Hemoglobin crystals

Much of this handbook is concerned with the how and why of crystallization and crystallizer design. This chapter will focus on the crystallization of one particular class of chemical compounds, namely the proteins. In the timeline of crystallization, protein crystallization is a newcomer. The first mention of protein crystal formation, roughly 150 years ago, involved crystallizing hemoglobin from the blood of various species (Lehman 1853 Reichert and Brown 1909 Debru 1983 McPherson 1991). This work was followed by the crystallization of a variety of proteins from plants to egg white (Sumner 1926). These early studies were pivotal in establishing that enzymes are proteins (Dounce and Allen 1988). The use of protein crystallization in purification and classification of biological chemicals resulted in the Nobel Prize for Chemistry being awarded to Sumner, Nothrop, and Stanley in 1946. 

Several pure hemoglobin solutions were later produced on a large scale for experimental use. A procedure was described for crystallization of hemoglobin and the product was evaluated in a series of animal trials (38—41). A 6 g/dL hemoglobin solution that had a P q of about 2.4—2.7 kPa (18—20... 

Application to biomolecules started as early as the mid-fifties with single-crystal EPR studies on hemoglobin (Bennett et al. 1955), but in hindsight it now appears that... 

Otto, B. R., Sijbrandi, R., Luirink, J., Oudega, B., Heddle, J. G., Mizutani, K., Park, S. Y., and Tame, J. R. (2005). Crystal structure of hemoglobin protease, a heme binding autotransporter protein from pathogenic Escherichia coli. f. Biol. Chem. 280, 17339-17345. 

Mehanna, A.S. Abraham, D.J. Comparison of crystal and solution hemoglobin binding of selected antigelling agents and allosteric modifiers. Biochemistry 1990, 29, 3944-3952. 

Saeo, M.K., Moure, C.M., Burnett, J.C., Joshi, G.S., and Abraham, D.J. High-resolution crystal structure of deoxy hemoglobin complexed with a potent allosteric effector. Protein Sci. 2001, 10, 951-957. 

In the crystalline state these two forms are not isomorphous, and adding substrate to ConA crystals causes them to shatter.48 (This is a common observation and occurs even in hemoglobin crystals.) The differences between the conformers in the ConA part of the complex are not fully known, but there is considerable rearrangement of the protein. The rates of the reaction are fast, and so in solution the protein must be able to fluctuate readily between its different forms. Comparison with lysozyme (earlier in this article) shows that when lysozyme binds its inhibitors, a conformational change does occur, but it is not so gross that in the solid state shattering of crystals occurs. 

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