Sperm Whale Myoglobin (oxygenated form)

The oxygenated form of sperm whale myoglobin (1a6m.pdb)

(Structure displays using JSmol and HTML5. If you don't see a structure try an alternate browser.)

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Make it easier to see the heme and the bound oxygen (in (magenta)
Proximal his (his covalently bound to the iron in heme) in spacefill.
Distal his (his near the bound oxygen) in spacefill.
Show only protein (not heme).
Myoglobin spacefilling(heme).
Hydrophilic AA in blue, hydrophobic in yellow; heme in green.
Cut halfway through myogolbin to see the interior (best in conjunction with the above command).
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Myoglobin includes a heme prosthetic group (a non-amino acid component of a functional protein). The heme is bound tightly in a hydrophobic pocket of the myoglobin. It is also bound by a covalent link between the "proximal histidene" (his93) of the protein. A second his (the "distal histidine" his64) is on the opposite side of the heme that restricts the space at the binding site, helping to decrease the affinity for CO relative to that of O2 (althought CO still binds much more tightly than does O2). As for all soluble globular proteins, hydrophilic amino acids are found mostly on the exterior, while the interior is largely hydrophilic.

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Copyright© Charles S. Gasser, 2010, 2013

Dept. of Molecular and Cellular Biology at the University of California, Davis.