​Which one of the following types of interactions will be predominantly contributing to the stability of a nucleosome?​

Correct option is D

Explanation:

• (1): Incorrect. While hydrogen bonds do form between DNA base pairs, these interactions do not significantly contribute to the stability of a nucleosome. The serine and threonine residues in histones are involved in modifications (such as phosphorylation) but do not directly stabilize the nucleosome.

• (2): Incorrect. Van der Waals interactions between DNA base pairs and hydrophobic residues of histones do occur, but they do not play a dominant role in stabilizing the nucleosome. The major stabilizing interactions are more electrostatic in nature.

• (3): Incorrect. Hydrogen bonds between the DNA phosphate backbone and the main chain atoms of histones also occur, but they are not the primary contributors to nucleosome stability. These interactions are weaker compared to the electrostatic forces involved.

• (4): Correct. The primary contributor to nucleosome stability is electrostatic interactions between the DNA phosphate backbone (which is negatively charged) and the lysine residues of histones (which are positively charged). This creates strong ionic interactions, helping to hold the DNA wrapped around the histone core tightly.

Information Booster:

1. Nucleosome stability is predominantly driven by electrostatic interactions between negatively charged DNA and the positively charged histone proteins.

2. The lysine residues on histones play a key role in the stabilization of the nucleosome by forming electrostatic bonds with the DNA phosphate backbone.

3. While hydrogen bonds and van der Waals interactions contribute to nucleosome formation, they are not as significant in maintaining the overall stability as electrostatic interactions.

4. Histone modifications (like acetylation, methylation, phosphorylation) can alter the electrostatic interactions and affect nucleosome stability and chromatin structure.