Question

In what way is $\sigma^{54}$ defective?

    In what way is $\sigma^{54}$ defective?

Molecular Biology

Molecular Biology

Robert F. Weaver 5th Edition

Chapter 9, Problem 14

Instant Answer

Solved by Expert Jennifer Stoner

02/07/2023

Step 1

A permutation is considered defective if it does not have a full cycle structure, meaning it cannot be expressed as a single cycle that includes all elements. Show more…

Show all steps

lock

Thanks for your feedback!

In what way is $\sigma^{54}$ defective?

Play audio

Feedback

Powered by NumerAI

Jennifer Stoner and 59 other educators are ready to help you.

Ask a new question

Labs

Want to see this concept in action?

NEW

Explore this concept interactively to see how it behaves as you change inputs.

View Labs

Key Concepts

Sigma Factor Function

Sigma factors are essential proteins that bind to RNA polymerase to direct it to specific promoter sequences, thereby initiating transcription. While most sigma factors enable RNA polymerase to transition rapidly from a closed to an open complex at the promoter, sigma54 is unusual in that it does not by itself promote this isomerization.

Promoter Complex Formation

In transcription initiation, forming an open complex is critical as it involves melting the DNA double helix to expose the template strand for RNA synthesis. Sigma54 is characterized by its tendency to form a stable closed complex with the DNA, meaning that it is defective at spontaneously promoting the necessary DNA melting for transcription to begin.

Activator-Dependent Mechanism

Due to its inherent inability to induce promoter melting on its own, sigma54-dependent transcription requires the action of specialized activator proteins. These activators, often ATPases, use energy from ATP hydrolysis to remodel the RNA polymerase-sigma54-promoter complex into an open complex, thereby overcoming the defect in sigma54.

Recommended Videos

Transcript

Ace is your personal tutor. It breaks down any question with clear steps so you can learn.

Start Using Ace

Continue solving this problem

Create a free account to:

View full step-by-step solution
Ask follow-up questions with Ace AI
Save progress and study later