Structure of heamoglobin?
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Hemoglobin belongs to a clan of heme-proteins which contain a heme prosthetic group. The best known heme is Fe-protoporphyrin IX. Other members of the family include: b-type and c-type cytochromes, catalases and peroxidases. The function of Hb is to transport oxygen to cells, and it has to do so keeping the Fe++ in the reduced state.
Hemoglobin is a tetramer consisting of 2 pairs of one and the same dimers, alpha1beta1 and alpha2beta2 subunits. Each of the 4 chains contains one heme group, in which the Fe ion is coordinated to the 4 nitrogen of the tetrapyrrole ring and the nitrogen of His87 of helix F. The sixth coordination site is free for ligating oxygen
Tetrameric Hb occurs in two conformations: the oxygenated T-state and deoxygenated R-state. The individual chains inside each dimer are tightly packed together, but the two subunits are reversibly held together by a multitude of salt bridges and hydrogen bonds contained by the deoxy state.
"Hemoglobin (also spelled haemoglobin and abbreviated Hb or Hgb) is the iron-containing oxygen-transport metalloprotein in the red blood cells of vertebrates, and the tissues of some invertebrates"
"In most humans, the hemoglobin molecule is an assembly of four globular protein subunits. Each subunit is composed of a protein chain tightly associated near a non-protein heme group. Each protein chain arranges into a set of alpha-helix structural segments connected together in a globin fold arrangement, so call because this arrangement is the same folding motif used in other heme/globin proteins such as myoglobin. This folding pattern contains a pocket which strongly binds the heme group" Source(s): http://en.wikipedia.org/wiki/Hemoglobin#…