Question

One form of chromatin modification is acetylation, which is known to occur on positively charged histone tail amino acids, thus neutralizing the charge. Based on your understanding of chromatin packaging, we would expect this to (INCREASE/DECREASE/NOT IMPACT) DNA compaction. Which of the following statements best explains your answer?
A. The tails do not interact with the DNA.
B. The tails would now be unable to link together two nucleosomes.
C. The tails would now more tightly interact.

Answer 1

Answer:

A. The tails do not interact with the DNA

Explanation:

The acetylation refers to the transfer of the acetyl group from Acetyl-CoA to the N-terminal of the histone protein.

Lysine residues (positively charged amino acid) are present at the end of the N-terminal of the histone protein which is neutralized by the acetyl group.

This loses the compaction between the positively charged histone and the negatively charged DNA and the DNA becomes more relaxed. This relaxed state allows the transcription factors to easily bind the DNA and therefore the DNA becomes transcriptionally active.

Thus, Option-A is correct