Hemoglobin and Binding Flashcards
How many alpha helices exist in myoglobin or a hemoglobin subunit?
8 (numbered A-H)
Where does the oxygen bind in hemoglobin?
In the heme group that resides between helices E and F.
What residue interacts to stabilize the iron bound in the heme group?
Histidine (proximal, F-helix)
What mutation causes sickle cell anemia?
Glu –> Val
Why hemoglobins coagulate in sickle cell patients?
Valine at position 6 of one of the subunits fits into a hydrophobic pocket on another protein causing it to stick. Coagulation is is worse in unoxygenated proteins
Membrane Anchors are often derivatives of…
Post translational modifications
Major contacts between the subunits of hemoglobin are located where?
a1b1, a2b2
Sliding contacts of hemoglobin are located where?
a1b2, a2b1
What are the sliding contacts?
19 amino acids that change significantly 6A during O2 binding
What happens on O2 binding?
15 degree rotation between the two alpha and beta dimers
