Question

Histone octamer contains

• A. Eight types of histones
• B. Eight histones of four different types
• C. Five histones
• D. Six types of histones

Answer 1

The correct option is B Eight histones of four different types

In eukaryotes, DNA organization is much more complex and is carried out by a set of positively charged basic proteins called histones. Histones are rich in the basic amino acids residues lysines and arginines with charged side chains. There are five types of histone proteins i.e., $H_1$, $H_{2}A$, $H_{2}B$, $H_3$ and $H_4$. Four of them occur in pairs to produce histone octamer or nu-body. A histone octamer contains eight proteins of four different types i.e., two copies of each $H_{2}A$, $H_{2}B$, $H_3$ and $H_4$. The negatively charged DNA is wrapped around the positively charged histone octamer to form a structure called nucleosome.