose/maltose transport operon of Thermococcus litoralis.
authors.affiliation: Department of Biology, University of Konstanz, Germany.
authors.forename: Sung-Jae
authors.initials: SJ
authors.lastname: Lee
authors.forename: Afra
authors.initials: A
authors.lastname: Engelmann
authors.forename: Reinhold
authors.initials: R
authors.lastname: Horlacher
authors.forename: Qiuhao
authors.initials: Q
authors.lastname: Qu
authors.forename: Gudrun
authors.initials: G
authors.lastname: Vierke
authors.forename: Carina
authors.initials: C
authors.lastname: Hebbeln
authors.forename: Michael
authors.initials: M
authors.lastname: Thomm
authors.forename: Winfried
authors.initials: W
authors.lastname: Boos
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics*; D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000302:isolation & purification / Q000502:physiology*; D001483:Base Sequence; D001665:Binding Sites; D008320:Maltose / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D005810:Multigene Family; D009876:Operon; D012097:Repressor Proteins / Q000302:isolation & purification / Q000502:physiology*; D019712:Thermococcus / Q000737:chemistry / Q000235:genetics*; D014158:Transcription, Genetic; D014199:Trehalose / Q000378:metabolism*
chemical_list: D018528:ATP-Binding Cassette Transporters; D019843:Archaeal Proteins; D012097:Repressor Proteins; D008320:Maltose; D014199:Trehalose