what are histone & non histone proteins ?
Histones are positively charged basic proteins (positive and basic due to presence of positive and basic amino acid residues, lysine and arginine). DNA (negatively charged) winds around histone octamer (positively charged) to form nucleosome.
Non-histone chromosomal proteins are additional set of proteins required for packaging of chromatin at higher level (chromatin fibres and chromosomes). For example - Protein A24.