Trp Operon - Attenuation - Part I Flashcards
What does the process of Attenuation accomplish?
Prevents the completion of transcription
Describe how attenuation is only possibel in prokaryotic cells
As transcriptiona nd translation occur in same location in prokaryotic cells
Where is the Leader found in the trp Operon?
Between operator and first gene of operon
Where is the attenuator region found?
It is part of leader sequence, it follows the begining of the leader
What does the Leader sequence produce?
A short mRNA that translates to a short polypeptide
How many domains does the Leader have?
4 domains
Describe the role of Domain 1 in Leader
- Encodes a short polypeptide known as Leader sequence.
- Domain 1 includes 2 trp codons
Describe the role of domains 2-4 in Leader
- This is the attenuator sequence
- Does not encode a polypeptide (no translation)
- When transcribed, mRNA has self complementary sections
- These sections can form various hairpin structures/loops
What are the two hairpin loops that the attenuator region can form?
- Anti-terminator hairpin loop
- Terminator hairpin loop
Anti-terminator loops is formed by which domains interacting?
Self-complementary regions of Domain 2 and 3 interact
Terminator loop is formed by which domains interacting?
Self-complementary regions of Domains 3 and 4
Explain why both terminator and anti-terminator hairpin loops cannot exist at same time
- Both involve interaction of Doamin 3
- Thus, domain 3 can only interact to form 1 hairpin loop at a time
