Question

Inclusion bodies contain ________.

• A. \( \text{DNA} \)
• B. \( \text{Lipids} \)
• C. \( \text{Active proteins} \)
• D. \( \text{Misfolded proteins} \)

Hint:

Inclusion bodies are actually a "blessing and a curse"; they are easy to isolate by centrifugation but hard to refold into active forms.

Answer 1

The Correct Option is D

Concept: Inclusion bodies are nuclear or cytoplasmic aggregates of stable substances, usually proteins.
• They often form in bacteria during the high-level expression of recombinant proteins.
• These aggregates represent a significant challenge in downstream bioprocessing.

Step 1: Mechanism of Formation.
When a cell is forced to produce massive amounts of a foreign protein, the protein often fails to fold correctly. These misfolded polypeptide chains expose hydrophobic regions that would normally be buried.

Step 2: Aggregation into Inclusion Bodies.
To prevent these "sticky" proteins from interfering with cellular machinery, the cell clusters them together. These dense, insoluble aggregates are called inclusion bodies. To regain function, these proteins must be dissolved with denaturants and carefully refolded. Final Answer: Inclusion bodies are primarily composed of Misfolded proteins.