Virtuelle (Nano) Welten: PDB Molecule of the Month 1: Myoglobin

A Closer Look

John Kendrew's original myoglobin structure is available with the accession code 1mbn. The structure contains one protein chain, a heme group (with a water molecule bound to the iron), and a sulfate ion. Ignore the sulfate ion -- it's merely along for the ride. There are several things to look for in this structure. The protein chain is composed of spring-shaped alpha-helices, linked together by short loops. The chain surrounds the flat heme group. At the center, you can see the iron atom, surrounded by four blue nitrogen atoms. This structure file doesn't have oxygen bound to the iron, but it does have a water molecule, which shows up as a red sphere. (The file does not contain hydrogen atoms, so we see only the "O" of "H₂O"!)

The two pictures here were created with RASMOL. You can create similar pictures by accessing the PDB file 1mbn, and then clicking on "View Structure."