title: Structural features of L-tryptophan required for activation of TRAP, the trp RNA-binding attenuation protein of Bacillus subtilis.
abstract: A filter binding assay was used to determine the structural features of L-tryptophan required for activation of TRAP, the trp RNA-binding attenuation protein of Bacillus subtilis. We examined the ability of L-tryptophan and 26 of its analogs to activate TRAP. Our findings show that TRAP activation by L-tryptophan is highly cooperative. We also observed that TRAP activation is stereospecific; D-tryptophan did not activate. Our results further indicate that the alpha-amino group and the carbonyl moiety of the alpha-carboxyl group of the ligand are required for TRAP activation and that the heterocyclic amino nitrogen of L-tryptophan greatly enhances TRAP activation. We also found that changes at several positions of the indole ring of L-tryptophan resulted in reduced TRAP activation. In addition, indole and 5-methylindole were shown to be effective competitors of L-tryptophan activation of TRAP.
authors.affiliation: Department of Biological Sciences, Stanford University, California 94305, USA.
authors.forename: P
authors.initials: P
authors.lastname: Babitzke
authors.forename: C
authors.initials: C
authors.lastname: Yanofsky
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D001667:Binding, Competitive; D015964:Gene Expression Regulation, Bacterial; D007211:Indoles / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism*; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D014157:Transcription Factors / Q000378:metabolism*; D014364:Tryptophan / Q000031:analogs & derivatives / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D007211:Indoles; C079092:MtrB protein, Bacteria; D016601:RNA-Binding Proteins; D014157:Transcription Factors; C030374:indole; D014364:Tryptophan; C093726:5-methylindole