The electrostatic interactions that occur between histones and DNA provide the energy needed to fold DNA into a compact shape, allowing histones to form a very tight bond. Histones are positively charged proteins, while DNA exhibits a negative charge due to its phosphate composition, according to Nature Education.
Nature Education describes the interaction between histones and DNA using the analogy of winding a garden hose. DNA wraps around eight histone proteins to form a single nucleosome, which then folds to produce a 30-nanometer fiber. The publication estimates that each human being has about 100 trillion meters of DNA inside the body, making an effective biological coiling mechanism important for maintaining reasonable cell size. Histones are the proteins responsible for this coiling mechanism, and their powerful electrostatic bond provides considerable energy, keeping the coil tight.
Histones also play an important role in determining the regulation of gene expression, claims Science Daily. Researchers have found a link between histone crosstalk, histone modification through methylation, and gene expression. These findings suggest that the tight bond between histones and DNA is more than a convenient biological process for storing DNA; they indicate that histones play an integral part in the expression of genetic attributes and traits described by DNA.