Monday, February 23, 2015

The Many Images of Topoisomerase II

This image is just a residue of topoisomerase II (PDB 1BJT). This is the core that binds to and cleaves the DNA (residues 409-1201). The spaces where DNA fits are apparent in this structure. Because this is only a residue, this is all one chain.

This image is the same topoisomerase residue as above (PDB 1BJT), but here you can see the helices and sheets that make up this residue. Again, this is all one chain and the color represents that.

In this image (PDB 2RGR) we can see the same topoisomerase II residue as before, but now it is bound to the helical DNA (shown in pink and blue). Topoisomerase II helps relax super-coiling and repairs knots in the DNA by cutting through both strands and releasing tension.

This next image (PDB 2RGR) shows the residue that binds to the DNA and the DNA molecule as well. When the colors are sorted by chain, you can see the doubled-stranded helical DNA in pink and blue and the chain in green is the topoisomerase II.

In this final image (PDB 1BJT), we can see the topoisomerase II residue not bound to the DNA.


  1. Looks like this will be an interesting protein!

  2. Very interesting protein! Definitely a protein worth learning more about. Very cool that it has such a massive and important function in our body, i suppose without it, we would all probably have a bunch of problems with our bodies haha. You do a great job incorporating the important reactions it catalyzes, but explain the second figure in your latest post, it looks great, but I am unsure what is happening in it. And explain some more of the defects that mutations in this causes in humans, I think that would be really interesting. Otherwise, great job!