3D Structure of Nucleosome

3D Structure of Nucleosome

CPK Color Scheme

On this page, you can see a nucleosome from a frog, but it looks like a jumbled mess the way it is depected intially. You can click and drag to explore the shape before clicking on the buttons below.

To make sense of this structure, the first thing you need to do is get rid of the proteins and visualize only the 147 bp of DNA that is wrapped around the histone proteins of the nucleosome. As the coiled DNA rotates, try to notice that the DNA forms two coils around the space that appears empty for now. The final view shows the two cut ends of the DNA that normally would continue on to the next nucleosomes on the chromosome.

Click this button to make the DNA go away and visualize the eight histone proteins that forme the protein core around which the DNA is wrapped. Note that there are two yellow proteins (called H3), two pink proteins (called H4), two green proteins (called H2A) and two orange proteins (called H2B). All four types of proteins have tails that extend out and can be covalently modified which can alter gene activity.

Turn the proteins into more solid objects and put the DNA around the histone proteins. After the nucleosome stops moving, the proteins will all turn to white so you can focus on the overall structure of the protein complex.


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