What is a histone made of?

Histones are primarily made of basic, positively charged amino acid residues like arginine and lysine. The positive charges allow them to interact with the negatively charged DNA through electrostatic interactions. Neutralizing charges in the DNA permits it to become even more tightly packed. 

A histone octamer is a complex of 8 positively charged histone particles that assist in DNA packaging. They are located at the center of the nucleosome core particle. Histones make up 2 copies of the 4 core histone proteins (H2A, H2B, H3 and H4). Negatively charged DNA surrounds the positively charged histone octamer to create nucleosomes. Each histone has a C-terminal histone-fold and an N-terminal tail, which both play a role in interactions with DNA through hydrogen bonding. This bonding holds the DNA and histone octamer loosely to be able to rearrange.