CHE 4341 Lecture Notes - Lecture 7: Torr, Imidazole, Myoglobin
Document Summary
Perutz mechanism for hb"s positive o2 binding cooperativity: From study of x-ray crystal structures perutz proposed. Hb"s cooperatively from mechanical movement of protein scaffold. Mechanical communication: like a domino effect or rube goldberg. T-state is locked in tense conformation via h-bonds & ion pairs [these are not in r-state] Difficult for t-state to bind the 1st o2 bc his e7 & val e11block the 1st o2"s access to heme. 3 iron 0. 6 out of heme plane in t-state: fe2+ iron is 0. 6 out of heme plane when 1st o2 gets in & binds, it pulls fe2+ back into the heme plane. 4 his f8 is attached to the fe2+ is thus also pulled towards heme plane. 5 because his f8 is part of f helix, it pulls the f helix like a lever on a fulcrum. 6 when the f helix moves, to accommodate the spatial rearrangement caused by its movement, structure)
