<prompt> Histone proteins are rich in which of the following amino acids?Histidine and lysineLysine and ArginineArginine and HistidineHistidine and Valine  <response>: Histone proteins: Rich in positively charged amino acids, lysine and arginine. Carboxyl terminal 23rd of histone molecules are hydrophobic, Amino terminal 13rd are paicularly rich in basic amino acids. These amino terminal end protrude out of the octamer and is known as histone tail. Amino acids of histone tail undergo post-translational modifications. 