Ronald L. Nagel, "Hemoglobin disorders: Molecular methods and protocols"

X-ray crystallography has played a key role in understanding the relationship between protein structure and physiological function. In particular, X-ray analysis of hemoglobin (Hb) crystals has been pivotal in the formulation of basic theories concerning the behavior of allosteric proteins. Methemoglobin (MetHb) from horse was the first three-dimensional (3D) structure of liganded Hb to be solved (1–4).