We have reconstituted Bacillus subtilis trp attenuation in vitro. Purification of the mtrB gene product (TRAP) to near homogeneity allowed us to demonstrate that addition of this protein plus L-tryptophan to template, RNA polymerase, and nucleoside triphosphates caused transcription termination in the trpEDCFBA leader region. TRAP acts by binding to the nascent transcript and preventing formation of an RNA antiterminator structure, thereby allowing terminator formation and transcription termination. Oligonucleotides complementary to segments of the antiterminator were used to demonstrate that formation of this RNA hairpin was responsible for transcription read-through. TRAP was found to be a 60-kDa multimeric protein composed of identical 6- to 8-kDa subunits, and its elution profile on a chromatographic column did not change in the presence of tryptophan.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - 1993|
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