Transcriptional regulation of trp operon by tryptophan involves binding of tryptophan to
1
the repressor protein and inhibition of transcription by its interaction with the operator region.
2
RNA polymerase and inhibition of transcription.
3
the repressor protein leading to structural changes and its degradation by proteases.
4
the repressor protein leading to its interaction with the sigma subunit and inhibition of transcription.