Why do histones bind tightly to DNA?
1 Answer
because they have opposite charges.
Explanation:
Histones are proteins that pack the DNA into manageable packages. These histones contain many positively charged amino acids (lysine, arginine) making the proteins overall positively charged .
DNA is negatively charged due to the phosphate groups in the backbone of DNA. Since opposite charges attract, DNA can bind very well to the histones.
Hydrogen bonding bewteen hydroxyl amino acids in the histones and the backbone of DNA also contribute to the binding ability.
The image shows what is called a nucleosome consisting of a core with 8 histones (positive charge) and part of the DNA (negative charge) wrapped around it. The histones also have long tails these play an important role in regulation but also contribute to stability of the nucleosomes.
