1 / 8

Gene Expression Regulation: trp Operon

Gene Expression Regulation: trp Operon. trp Operon. trp – tr y p tophan The genes of the trp operon are used to make the amino acid tryptophan. It is turned off when enough tryptophan is in the cell. Tryptophan is the effector molecule. trp Operon.

cinnamon-mitchell
Télécharger la présentation

Gene Expression Regulation: trp Operon

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Gene Expression Regulation:trpOperon

  2. trp Operon • trp – tryptophan The genes of the trp operon are used to make the amino acid tryptophan. It is turned off when enough tryptophan is in the cell. Tryptophan is the effector molecule.

  3. trp Operon Operon codes for 5 genes – found in E. coli Five polypeptides combine to make three enzymes. • each enzyme participates in a step to make tryptophan

  4. Repressor Protein repressor protein (trpR) • binds to operator when tryptophan is present • prevents RNA polymerase from transcribing genes when bound to operator • transcribed as a different gene from trp operon When do you want the repressor to bind / not bind to the trp operon?

  5. When tryptophan needs to be made: • enzymes are required to make tryptophan • repressor is NOT bound to operator • transcription can proceed

  6. When cell has enough tryptophan: • tryptophan binds to repressor • repressor can now bind operator to prevent transcription

  7. Effector Molecule Since tryptophan is the molecule that determines when the operon is turned on or off, it is known as an effector molecule. corepressor – effector molecule that binds repressor protein to cause it to bind to the operator

More Related