Of the side-chain modifications listed, which ones will decrease the positive charge on a histone? A. lysine methylation only B. lysine acetylation only C. serine phosphorylation only D. both lysine methylation and acetylation E. both lysine acetylation and serine phosphorylation Solution Lysine acetylation and lysine methylation are important side-chain modifications in histone. Lysine acetylation reduces the positive charge on the side chain rather it renders the chain neutral. Therefore, option C and A are elimination. In case of lysine methylation also, positive charge decreases. Therefore answer will be D. .