Question

What is wrong with the mechanism shown in this movie? ?v=hvNJ3yWZQbE

a. ATP hydrolysis is not required for ubiquitin to bind to E1
b. ubiquitinated proteins do not bind to the lid of the proteasome
c. the proteasome does not open and close like a recycle bin
d. the proteasome does not shred the protein into tiny bits

Answer 1

The mechanism shown in the movie is incorrect because b. ubiquitinated proteins do not bind to the lid of the proteasome.

Step-by-step explanation:

In the ubiquitin-proteasome system, ubiquitinated proteins are recognized and targeted for degradation by the 26S proteasome. However, in the provided options, the incorrect statement is that ubiquitinated proteins bind to the lid of the proteasome. In reality, ubiquitinated proteins bind to the 19S regulatory particle, which acts as a cap on both ends of the proteasome.

The 19S regulatory particle recognizes ubiquitinated proteins, unfolds them, and translocates them into the 20S core particle, where degradation occurs. The proteasome does not have a lid that binds to ubiquitinated proteins. The mechanism is essential for maintaining cellular homeostasis by selectively degrading proteins involved in various cellular processes.

Option B is the answer.