Nucleosome Components

Histone Octamer

DNA Strands

Learning Objectives
  1. To understand how the eight histones form the core of the nucleosome.
  2. To understand how the DNA makes nearly two supercoils around the histone core.

Activity Instructions

Explore the three-dimensional structure of a nucleosome. The 3D structure of the nucleosome core particle is shown in the window on the left. Click the names of the individual proteins or DNA strands on the right to color them individually. Click and drag to rotate the molecule; hover the mouse over an atom to identify it.

  1. What is the predominant secondary structure in each of the four histone proteins shown?
  2. How many superhelical turns of DNA are shown in the 3D structure?
  3. The eight protein strands in the nucleosome core associate as four pairs of dimers. What are those four pairs?