Virtuelle (Nano) Welten PDB Molecule of the Month 94: Superoxide Dismutase

Exploring the Structure

Cu/Zn superoxide dismutase (PDB entry 2sod) is a very efficient enzyme. Researchers have determined that one out of every ten collisions between superoxide and the enzyme will lead to a reaction. This is far more than expected, since the active site covers only a small portion of the enzyme surface, and we might expect that most collisions would occur somewhere else on the surface. The shape and characteristics of the active site, however, may give some hints to this efficiency. The active site is funnel shaped, with the copper and zinc (colored green here) at the base of the funnel. The strong positive charge of the metal ions, along with two nearby positively-charged amino acids (colored blue here), serve to draw the negatively-charged superoxide (red) into the funnel.

This picture was created with RasMol. You can create similar pictures by clicking on the accession code here and picking one of the options under Images and Visualization. To see some of the scientific papers that I used when writing this Molecule of the Month, click here. Also available are related entries in the PDB as determined by a keyword search on September 26, 2007 for 'Superoxide Dismutase'.