Tryptophan Research Paper

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Tryptophan is an essential amino acid, which is either synthesized or injested from the environment in bacterial cells.The production of tryptophan is an energy consuming process. So bacteria need to ensure that only when the concentration of tryptophan is low inside cell , it has to produce tryptophan. The trp operon is a repressible system that regulates the biosynthesis of tryptophan. The gene for the repressor is located not near to the promoter,but in a different location.It has an operator which is embedded in the promoter,a leader sequence(trpL) and 5 structural genes(trpE,trpD,trpC,trpB,trpA). Each gene encodes for proteins in the trp synthesis pathway. When the concentration of tryptophan is low there is no blockage for the transcription and tryptophan is produced.…show more content…
The mechanism of attenuation in trp operon The process of controlling transcription termination by the rate of translation of the attenuator is termed as attenuation. In bacterial cells transcription and translation are coupled. The leader sequence (trpL) controls the operon through attenuation. The leader sequence has 4 main regions with some kind of palindromic sequence. When the amount of tryptophan is low the translation of domain1 (requires trp) slows down.The domains 2& 3 pairs which allows the continued transcription, resulting in the biosynthesis of tryptophan. At high concentrations of tryptphan , ribosome quickly moves through domain1 and associates with 2.This enables the strong pairing between domains 3&4.This pairing creates a stem and loop structure in the mRNA . This terminates transcription and the structural genes required for the tryptophan synthesis are not

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