Which of the following statements are correct with reference to packaging of DNA helix ?
A. Histones are organized to form a unit of eight molecules called histone octamer.
B. Histones are negatively charged basic proteins.
C. Histones are rich in the basic amino acid residues – lysine and arginine.
D. The positively charged DNA is wrapped around the histone octamer to form nucleosome.
E. The packaging of chromatin at higher levels requires an additional set of proteins called non-histone chromosomal proteins.
Choose the correct answer from the options given below :

(A) A, C and E only
Statement A is correct. Histones are organized to form a unit of eight molecules called a histone octamer.
Statement B is incorrect. Histones are positively charged, basic proteins, not negatively charged.
Statement C is correct. Histones are rich in the basic amino acid residues lysine and arginine, which carry positive charges in their side chains.
Statement D is incorrect. DNA is a negatively charged molecule (due to phosphate groups), which is wrapped around the positively charged histone octamer to form a nucleosome.
Statement E is correct. The packaging of chromatin at higher levels requires an additional set of proteins that are collectively referred to as Non-Histone Chromosomal (NHC) proteins.
Therefore, only statements A, C, and E are correct.