CHE 4341 Lecture Notes - Lecture 6: Torr, Coordinate Covalent Bond, Methemoglobin
Document Summary
Myoglobin (mb) in rbcs tetramer of 4 homologous mb like subunits in muscle monomer. 1st protein whose 3d structure was determined (x-ray. John kendrew used sperm whale mb (has lots of mb for o2 storage. Very similar 3d structure to a -subunit. Mb & each hb"s 4 subunits contains a heme prosthetic group (the non-aa portion of a protein that is ~ required for biological. His e7 (= distal his ) forces any ligand binding to fe(ii) to bind at a bent angle. The bent angle allows for o2 to bind fe(ii) on heme reversibly. Heme also held in place in hb & mb by hydrophobic interactions covalent bond to his f8 (=8th reside in f helix) Heme held in place to each hb subunit/mb by coordinate. Co (& other small molecule poisons like: cn-, n3-, no, h2s) Toxic bc they have a high affinity for fe(ii) in heme, especially when.
