The structure of myoglobin, as determined by x-ray diffraction, exhibits all of the following EXCEPT which one?
A) The heme group is tucked into a pocket or cleft of the myoglobin molecule.
B) The myoglobin molecule has almost the same alpha helical content as the individual subunits of the hemoglobin molecule.
C) The myoglobin molecule has a very similar tertiary structure to the individual subunits of the hemoglobin molecule.
D) There is almost no water in the interior of the molecule.
E) The heme iron is linked to a tyrosine residue at its fifth coordination position.

Question

Quizplus · Accepted Answer

The heme iron in myoglobin is linked to a histidine residue, not a tyrosine residue, at its fifth coordination position. This histidine is often referred to as the proximal histidine.

The Structure of Myoglobin, as Determined by X-Ray Diffraction, Exhibits