The trp RNA-binding attenuation protein regulates TrpG synthesis by binding to the trpG ribosome binding site of Bacillus subtilis.
The trpG gene of Bacillus subtilis encodes a glutamine amidotransferase subunit which is involved in the biosynthesis of L-tryptophan and folic acid. The trp RNA-binding attenuation protein (TRAP) is involved in controlling expression of trpG at the level of translation in response to changes in the intracellular concentration of tryptophan. We performed in vitro experiments using purified TRAP to elucidate the mechanism of TRAP-dependent trpG regulation. A TRAP-trpG RNA footprint analysis showed that tryptophan-activated TRAP interacts with one UAG, one AAG, and seven GAG repeats present in the trpG transcript. Results from ribosome and TRAP toeprint experiments indicated that the ribosome and TRAP binding sites overlap. Experiments with a B. subtilis cell-free translation system demonstrated that TRAP inhibits TrpG synthesis. Thus, TRAP regulates translation of trpG by blocking ribosome access to the trpG ribosome binding site. Our results are consistent with a model in which each tryptophan-activated TRAP subunit interacts with one trinucleotide repeat in an RNA target, thereby wrapping the transcript around the periphery of the TRAP complex.
Du
H
H
Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park 16802, USA.
Tarpey
R
R
Babitzke
P
P
D000878:Anthranilate Synthase; D001412:Bacillus subtilis / Q000235:genetics*; D001426:Bacterial Proteins; D001483:Base Sequence; D001665:Binding Sites; D002474:Cell-Free System; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D008969:Molecular Sequence Data; D019884:Nitrogenous Group Transferases; D009690:Nucleic Acid Conformation; D012329:RNA, Bacterial / Q000737:chemistry / Q000378:metabolism; D012333:RNA, Messenger / Q000737:chemistry / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism*; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics; D012270:Ribosomes / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D014166:Transferases / Q000096:biosynthesis / Q000235:genetics*; D014364:Tryptophan / Q000502:physiology
D001426:Bacterial Proteins; C079092:MtrB protein, Bacteria; D012329:RNA, Bacterial; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D014157:Transcription Factors; D014364:Tryptophan; D014166:Transferases; D019884:Nitrogenous Group Transferases; D000878:Anthranilate Synthase; C020655:anthranilate synthase, glutamine amidotransferase subunit