Question

Which of the following is NOT an effect of histone acetylation?

a. the positive charges on lysines are neuralized
b. conversion of the beads on a string to the 30 nM fiber
c. DNA binding to the nucleosomes is weakened
d. recruitment of SWI/SNF
e. disruption of electrostatic interactions between neighboring nucleosomes

Answer 1

b. conversion of the beads on a string to the 30 nM fiber

Step-by-step explanation:

Histone acetylation process adds an acetyl group to lysine amino acid in histone protein. Lysine is usually positively charged and thus is able to make strong bond with negatively charged DNA molecule. When acetyl group is added to lysine, its positive charge is removed. The bond between histone and DNA weakens and the whole structure becomes more open, loose and transcriptionally active.

Beads on a string is formed by wrapping of DNA around histone proteins. This structure further condenses into 30nm fiber leading to more compact and tightly packed chromatin structure. Since histone acetylation loosens up the chromatin, this process does not take place here.